Vigilohm IM400

DOCA0049EN-02 09/2015

Vigilohm IM400
Insulation Monitoring Device
User Manual
09/2015
DOCA0049EN-02

www.schneider-electric.com
 The information provided in this documentation contains general descriptions and/or technical character-
istics of the performance of the products contained herein. This documentation is not intended as a
substitute for and is not to be used for determining suitability or reliability of these products for specific user
applications. It is the duty of any such user or integrator to perform the appropriate and complete risk
analysis, evaluation and testing of the products with respect to the relevant specific application or use
thereof. Neither Schneider Electric nor any of its affiliates or subsidiaries shall be responsible or liable for
misuse of the information contained herein. If you have any suggestions for improvements or amendments
or have found errors in this publication, please notify us.
No part of this document may be reproduced in any form or by any means, electronic or mechanical,
including photocopying, without express written permission of Schneider Electric.
All pertinent state, regional, and local safety regulations must be observed when installing and using this
product. For reasons of safety and to help ensure compliance with documented system data, only the
manufacturer should perform repairs to components.
When devices are used for applications with technical safety requirements, the relevant instructions must
be followed.
Failure to use Schneider Electric software or approved software with our hardware products may result in
injury, harm, or improper operating results.
Failure to observe this information can result in injury or equipment damage.
© 2015 Schneider Electric. All rights reserved.

2 DOCA0049EN-02 09/2015
 Table of Contents

Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
About the Book. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 1 Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Physical Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Chapter 2 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Safety Measures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Flush Mounting and Dismantling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Mounting on and Dismantling from a Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Typical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Chapter 3 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
R and C Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Configuration and Accuracy Zones by Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Monitoring the System Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Operation on Systems with a Voltage Greater Than 480 Vac/dc . . . . . . . . . . . . . . . . . . . . . 46
Insulation Fault Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Injection Inhibition Input and Exclusion Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Self-Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Chapter 4 Human Machine Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Vigilohm IM400 Menu Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Navigating the Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Status Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Special Status Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Modifying Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Insulation Fault Log . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Trend Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Chapter 5 Communication via Modbus RS-485 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Configuring RS-485 Communication Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Table of Modbus Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Modbus Registers Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Chapter 6 Maintenance and Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Maintenance and Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Chapter 7 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Glossary ...................................................... 85

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 Safety Information

Important Information

NOTICE
Read these instructions carefully, and look at the equipment to become familiar with the device before
trying to install, operate, service, or maintain it. The following special messages may appear throughout
this documentation or on the equipment to warn of potential hazards or to call attention to information that
clarifies or simplifies a procedure.

PLEASE NOTE
Electrical equipment should be installed, operated, serviced, and maintained only by qualified personnel.
No responsibility is assumed by Schneider Electric for any consequences arising out of the use of this
material.
A qualified person is one who has skills and knowledge related to the construction and operation of
electrical equipment and its installation, and has received safety training to recognize and avoid the
hazards involved.

DOCA0049EN-02 09/2015 5
FCC Notice
This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant
to part 15 of the FCC Rules. These limits are designated to provide reasonable protection against harmful
interference when the equipment is operated in a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio communications. Operation of this equipment
in a residential area is likely to cause harmful interference in which case the user will be required to correct
the interference at his own expense.

6 DOCA0049EN-02 09/2015
 About the Book

At a Glance

Document Scope
This manual is intended for use by designers, panel builders, installers, system integrators, and
maintenance technicians who use ungrounded power systems (IT) with insulation monitoring devices
(IMDs).

Validity Note
The Vigilohm IM400 is used to monitor lines to earth insulation of ungrounded power systems. This
includes industrial and marine electrical systems, infrastructures, and power generation systems such as
photovoltaic and wind turbines. Thanks to the adaptive multi-frequency injection signal, the Vigilohm IM400
is suitable for power and control circuits that contain switching power electronics (speed drives, motor
starters, inverters, thyristors) and DC components. The Vigilohm IM400 allows automatic and manual fault
location.

Related Documents

Title of Documentation Reference Number

Instruction Sheet: Vigilohm IM400 Insulation Monitoring Device S1B9007601
Vigilohm Catalog PLSED310020EN
PLSED310020FR
The IT earthing system: a solution to improve industrial electrical PLSED110006EN
network availability - Application guide
Système de liaison à la terre IT - Une solution pour améliorer la PLSED110006FR
disponibilité des réseaux électriques dans l’industrie - Guide
d’application
System earthings in LV Cahier technique n° 172
Les schémas des liaisons à la terre en BT (régimes du neutre)
The IT system earthing (unearthed neutral) in LV Cahier technique n° 178
Le schéma IT (à neutre isolé) des liaisons à la terre en BT

You can download these technical publications and other technical information from our website at
http://download.schneider-electric.com

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 Vigilohm IM400
Vigilohm IM400 - Presentation
DOCA0049EN-02 09/2015

Chapter 1
Presentation

Presentation

What Is in This Chapter?

This chapter contains the following topics:
Topic Page
Presentation 10
Physical Description 12
Accessories 13

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Vigilohm IM400 - Presentation

Presentation

Using Ungrounded IT System to Improve Power Availability and Reduce Risk of Fire
Continuity of service is an essential operational requirement for power systems, as it helps protecting
people and property. The use of ungrounded IT power system is mandatory when power interruption would
lead to a hazard for people and equipment. It is the case of medical operating theaters and marine
applications.
Ungrounded IT system is recommended when unavailability of power would result in losing production, or
occur significant downtime costs. When the first insulation fault current can lead to a risk of fire or
explosion, it is recommended to limit the first fault current by using ungrounded systems. It is the case in
environments such as oil and gas, chemical, or photovoltaic. The IT grounding system is chosen in certain
cases because it can help facilitating preventive and corrective maintenance operations.
The ungrounded IT system helps making continuity of service. Even after a first insulation fault has
occurred, the installation can continue to function without presenting any danger to people or equipment.
However, the faulty circuit must be detected and repaired before a second insulation fault occurs. The fact
that the IT system can tolerate a first insulation fault means that maintenance operations can be improved,
planned, and carried out in good conditions.

Monitor Insulation Resistance (R)

Standards IEC 60364 and IEC 61557-8 state that IT systems must be either ungrounded or grounded
using a sufficiently high value impedance (resistance or inductance).
In the event of a first insulation fault, the ground fault current is low and interrupting the faulty circuit is
unnecessary. However, given the fact that a second insulation fault could potentially cause the circuit
breaker to trip, an insulation monitoring device must be installed to indicate a first insulation fault. This
device must trig an audible or a visual signal.
By constantly monitoring the insulation resistance, you can track the system insulation quality, which is an
insight for preventive maintenance.

Monitor the Leakage Rate (C)

According to standard IEC 60364-4-41, the following conditions must apply to provide protection against
indirect contact in AC power systems:

RA × Id ≤ 50 V
Where:
 RA is the resistance value of the grounding connection of the equipment exposed-conductive-parts.
 Id is the ground fault current, in A.
 50 V is the maximal acceptable voltage for indirect contacts.

In ungrounded, 3-phase, AC power systems, fault current Id is .

Where:
 is the earth leakage capacitance of the power system.
 is the frequency of the power system.
 is the phase to neutral voltage.
Therefore the following condition must apply to provide protection against indirect contacts:
.
Thus it is necessary to monitor the earth leakage capacitance C and to have a low-resistance value of
grounding connections.
For more information, see Cahier technique n°178.

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 Vigilohm IM400 - Presentation

Functions of Vigilohm IM400 Insulation Monitoring Device

Vigilohm IM400 is a digital insulation monitoring device (IMD) for low-voltage IT power systems with
ungrounded neutral. Vigilohm IM400 can be used to monitor the insulation of a system and to signal
insulation faults.
Vigilohm IM400 applies several patented combinations of a low-frequency AC voltage between the system
and ground to provide accurate insulation monitoring in complex applications. The insulation is then
assessed based on the current value returned. This method is used for all types of systems: AC, DC,
mixed, with rectifiers, with variable speed drives, with inverters, and so on.
Vigilohm IM400 offers the following functions:
 Insulation resistance display (R)
 Detection of insulation faults in accordance with a configurable threshold
 Display of earth leakage capacitance (C) and associated impedance (Zc)
 Communication via the Modbus RS-485 protocol
 Injection inhibition via logic input
 Insulation fault log
 Trending of the insulation resistance (R) from last hour to last year
 Quick setup of the monitoring parameters according to the applications
 Compatibility with voltage adaptors (Umax = 1,700 Vac Ph-Ph or Umax = 1,200 Vdc)

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Physical Description

Physical Description

A Display
B Contextual menu buttons
C MENU button
D Red indicator light for Vigilohm IM400 product status
E Yellow indicator light for Modbus communication indication
F Green indicator light for correct insulation indication
G White indicator light for preventive insulation alarm
H Yellow indicator light for insulation alarm
I ESC button for returning to previous menu or canceling a parameter entry
J Vigilohm product catalog number
K Vigilohm serial number
L Auxiliary power supply terminal block
M Injection terminal block
N Insulation alarm relay terminal block
O Preventive insulation alarm relay terminal block
P Modbus RS-485 terminal block
Q Injection inhibition input terminal block

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Accessories

Presentation
The following accessories are required depending on the type of installation on which Vigilohm IM400 is
installed:
 A Cardew C surge limiter
 A ZX impedance
 A voltage adaptor

Below is a list of accessories for the Vigilohm devices:

Accessory Catalog number

250 V Cardew C surge limiter 50170
440 V Cardew C surge limiter 50171

660 V Cardew C surge limiter (1) 50172

1,000 V Cardew C surge limiter(1) 50183

Cardew C base(2) 50169

ZX impedance 50159

IM400-1700 voltage adaptor (3)  IMD-IM400-1700

 IMD-IM400-1700C

PHT1000 voltage adaptor(4) 50248

(1) Compatible with the Vigilohm IM400 when used with voltage adaptor IM400-1700 or PHT1000.
(2) Compatible with all Cardew C catalog numbers.
(3) For power systems with Umax > 480 Vac Ph-Neutral, or Umax > 830 Vac Ph-Ph, or Umax > 480 Vdc without
insulation fault locator.
(4) For power systems with Umax > 480 Vac Ph-Neutral, or Umax > 830 Vac Ph-Ph, or Umax > 480 Vdc with
insulation fault locator.

NOTE: For information regarding automatic and mobile insulation fault locating accessories, refer to the
relevant section (see page 47).

Cardew C Surge Limiter

Function The Cardew C is used if the insulation monitoring device is connected to the secondary of an MV/LV
transformer (according to the rules and conventions that apply in the various countries).
It helps protecting the low-voltage (LV) installation against overvoltage hazards.
It is connected to the transformer secondary.
The Cardew C can be used on the following systems:
 U < 1000 Vac
 U < 300 Vdc

Selection Un: Nominal Phase-to-Phase Voltage of AC Ui: Arcing Voltage Type of Cardew C
table System
Accessible neutral Not accessible neutral
U ≤ 380 V U ≤ 220 V 400 V < Ui ≤ 750 V 250 V
380 V < U ≤ 660 V 220 V < U ≤ 380 V 700 V < Ui ≤ 1,100 V 440 V
660 V < U ≤ 1,000 V 380 V < U ≤ 660 V 1,100 V < Ui ≤ 1,600 V 660 V
1,000 V < U ≤ 1,560 V 660 V < U ≤ 1,000 V 1,600 V < Ui ≤ 2,400 V 1,000 V
Dimensions

Mounting  Cardew C mounted directly on busbars

 Mounting with plate-mounted base

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Vigilohm IM400 - Presentation

Connection

ZX Impedance

Function The ZX impedance creates an installation with an impedance grounded neutral system (1500 Ω at
50 Hz).
The ZX remains connected during insulation fault locating at 2.5 Hz:
 1,500 Ω at 50 Hz
 1 M Ω at 2.5 Hz

The ZX impedance must be used on systems with U ≤ 500 Vac.

Dimensions

Mounting On mounting plate

Connection

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Voltage Adaptors
The optional voltage adaptors are:
 IM400-1700
 PHT1000

Function The IM400-1700 and PHT1000 voltage adaptors can be used to connect a Vigilohm IM400 to voltage
systems higher than 480 Vac L-L. The wire connecting IM400-1700 to Vigilohm IM400 must have the
same voltage rating than the monitored network.
The compatibility of voltage adaptors with insulation fault location is as follows:
 The IM400-1700 voltage adaptor is not compatible with insulation fault location.
 The PHT1000 voltage adaptor is compatible with insulation fault location.

Dimensions IM400-1700 PHT1000

Mounting On DIN rail On mounting plate

Connection Monitored network Monitored network

(1) Voltage adaptor connected to a phase

(2) Voltage adaptor connected to neutral

S3 Subassembly (Retrofit)
Insulation alarm thresholds of the Vigilohm IM400 must be set higher than 2 kΩ to take into account internal
impedance of the no longer commercialized S3 subassembly.

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Vigilohm IM400 - Presentation

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 Vigilohm IM400
Vigilohm IM400 - Installation
DOCA0049EN-02 09/2015

Chapter 2
Installation

Installation

What Is in This Chapter?

This chapter contains the following topics:
Topic Page
Safety Measures 18
Dimensions 20
Flush Mounting and Dismantling 21
Mounting on and Dismantling from a Grid 24
Connection 25
Typical Applications 26

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Vigilohm IM400 - Installation

Safety Measures

Specific Hazard Associated with Insulation Monitoring Devices (IMDs)

In the case of almost all electric and electronic devices, the device power supply is the root cause of
electrical hazards. The hazard can be mostly reduced by disconnecting the power supply.
This is not the case with insulation monitoring devices, which are connected to the system via the injection
wire.
So this connection must be broken before carrying out any kind of work on the product.

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
 Before carrying out work of any kind, disconnect the Vigilohm IM400 from the monitored system by
disconnecting wiring terminals 1, 2, and 3 of injection terminal block. Disconnect all the power supplies
running to the Vigilohm and the equipment on which it is installed.
 Always use a correctly calibrated voltage tester to check that the injection wire and power supply have
been properly disconnected.
Failure to follow these instructions will result in death or serious injury.

Specific Hazard Associated with IM400-1700 Voltage Adaptor

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
Connect the ground wiring terminal (4) on the IM400-1700 voltage adaptor to a protective earth ground
(PE) conductor.
Failure to follow these instructions will result in death or serious injury.

Other Safety Measures

Carefully read through the safety measures described below. You are always required to implement them
fully before attempting to install, repair, or service electrical equipment.

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
 Wear suitable personal protective equipment and follow the currently applicable electrical safety
instructions.
 This equipment may only be installed by qualified electricians who have read all the relevant
information.
 NEVER work alone.
 Before performing visual inspections, tests, or maintenance on this equipment, disconnect all sources
of electric power. Assume that all circuits are live until they have been completely de-energized,
tested, and tagged. Pay particular attention to the design of the power system. Consider all power
supply sources, particularly the potential for backfeed.
 Before closing protective covers and doors, carefully inspect the work area to ensure that no tools or
objects have been left inside the equipment.
 Take care when removing or replacing panels. Take special care to ensure that they do not come into
contact with live busbars. To minimize the risk of injuries, do not tamper with the panels.
 The successful operation of this equipment depends upon proper handling, installation, and operation.
Failure to follow basic installation procedures can lead to personal injury as well as damage to
electrical equipment or other property.
 NEVER shunt an external fuse/circuit breaker.
 The Vigilohm must be installed in a suitable electrical cabinet.
Failure to follow these instructions will result in death or serious injury.

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A dielectric test (Hi-Pot) or a Megger test on a device installed in the power system monitored by the
Vigilohm IM400 can damage the Vigilohm IM400.

NOTICE
HAZARD OF PRODUCT DAMAGE
Before performing a dielectric test (Hi-Pot) or a Megger test, disconnect the Vigilohm input and output
wires.
Failure to follow these instructions can result in equipment damage.

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Vigilohm IM400 - Installation

Dimensions

Vigilohm IM400 Dimensions

CAUTION
CUTTING HAZARD
Trim the edges of the cut-out plates to remove any jagged edges.
Failure to follow these instructions can result in injury or equipment damage.

Constraints for Flush Mounting

Observe the correct distances between devices.

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 Vigilohm IM400 - Installation

Flush Mounting and Dismantling

Presentation
Vigilohm IM400 can be attached to any flat, rigid vertical support using the spring clips supplied. The device
must not be tilted following installation.
To free up useful space for control gear, you can attach the Vigilohm to the front panel of the floor-standing
or wall-mounted enclosure.
For USA and Canada, Vigilohm IM400 mounting is to be open type only.

Installing
Before attaching the Vigilohm, check the following:
 The mounting plate must have a thickness of between 0.8 mm (0.03 in) and 3.2 mm (0.12 in).
 A rectangle measuring 148 x 112 mm (5.83 x 4.41 in) must be cut out from the plate so the device can
be installed.
 No terminal blocks are connected to the unit.

To install the Vigilohm, proceed as follows:

Step Action
1 Insert the Vigilohm in the cut-out in the mounting plate by tilting the device forward slightly.

2 Depending on the thickness of the mounting plate, clip the spring clips into the mounting slots on the
device as described below. First, clip the spring clip at the top.
If the mounting plate thickness (X) is: The mounting slot to be used is:
0.8 mm ≤ X ≤ 2 mm
(0.03 in ≤ X ≤ 0.08 in)

If the mounting plate thickness (X) is: The mounting slot to be used is:
2 mm < X ≤ 3.2 mm
(0.08 in ≤ X ≤ 0.12 in)

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Vigilohm IM400 - Installation

Step Action
3 Clip the 2 spring clips on the device sides then the 2 spring clips at the device bottom.

4 Wire up and insert the terminal blocks as shown in the relevant wiring diagram (see page 25).

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Removing
To remove the Vigilohm from a mounting plate, proceed as follows:

Step Action
1 Disconnect the terminal blocks from the Vigilohm.
2 Deal with each of the spring clips as follows: insert the blade of a screwdriver between the spring clip
and the device. Then use the screwdriver as a lever to release the spring clip.
Start releasing the spring clips at the top and bottom of the device.

3 Release the 2 spring clips at the device sides.

4 Remove the Vigilohm from the plate.

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Vigilohm IM400 - Installation

Mounting on and Dismantling from a Grid

Presentation
To install the Vigilohm on a grid using fixing brackets (reference 01199 Prisma catalog) or equivalent. The
device must not be tilted following installation.
When mounting the device or dismantling it using clamps, you can keep the terminal blocks connected and
wired up, or you can remove them and keep them to hand.
For USA and Canada, Vigilohm IM400 mounting is to be open type only.

Mounting
To install the Vigilohm on a grid using fixing brackets, proceed as follows:

Step Action
1 Position the fixing brackets on the Vigilohm and tighten the screws and washers as described below
(tightening torque: 1.2 N.m (8.85 lb-in.).

2 Attach the assembly to the grid using clamps.

Removing
To remove the Vigilohm from a grid, unscrew the clamps from the grid to release the device.

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 Vigilohm IM400 - Installation

Connection

Connection Diagram
The diagram below illustrates how to connect the Vigilohm to a single-phase or three-phase 3- or 4-wire
power system, or a DC power system.

The relay operating mode (failsafe or standard) is controlled via the HMI of the Vigilohm device or with
Modbus communication.
NOTE: Circuit breakers (reference MGN61334 or equivalent) can be used to replace listed fuses.

Connection Characteristics
All the Vigilohm IM400 wiring terminals have identical wiring capabilities.
The table shows the characteristics of the cables that can be used to connect the wiring terminals:

Stripped Length Cross-Section Area Tightening Torque Type of Screwdriver

7 mm (0.27 in) 0.2...2.5 mm² (AWG 0.8 N•m (7 lb-in) Flat, ≤ 3 mm (≤ 0.10 in)
24...14)

Cross-section area and voltage rating of wires must be suitable to the load current and to the voltage to
which it is connected. The following characteristics need to be considered:
 Auxiliary power supply consumption: 25 VA / 10 Ω
 Current flowing to the monitoring network wiring terminal: less than 20 mA
 Current flowing to the injection inhibition wiring terminal: 5 mA
 Current flowing to the insulation alarm and to the preventive insulation alarm wiring terminals depends
on the power rating of the insulation alarm indicator.

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Vigilohm IM400 - Installation

Typical Applications

Presentation
The following section presents five insulation monitoring applications for an IT power system:
 One application with a standalone Vigilohm IM400
 One application with Vigilohm IM400 where the insulation alarm and preventive insulation alarm outputs
are sent to a supervisor
 One application with Vigilohm IM400 where the insulation alarm and preventive insulation alarm outputs
are sent to a supervisor, and locating the insulation fault is done using an XD301 or XD312 automatic
fault locator and an XRM mobile fault locator
 One application with a Vigilohm IM400 connected to a communication network
 One application with a Vigilohm IM400 connected to a communication network, and locating the
insulation fault is done using an XD308C insulation fault locator

Monitoring the Insulation of an IT Power System with a Standalone Vigilohm IM400

An IT power system is a system involving the use of a transformer whose neutral is not grounded.
The insulation is monitored by one Vigilohm IM400 with the following characteristics:
 IM400 is powered by the system that it monitors.
 IM400 is connected to neutral (or to one phase) and ground.
 The insulation fault threshold level is the only IM400 setting to be set up. The preventive insulation alarm
can be set up.
 Vigilohm IM400 has a single relay output to control a light or a buzzer.

Monitoring the Insulation of an IT Power System with a Vigilohm IM400 Where the Insulation Alarm Is Sent to a
Supervisor
The insulation is monitored by a Vigilohm IM400 whose insulation alarm and preventive insulation alarm
outputs are connected to an available input on a networked device (a PLC, for example). This device is
itself connected to a supervisor via a communication network.
As far as this architecture is concerned, the restriction is that only the insulation fault and preventive
insulation alarm information is available at supervisor level.

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Monitoring the Insulation of an IT Power System with a Vigilohm IM400 and Insulation Fault Location Where the
Insulation Alarm Is Sent to a Supervisor
The insulation is monitored by a Vigilohm IM400 whose insulation alarm and preventive insulation alarm
outputs are connected to an available input on a networked device (a PLC, for example). This device is
itself connected to a supervisor via a communication network.
Locating the insulation fault is done using XD301 or XD312 devices. The XD301 or XD312 output relay is
connected to an available input on a networked device.
The XRM mobile insulation fault locator is used to locate accurately the area where the insulation fault is.
As far as this architecture is concerned, the restriction is that only the insulation fault information and group
of faulty feeder are available at supervisor level.

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Vigilohm IM400 - Installation

Monitoring the Insulation of an IT Power System with a Vigilohm IM400 Connected to a Communication Network
When the Vigilohm IM400 insulation monitoring device is linked to the supervisor via a Modbus connection,
the following actions are supported:
 Display:
 Product status
 Status of the insulation alarm (active, not active, acknowledged) and status of the preventive
insulation alarm
 Details of the last 30 time-tagged events
 Values for R and C to create tables or curves for monitoring these values over variable periods

 Configuring the product remotely: all the settings can be accessed remotely, except for the Modbus
parameters (Address, Auto Config, Baudrate, and Parity).

The Ethernet gateway can be an EGX series or Com'X series, for example.

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Monitoring the Insulation of an IT Power System with a Vigilohm IM400 Connected to a Communication Network and
Insulation Fault Location
When the Vigilohm IM400 insulation monitoring device is linked to the supervisor via a Modbus connection,
the following actions are supported:
 Display:
 Product status
 Status of the insulation alarm (active, not active, acknowledged) and status of the preventive
insulation alarm
 Details of the last 30 time-tagged events
 Values for R and C to create tables or curves for monitoring these values over variable periods

 Configuring the product remotely: all the settings can be accessed remotely, except for the Modbus
parameters.
Using the XD308C insulation fault location device in addition with the XLI300 communication interface
allows also the supervisor to monitor remotely all the feeders and so to report precisely any insulation fault
location.
The XRM mobile insulation fault locator is used to locate accurately the area where the insulation fault is.

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Vigilohm IM400 - Installation

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 Vigilohm IM400
Vigilohm IM400 - Functions
DOCA0049EN-02 09/2015

Chapter 3
Functions

Functions

What Is in This Chapter?

This chapter contains the following topics:
Topic Page
R and C Measurement 32
Configuration and Accuracy Zones by Application 33
Monitoring the System Insulation 36
Operation on Systems with a Voltage Greater Than 480 Vac/dc 46
Insulation Fault Location 47
Injection Inhibition Input and Exclusion Management 48
Self-Test 53

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R and C Measurement

Insulation Measurements
Vigilohm IM400 is designed:
 To monitor the IT power system insulation,
 To measure:
 The insulation resistance R (Ω) continuously,

 C, which is the leakage capacitance of the distribution system to ground (µF),

 To calculate the impedance Zc (kΩ) associated with C.

Effect of Leakage Capacitance on the Measurement Accuracy of R

The leakage capacitance (C) creates a leakage path for the measurement signal and reduces the level of
the useful signal that flows through the insulation resistance (R).
The Vigilohm IM400 injects a signal with low frequencies and includes high-performance integration
algorithms. It makes it compatible with large power systems that have a high value of leakage capacitance.
For other IMDs using switching mode measurement signals, the leakage capacitance (C) has an impact
on the measurement accuracy of the insulation resistance (R).
The Vigilohm IM400 correctly operates in power systems with leakage capacitance up to 500 µF and
photovoltaic systems with leakage capacitance up to 2,000 µF.

Effect of Frequency Disturbances on the Measurement Accuracy of R

Switching mode power electronic devices apply residual voltages between the power system and ground.
These voltages may interfere with IMDs measurements.
The Vigilohm IM400 injects an adaptive multi-frequency measurement signal that makes it operate out of
the disturbance range. This measurement signal is combined with efficient integration algorithms to allow
accurate measurements regardless of the frequency disturbances.

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Configuration and Accuracy Zones by Application

Configuration by Application
Vigilohm IM400 is designed and tested to be compliant with different applications:
 Power circuits: industrial or marine applications that contain power loads and power electronics such as
speed drives, inverters, or rectifiers.
 Control circuits: auxiliary control circuits used to drive power systems. These circuits contain sensitive
loads such as PLCs, IOs, or sensors.
 Photovoltaic systems: large photovoltaic power generation systems. This application is characterized
by high DC rated voltage (1,000 V) and high system leakage capacitance (up to 2,000 µF).

Applications
To optimize the measurement performances of Vigilohm IM400 according to the application, set the
application parameter by selecting Menu → Settings → Network → App..
Set the App. parameter value depending on the type of application on which Vigilohm IM400 is installed:

Parameter value Application

Power C. (factory setting) Power circuits
Control C. Control circuits
Photovolt Photovoltaic

The measurement parameters accessible in the Network menu are automatically preset depending on the
application:
 Filtering
 Fault Locating
 V. Adaptor
 Frequency
 Injection

There is no need to configure these parameters in typical conditions.

The table shows the preset values of the measurement parameters according to the application parameter:

Preset values Application parameters

Power C. Control C. Photovolt
Filtering Medium Medium Medium
Fault Locating ON ON OFF
V. Adaptor None None HV1700
Frequency 50 Hz DC DC
Injection Std Min Max

Filtering (Measurement Quality)

The filtering parameter is to be set depending on the installation type. This parameter is used to smooth
out values of insulation measures that always depend on equipment operating on the system. Criteria are:
 Number of loads
 Type of loads
 Size of the system (effects C)
 Load switching

The Vigilohm IM400 is designed to provide accurate insulation resistance and capacitance measurement
on highly disturbed systems with power electronic devices. A filtering function is embedded to improve the
measurement stability to avoid display fluctuation, undesired transient insulation, and preventive insulation
alarm. The response time associated with this filtering function does not affect the IT power system.

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Three settings are available for the Filtering parameter.

Parameter value Example of use Measurement Response time required to

refresh time detect an insulation fault
(for C = 1 µF)
Short Recommended in maintenance mode. 0.8 s (not 1 s (not available in
Diagnose fast variation of the insulation available in photovoltaic application)
resistance and leakage capacitance. photovoltaic
Mostly used in the following cases: application)
 Detecting short time transient insulation
faults.
 When manually locating insulation
faults by opening circuit breakers.
Medium Recommended in operation mode. 8s 40 s
Dedicated to monitor insulation of typical
installations.
Long Recommended in operation mode. 80 s 400 s
Dedicated to monitor insulation of highly
disturbed installations and/or installations
with high leakage capacitance.

Locating Insulation Faults

The Vigilohm IM400 can be used with XD301, XD312, or XD308C automatic insulation fault locator or XRM
mobile insulation fault locators to detect where the insulation fault is located. Activate or deactivate this
feature through Fault Locating parameter.
Two settings are available for the Fault Locating parameter.

Parameter value Description

OFF The Vigilohm IM400 does not inject a fault locating current.
ON The Vigilohm IM400 injects a fault locating current compatible with XD301, XD312, XD308C,
and XRM devices. Insulation fault location is not compatible with HV1700 voltage adaptor.

Voltage Adaptors
The Vigilohm IM400 can be used with IM400-1700 and PHT1000 voltage adaptors to monitor power
systems with a rated voltage higher than 480 Vac L-L.
IM400-1700 voltage adaptor can also be used in power systems below 480 Vac/dc to increase the internal
impedance of the Vigilohm IM400.
Three settings are available for the V. Adaptor parameter.

Parameter value Description

None Vigilohm IM400 is directly connected to the monitored power system. The power system should
have a rated voltage lower or equal to 480 Vac/dc.
HV1700 Vigilohm IM400 uses IM400-1700 voltage adaptor to connect to the monitored network
(see page 15).
Locating an insulation fault cannot be done using Vigilohm IM400 with IM400-1700.
HV1700 cannot be set up when the parameter Fault Locating is set to ON.
PHT1000 Vigilohm IM400 uses PHT1000 voltage adaptor to connect to the monitored network
(see page 15).
Locating an insulation fault can be done using Vigilohm IM400 with PHT1000.

System Frequency
This is the rated frequency of the monitored power system.
Four settings are available for the Frequency parameter:
 DC
 50 Hz
 60 Hz
 400 Hz

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Injection
This is the level of measurement voltage and measurement current that are injected between the
monitored power system and ground.
Four settings are available for the Injection parameter.

Parameter value Example of use Measurement voltage Measurement current

value value
Min Sensitive control circuits < 15 Vpeak < 375 µApeak
Low Not sensitive control circuits or < 33 Vpeak < 825 µApeak
power circuits with low values of
leakage capacitance
Std Power circuit applications with high < 120 Vpeak < 3 mApeak
values of leakage capacitance
Max (setting Photovoltaic application < 120 Vpeak < 300 µApeak
applicable only for
Vigilohm IM400 used
with IM400-1700)

Impedant IT Networks (HRG)

The Vigilohm IM400 can be used to monitor power systems with a grounding resistance inserted between
the neutral and the earth.
If the value of this neutral grounding resistance is entered through the HRG (High-Resistance Grounding)
parameter, the Vigilohm IM400 compensates the measured insulation resistance. It does it with the value
of the neutral grounding resistance, offsetting it to report the actual insulation resistance. In this case, the
actual insulation resistance (offset of the neutral grounding resistance) is used against the insulation alarm
threshold and the preventive insulation alarm threshold to trigger the insulation and preventive insulation
alarm relays.
HRG compensation is applicable only if the neutral is connected to ground through a resistance. HRG is
not compatible with RLC (non-linear) grounding circuits.
Two settings are available for the HRG parameter.

Parameter value Description

OFF The Vigilohm IM400 does not compensate the reported insulation resistance with the value of
the neutral grounding resistance.
0.1...500 kΩ The Vigilohm IM400 compensates the measured insulation resistance with the value of the
neutral grounding resistance.

Accuracy by Application
The accuracy zones of typical performance for Vigilohm IM400 depend on the application.
Example: For photovoltaic systems, the insulation resistance is:
 ±1 kΩ from 0 to 7 kΩ
 ±15% from 7 to 50 kΩ with leakage capacitance C = 50 µF
 ±15% from 7 to 10 kΩ with leakage capacitance C = 500 µF

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Vigilohm IM400 - Functions

Monitoring the System Insulation

Functional Description
The Vigilohm monitors the IT system insulation resistance (kΩ) in accordance with the following timing
diagram:

An insulation decrease is detected on the system. The insulation resistance drops below the
preventive insulation alarm threshold. The preventive insulation alarm relay switches and the preventive
insulation alarm indicator light lights up.
An insulation fault is detected on the system.
Once T (insulation alarm delay) has elapsed, Vigilohm IM400 switches to the insulation alarm state.
The insulation alarm relay switches and the insulation alarm indicator light lights up.
Press the button to acknowledge the insulation alarm.
Both the insulation alarm relay and the preventive insulation alarm relay toggle back to their initial state.
Depending on the setup of the I/Os, the preventive insulation alarm relay and the insulation alarm relay
may or may not toggle back to their initial states. The timing diagram above represents the case when
the I/Os are set up to acknowledge the relays (see page 42).
The insulation fault has been corrected or disappeared. Vigilohm IM400 reverts to normal status.
When the Vigilohm in the insulation alarm state is not acknowledged by the user, and the insulation rises
again above the insulation alarm threshold, then the insulation fault is recorded as transient.

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 Vigilohm IM400 - Functions

Status Information
The display and the five indicator lights on Vigilohm IM400 indicate the current status of the product.

Indicator lights Description

Product Modbus Insulation Preventive Insulation
status communication status insulation alarm
status alarm
Vigilohm IM400 de-energized.
OFF OFF OFF OFF OFF
– Vigilohm IM400 energized.
OFF ON OFF OFF No insulation fault detected.
– Vigilohm IM400 energized.
OFF OFF ON OFF Preventive insulation alarm detected.
– Vigilohm IM400 energized.
OFF OFF OFF ON Insulation fault detected.
– Vigilohm IM400 energized.
OFF ON OFF No insulation fault detected but transient insulation fault
Flashing has been detected.
– Vigilohm IM400 energized.
OFF OFF ON Preventive insulation alarm detected. Transient
Flashing insulation fault has been detected.
– Vigilohm IM400 energized.
OFF Flashing OFF OFF Injection de-activated by using injection inhibition input.
– – – Vigilohm IM400 energized.
OFF Flashing Modbus communication active.
Vigilohm IM400 energized but inoperative.
ON OFF OFF OFF OFF The IM400 product and its installation should be checked
by a maintenance operator.

Insulation Alarm and Preventive Insulation Alarm Thresholds

Two methods are available for changing the Vigilohm IM400 insulation alarm and preventive insulation
alarm thresholds:
 Manually set the corresponding parameter by selecting Menu → Settings → Ins. Alarm, or
 Use Modbus communication (see page 70).

The available settings for the insulation alarm and preventive insulation alarm thresholds are as follows:

Threshold Setting range Factory value

Insulation alarm 0.04...500 kΩ 1 kΩ
Preventive insulation alarm  1 kΩ...1 MΩ OFF
 OFF

Insulation alarm and preventive insulation alarm thresholds are saved in an internal non-volatile memory.
They remain unchanged after a power cut.
The preventive insulation alarm threshold must always be set higher than the insulation alarm threshold.
An insulation alarm is cleared when the insulation level reaches 20% above the threshold.

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Vigilohm IM400 - Functions

Hysteresis on Alarm and Preventive Insulation Alarm Thresholds

When the measured insulation value is close to the setup threshold, fluctuations of measures can trigger
erroneous preventive insulation alarms because the measure fluctuates around the threshold.
To limit the instability, a hysteresis principle is applied:
 When the measured insulation value decreases and drops below the setup threshold, the insulation
alarm or preventive insulation alarm is triggered or the countdown begins if an insulation alarm delay
has been set-up.
 When the measured insulation value increases and reaches a value above 1.2 time the threshold of the
setting (that is, setup threshold value +20%), the alarm or the preventive insulation alarm is deactivated.
The following diagrams show the behaviors:
 Insulation monitoring device without hysteresis:

 Vigilohm with 20% hysteresis:

Insulation Alarm and Preventive Insulation Alarm Time Delays

Insulation alarm and preventive insulation alarm delays are time filters. They are used to filter transient
insulation faults. The Vigilohm IM400 does not report insulation faults that do not remain for a duration
longer than the delays set up.
To access the time delay parameter, select Menu → Settings → Ins. Alarm.

Setting Setting range Factory value

Ins. Al. Delay (insulation alarm time delay) 0 s...120 minutes 0s
Prev. Al. Del. (preventive insulation alarm time delay) 0 s...120 minutes 0s

NOTE: The preventive insulation alarm time delay setup is not displayed when the preventive insulation
alarm threshold value is set to OFF.

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 Vigilohm IM400 - Functions

Detecting Disconnection of Injection Wiring Terminal

This function is based on the detection of a high insulation resistance in the system, and allows the
following disconnections to be detected:
 Injection wire.
 Ground wire.
 Between Vigilohm IM400 and IM400-1700 voltage adaptor.
 Between Vigilohm IM400 and PHT1000 voltage adaptor.

To access the parameter, select Menu → Settings → Ins. Alarm.

Setting Setting range Factory value

Disconnect. Inj. (disconnected injection) ON / OFF OFF

On small networks without loads and IT transformer, where the insulation level is high, or during
commissioning without loads and without IT transformer, it is recommended to set the parameter to OFF.
Detection of disconnection between Vigilohm IM400 and IM400-1700 or PHT1000 voltage adaptors is
always active and does not depend on the value of the Disconnect. Inj. parameter.
If the injection disconnects, Vigilohm IM400 triggers a product status alarm, described in Disconnected
Injection Detection (see page 61). The product status LED becomes red.

Insulation Alarm Relay

Depending on the status of the insulation, the insulation alarm relay is activated or deactivated according
to the mode selected:
 Failsafe (factory setting)
 Standard

To access the insulation alarm relay parameter, select Menu → Settings → I/O Config..

Setting Setting range Factory value

Ins. Al. Relay (insulation alarm relay) FS / STD FS

When the insulation alarm relay is configured in failsafe (FS) mode:

 The insulation alarm relay is activated (energized) in the following case:
 No insulation fault is being detected.

 The insulation alarm relay is deactivated (de-energized) in the following cases:

 Preventive insulation fault is being detected.
 Insulation fault is being detected.
 A special insulation status is detected (see page 61).
 The product is inoperative (detected by self-test).
 The auxiliary power supply is lost.
 Corrected insulation fault signal: the insulation fault relay toggles for 3 seconds when an insulation
fault has been detected, acknowledged, and later corrected in the power system (see page 44).
 When the user triggers a self-test with relays (selecting Menu → Settings → I/O Config. →
Test. w. Relays, set to ON), the insulation alarm relay toggles for 3 seconds (see page 53).

When the insulation alarm relay is configured in standard (Std.) mode:

 The insulation alarm relay is activated (energized) in the following cases:
 A preventive insulation fault is being detected.
 Insulation fault is being detected.
 A special insulation status is detected (see page 61).
 The product is inoperative (detected by self-test).
 Corrected insulation fault signal: the insulation fault relay toggles for 3 seconds when an insulation
fault has been detected, acknowledged, and later corrected in the power system (see page 44).
 When the user triggers a self-test with relays (selecting Menu → Settings → I/O Config. →
Test. w. Relays, set to ON), the insulation alarm relay toggles for 3 seconds (see page 53).
 The insulation alarm relay is deactivated (de-energized) in the following cases:
 No insulation fault is being detected.
 Insulation fault is being detected and acknowledged. Acknowledgement of the insulation alarm relay
is activated (selecting Menu → Settings → I/O Config. → Ack. Al. Relay, set to ON).
 The auxiliary power supply is lost.

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Vigilohm IM400 - Functions

Preventive Insulation Alarm Relay

To access the preventive insulation alarm relay parameter, select Menu → Settings → I/O Config.

Setting Setting range Factory value

Prev. Al. Relay (preventive insulation Std. / FS / Mirror FS
alarm relay)

When the preventive insulation alarm relay is configured in failsafe (FS) mode:
 The preventive insulation alarm relay is activated (energized) in the following case:
 No insulation fault is being detected.

 The preventive insulation alarm relay is deactivated (de-energized) in the following cases:
 Preventive insulation fault is being detected.
 Insulation fault is being detected.
 A special insulation status is detected (see page 61).
 The product is inoperative (detected by self-test).
 The auxiliary power supply is lost.
 When the user triggers a self-test with relays (selecting Menu → Settings → I/O Config. →
Test. w. Relays, set to ON), the preventive insulation alarm relay toggles for 3 seconds
(see page 53).
When the preventive insulation alarm relay is configured in standard (Std.) mode:
 The preventive insulation alarm relay is activated (energized) in the following cases:
 The preventive insulation fault is being detected.
 Insulation fault is being detected.
 A special insulation status is detected (see page 61).
 The product is inoperative (detected by self-test).
 When the user triggers a self-test with relays (selecting Menu → Settings → I/O Config. →
Test. w. Relays, set to ON), the preventive insulation alarm relay toggles for 3 seconds
(see page 53).
 The preventive insulation alarm relay is deactivated (de-energized) in the following cases:
 No insulation fault is being detected.
 The auxiliary power supply is lost.

When the preventive insulation alarm relay is set up in mirror mode (by selecting Menu → Settings →
I/O Config → Prev. Al. Rel → Mirror):
 The preventive insulation alarm relay mirrors (symmetrically matches) the insulation alarm relay as long
as the Vigilohm IM400 is operating correctly (see page 26).
 The preventive insulation alarm relay stops mirroring the insulation alarms when the Vigilohm IM400 is
de-energized or inoperative. This feature can be used to detect an inoperative product.

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 Vigilohm IM400 - Functions

Examples of Application of Preventive Alarm Relay Mirroring Modes

Some applications require that when an IMD device becomes inoperative, the system automatically
switches to another IMD device by managing exclusions using the injection inhibition input (see page 48).
Using the preventive insulation alarm relay configured in mirror mode, the relays can be wired in series
creating a logical AND function. It is recommended to configure the insulation alarm relay in failsafe mode
and wire both relays in (NC/C).
In this case, the logical function returns true only when the device is inoperative or de-energized, or when
a special status is active.
The following wiring diagram is an example of the Vigilohm IM400 wired in Standard mode:

A Preventive insulation alarm (configured in standard mode)

B Insulation alarm (configured in standard mode)

Standard Mode Configuration

Mode Input State

No fault Preventive alarm Alarm Inoperative product No power
Standard PLC 1 1 1 1 0 0
Standard PLC 2 1 1 0 0 1

The following wiring diagram shows how to wire the Vigilohm IM400 in FS mode:

A Preventive insulation alarm (configured in FS mode)

B Insulation alarm (configured in FS mode)

Failsafe (FS) Mode Configuration

Mode Input State

No fault Preventive alarm Alarm Inoperative product No power
FS PLC 1 0 0 0 1 1
FS PLC 2 0 0 1 1 1

ALARM=(RelayState:ON) || ((StatusInput:CLOSED) & (RelayState:OFF))

 An insulation alarm is detected when both PLC inputs are at a logic 1.
 A product failure is detected when PLC input 1 is a logic 0.

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Vigilohm IM400 - Functions

Insulation Alarm Relay Acknowledgement

When the relays are connected to loads (for example, horns or lamps), it is recommended to turn off these
external signaling devices before the insulation level rises back to a level above the setup thresholds. This
can be done by clicking the acknowledge button while in insulation alarm state.
In certain system configurations, it is required to prevent this type of user acknowledgement and only
retrigger the relays when the insulation level rises above the setup thresholds. This is done by changing
the corresponding parameter.
To acknowledge the insulation alarm relay parameter, select Menu → Settings → I/O Config.

Setting Setting range Factory value

Ack. Al. Relay (acknowledgement ON / OFF ON
insulation alarm relay)

When the Vigilohm IM400 detects an insulation fault, both the preventive insulation alarm relay and the
insulation alarm relay are triggered, depending on the setup.
 Acknowledgement of relays set to ON

Insulation fault alarm acknowledgement switches back the relays to their initial position.

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 Vigilohm IM400 - Functions

 Acknowledgement of relays set to OFF

Insulation fault alarm acknowledgement does not switch back the relays to their initial position.

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Vigilohm IM400 - Functions

Corrected Insulation Fault Signal

In order to facilitate insulation fault detection, the insulation alarm relay can be reactivated for 3 seconds
when the insulation level rises above the setup threshold.
This makes it easier to locate the insulation fault when using the method that involves opening each of the
circuit breakers in turn. Given that the circuit breakers may be located at some distance from the Vigilohm
IM400, the external signal allows you to identify and locate the insulation fault when working remotely. This
option can be activated by changing the corresponding parameter.
To access the option, select Menu → Settings → I/O Config.

Setting Setting range Factory value

Corr. Flt Signal (corrected fault ON / OFF OFF
signal)

NOTE: Corrected insulation fault signal is applicable only if the parameter Ack. Al. Relay
(acknowledgement insulation alarm relay) is set to ON.

In system configurations where the insulation alarm relay is connected to an external signaling device (for
example, horns or lamps), the relays are triggered back to their normal position, depending on their setup,
when the insulation alarm is acknowledged.
 Corrected insulation fault signal set to ON

After correcting the insulation fault in the power system, the insulation fault alarm relay toggles for
3 s.

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 Vigilohm IM400 - Functions

 Corrected insulation fault signal set to OFF

After correcting the insulation fault in the power system, the insulation fault alarm relay does not
toggle for 3 s.

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Vigilohm IM400 - Functions

Operation on Systems with a Voltage Greater Than 480 Vac/dc

Operation
A voltage adaptor is required when the device is connected to one of the following systems:
 system voltage greater than 830 Vac Ph-Ph and the Vigilohm IM400 is connected to an accessible
neutral.
 system voltage greater than 480 Vac and the Vigilohm IM400 is connected to a phase (non-accessible
neutral).
 system voltage greater than 480 Vdc.

See the specifications for information about the maximum voltage (see page 84).
For Vigilohm IM400 operation without insulation fault location (XD301, XD312, XD308C, or XRM not used),
the IM400-1700 voltage adaptor can be used.
For Vigilohm IM400 operation with insulation fault location (XD301, XD312, XD308C, or XRM used), the
PHT1000 voltage adaptor must be used.
NOTE: The V. Adaptor parameter cannot be set up as HV1700 if the parameter Fault locating is set to
ON.

V. Adaptor Parameter
Configure the V. Adaptor parameter as follows:
 HV1700 for the IM400-1700 voltage adaptor
 PHT1000 for the PHT1000 voltage adaptor

The factory value is None (operation without voltage adaptor).

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Insulation Fault Location

Locating Insulation Faults Automatically

Vigilohm IM400 is compatible with the XD••• range of insulation fault locators from the Vigilohm offer:
 XD301: one-channel insulation fault locator with indicator light and one output relay (commercial
references 50506, 50507, and 50508)
 XD312: twelve-channel insulation fault locator with one indicator light per channel and one output relay
(commercial references 50535, 50536, and 50537)
 XD308C: eight-channel insulation fault locator with communication (requires an XLI300 communication
interface) (commercial references 50723, 50724, and 50725)
The Insulation Fault Locating parameter must be configured to ON for proper operation. The factory
value is OFF in photovoltaic application, ON for the other applications.

Locating Insulation Faults Manually

From the Vigilohm offer, the mobile insulation fault locating devices must be used for:
 The insulation fault location on a feeder not equipped with an automatic insulation fault locator or
 Facilitating the location of an insulation fault on a feeder.

The Insulation Fault Locating parameter must be configured to ON for proper operation. The factory
value is ON.
The signal injected by IM400 is compatible with the XP15, XP50, XP100, and XRM devices. Proceed as
follows:
1. Use the XRM connected to an XP•• current probe on the injection connection wire close to IM400, and
calibrate the XRM to 18.
2. Use the XRM on the cables to locate the insulation fault. When the XRM is reporting 18, it means that
the insulation fault is on the cable or the load downstream to the clamp.
Refer to the Vigilohm Catalog for information about the mobile insulation fault locating devices:
 XRM locating signal receiver (commercial reference 50278)
 Open-clamp current probes (commercial references 50494, 50498, and 50499)
NOTE: In manual fault location mode with IM400, XGR injector is not necessary.

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Vigilohm IM400 - Functions

Injection Inhibition Input and Exclusion Management

Exclusion
The IMD injects several patented combinations of low frequency voltage into the system. In a system with
several incoming feeders, depending on the circuit breaker position, there must be no more than one IMD
injecting into the system.
The inhibition of injection is managed by the state of inhibition input of Vigilohm IM400, which can, for
example, be connected to the auxiliary contacts of the circuit breakers.
The injection inhibition input can be configured to use an NO or an NC contact as shown below:

Contact type Injection activated when the contact is... Injection deactivated when the contact is...
NO (factory value) Open Closed
NC Closed Open

Example of Exclusion with Two Incoming Feeders

Using circuit breakers with normally open (NO) auxiliary contacts:

Using circuit breakers with normally closed (NC) auxiliary contacts:

If Then
 If D1 is closed and The two Vigilohm IM400 devices are active:
 D2 is open  Vigilohm IM400 no.1 monitors the system insulation.
 Vigilohm IM400 no.2 only monitors the insulation of the transformer 2 connection as far as D2.

 If D1 is open and The two Vigilohm IM400 devices are active:

 D2 is closed  Vigilohm IM400 no.1 monitors the insulation of the transformer 1 connection as far as D1.
 Vigilohm IM400 no.2 monitors the system insulation.

 If D1 is closed and  Vigilohm IM400 no.1 is active and monitors the system insulation.
 D2 is closed  Vigilohm IM400 no.2 must be inhibited.

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Example of Exclusion with Two Incoming Feeders and One Coupling

Using circuit breakers with normally open (NO) auxiliary contacts:

Using circuit breakers with normally closed (NC) auxiliary contacts:

If Then
If the coupling (C) is closed The same applies as in the exclusion example above involving two incoming
feeders (see page 48).
 If the coupling is open and The two Vigilohm IM400 devices are active:
 D1 is closed  Vigilohm IM400 no.1 monitors the insulation of system 1.
 D2 is closed  Vigilohm IM400 no.2 monitors the insulation of system 2.

Vigilohm IM400 no.2 must be inhibited when the following three conditions are met:
 D1 is closed.
 D2 is closed.
 C is closed.

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Example of Exclusion with Three Incoming Feeders

Using circuit breakers with normally open (NO) auxiliary contacts:

Using circuit breakers with normally closed (NC) auxiliary contacts:

The IMD priority is as follows:

 IM400 no.1 is the IMD with the highest priority 1: it always injects into the systems no matter if D1 is
closed or open.
 IM400 no.2 is the IMD with priority 2: it always injects into the system except when there is a closed path
between it and one IMD with a higher priority, that is, in this case IM400 no.1. Therefore, IM400 no.2 is
inhibited when D2 and D1 are closed:
IM400 no.2 injection inhibition = D1 AND D2.
This logic is implemented by wiring the injection inhibition of IM400 no.2 to the 2 auxiliary contacts of
D1 and D2.
 IM400 no.3 is the IMD with priority 3: it always injects into the system except when there is a closed path
between it and one IMD with a higher priority, that is, in this case IM400 no.1 or IM400 no.2. Therefore,
IM400 no.2 is inhibited when D3 and D2 are closed, or D3 and D1 are closed:
IM400 no.3 injection inhibition = (D3 AND D1) OR (D3 AND D2) = D3 AND (D1 OR D2)This logic is
implemented by wiring the injection inhibition of IM400 no.3 to the auxiliary contacts of D1 and D2 and
D3.

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Example of Exclusion with Multiple Incoming Feeders and Couplings

For complex configurations where, there are multiple incoming feeders and couplings, it is required to use
a basic Programmable Logic Controller (PLC) to manage the exclusion of IMD.
The PLC can have the following characteristics:
 Number of digital inputs: is the number of circuit breakers for incoming feeder and for coupling. These
inputs can be self-powered by the PLC or powered by an external power supply.
 Number of digital outputs: is the number of IMDs -1. These digital outputs can be electromechanical or
solid-state outputs.
 Processing cycle is equal to 0.1 s or less.

Using a basic PLC to manage IMD exclusion allows to:

 Monitor continuously each part of IT power system.
 Have a short response time to detect insulation faults.
 Be compatible with complex power systems with high number of incoming feeders and couplings.

There are two methods to determine the logic driving the injection inhibition input of each IMD:
Method 1: Give a priority to each IMD using indexes of incoming feeders. In this example:
 Priority of IM400 no.1 is 1 (highest priority),
 Priority of IM400 no.2 is 2,
 Priority of IM400 no.3 is 3,
 Priority of IM400 no.4 is 4 (lowest priority).

 IM400 no.1 with the highest priority is always injecting, its injection inhibition input is left unwired.
 IM400 no.2 with the priority 2 always injection into the system except when there is a closed path
between itself and one IMD with a higher priority, that is, IM400 no.1 in this case. The closed path occurs
when D2, C1 and D1 are closed.
Therefore:
Injection inhibition of IM400 no2 =
D2 AND C1 AND D1
The representation in Ladder PLC programming language is as follows:

 IM400 no.3 with the priority 3 always injection into the system except when there is a closed path
between itself and one IMD with a higher priority, that is, IM400 no.2 and IM400 no.1 in this case.
The closed path occurs when:
 (D3, C2, and D2) are closed, or
 (D3, C2, C1, and D1) are closed.

Therefore:
 Injection inhibition of IM400 no.3 =
(D3 ANDC2 ANDD2) OR (D3 AND C2 AND C1 AND D1)
 Injection inhibition of IM400 no.3 =
(D3 AND C2) AND (D2 OR (C1 AND D1))

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The representation in Ladder PLC programming language is as follows:

 IM400 no.4 with the priority 4 always injection into the system except when there is a closed path
between itself and one IMD with a higher priority, that is, IM400 no.3, IM400 no.2, and IM400 no.1 in
this case.
The closed path occurs when:
 (D4, C3, and D3) are closed, or
 (D4, C3, C2, and D2) are closed, or
 (D4, C3, C2, C1, and D1) are closed.

Therefore:
 Injection inhibition of IM400 no.4 =
(D4 AND C3 AND D3) OR (D4 AND C3 AND C2 AND D2) OR (D4 AND C3 AND C2 AND C1 AND D1)
 Injection inhibition of IM400 no.3 =
(D4 AND C3) AND (D3 OR (C2 AND D2) OR (C2 AND C1 AND D1))
The representation in Ladder PLC programming language is as follows:

Method 2: Use a truth table.

Possible configurations 1 = Injection inhibition

D1 D2 D3 D4 C1 C2 C3 IM400 IM400 IM400 IM400
no.1 no.2 no.3 no.4
0 0 0 0 0 0 0 0(1) 0(1) 0(1) 0(1)
0 0 0 0 0 0 1 0(1) 0(1) 0(1) 0(1)
...
0 1 1 1 1 0 1 0(1) 0(2) 0(2) 1(3)
...
1 1 1 1 0 0 0 0(2) 0(2) 0(2) 0(2)
...
1 1 1 1 1 1 1 0(2) 1(3) 1(3) 1(3)
(1) Vigilohm IM400 monitors the transformer.
(2) Vigilohm IM400 injects a signal into the system.
(3) Vigilohm IM400 is excluded from the system (injection inhibited).

Injection Inhibition Screen

When the injection inhibition function of Vigilohm IM400 is activated (that is, Inhibit. Input set to N.O.), the
screen below appears and replaces any system status screen that may be showing already (insulation
measurement, insulation alarm, or preventive insulation alarm):

You can perform the following actions on this screen:

 Press the MENU button to access the main menu.
 Press the arrow contextual menu buttons to view the setting screen.

 Press the contextual menu button to launch the self-test.

NOTE: When activating injection again (that is, Inhibit. Input set to N.C.), a self-test is launched
automatically before returning to the default insulation monitoring screen.

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Self-Test

Description
The Vigilohm has a self-test function for testing:
 The product: indicator lights, internal electronics
 The measurement system, and the insulation alarm and preventive insulation alarm relays

Running the Self-Test

The test can be run/runs:
 Manually at any time by pressing the contextual menu button on one of the system insulation
monitoring screens
 Automatically:
 Whenever the device starts up (power-up or reset)
 Every five hours (except when the device is in the insulation alarm status, regardless of whether the
insulation alarm is active or has been acknowledged)
 Whenever leaving the inhibited injection state (Inhibit. Input) when injection is activated again.

Sequence of Indicator Lights

During the verification sequence, the indicator lights light up in the following order:
 Insulation status yellow
 Preventive insulation alarm white
 Insulation status green
 Modbus communication yellow
 Product status red

Test with Relays

Use this setting to select whether to include a three-second toggle of the preventive insulation alarm relay
and insulation alarm relay during a manually launched self-test.
To access the test with relay parameter, select Menu → Settings → I/O Config.

Setting Setting range Factory value

Test w. Relays (test with relays) ON / OFF ON

Self-Test OK
If the self-test is successful, the following screen appears for three seconds:

After that, a measurement phase shown by a progress bar at the bottom of the screen appears, and then
one of the status screens automatically appears (system insulation resistance measurement or insulation
fault alarm).

Self-Test Not OK
If the self-test is not successful, the product automatically restarts. If the problem persists:
 The red status indicator LED switches on.
 The insulation alarm relay is triggered
 A product inoperative message is displayed.

If this happens, briefly disconnect the auxiliary power supply of the Vigilohm. If the problem persists,
contact the Schneider Electric Customer Care Center.

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Vigilohm IM400 - Human Machine Interface
DOCA0049EN-02 09/2015

Chapter 4
Human Machine Interface

Human Machine Interface

Presentation
The Vigilohm features a sophisticated and intuitive human machine interface (HMI) with signaling indicator
lights, a graphic display, and contextual menu buttons for accessing the information required to operate
the Vigilohm and make parameter settings.

What Is in This Chapter?

This chapter contains the following topics:
Topic Page
Vigilohm IM400 Menu Structure 56
Navigating the Interface 57
Status Screens 59
Special Status Screens 61
Modifying Parameters 62
Clock 64
Insulation Fault Log 65
Trend Screens 66

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Vigilohm IM400 Menu Structure

Vigilohm IM400 Menu Structure

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Navigating the Interface

Presentation
The diagram below illustrates the various elements for operating the Vigilohm.

1 Screen identification area containing a menu icon, and the name of the menu or parameter
2 Information area for displaying screen-specific details (measurement, insulation alarm, setting)
3 Navigation buttons

Navigation Buttons
The navigation buttons enable quick and intuitive navigation:

Legend Button Icon Description

1 MENU – Displays the level 1 main menu
2 ESC – Takes you back to the previous level
3 Contextual menu For scrolling up the display or moving to the previous item in a
button 3 list
For accessing the date and time setting
If the clock icon flashes, it means that the Date/Time parameter
needs to be set.
For increasing a numerical value

4 Contextual menu For scrolling down the display or moving to the next item in a list
button 2
For moving one digit to the left within a numerical value. If the
digit on the far left is already selected, pressing the button loops
you back to the digit on the right.
For moving 1 digit to the right within a numerical value

5 Contextual menu For validating the selected item

button 1
For executing the manual test

For accessing a menu or submenu, or for editing a parameter

For acknowledging insulation alarms

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Information Icons
This table describes the icons provided for information in the information area of the LCD display. Among
other things, they indicate which menu is selected or the insulation alarm status.

Icon Description
Main menu

 Identifies the system resistance when there is no insulation fault

 Measurement parameter menu

Insulation fault log menu

Trend menu

Setting parameter menu

Interface language selection menu

Product identification

Indicates an insulation fault alarm or preventive insulation alarm

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Status Screens

Presentation
The default screen shows the insulation resistance value of the system. This screen is automatically
replaced by an alert screen when an insulation alarm occurs.
The screen backlight flashes to indicate an insulation alarm.
Each insulation measurement screen displays a status bar at the bottom that provides additional
information. In general, it shows the date and time of the insulation fault.

1 Insulation value
2 Progress bar for the refresh time
3 Bargraph indicating the insulation level on a logarithmic scale. The symbol indicates the insulation
alarm threshold value.
4 Status bar displaying additional information related to the current insulation alarm state. Different types
of status bar are available (see note below).
5 Contextual buttons for navigating the insulation screens or for launching a manual self-test.
NOTE: The different types of status bar are:
 Current date and time: displayed when product is in normal operation (no insulation fault detected)
 Insulation alarm active time delay: an insulation fault has been measured and the insulation alarm time
delay is active. This bar shows a progress bar for the time delay.
 Insulation alarm pickup date and time
 Insulation alarm dropout date and time
 Insulation alarm relay acknowledgment

The bars can also indicate:

 a cyclic self-test is running in the background
 a first measurement is in progress (at startup or after reactivating the injection function)

System Insulation Resistance Measurement (R)

The Vigilohm displays the insulation resistance measurement for the system by default. The status bar
shows the current time of the IMD.

Insulation Alarm Detected: Insulation Fault Message

The following screen displays when the insulation value drops below the insulation alarm threshold:

There are 2 possible scenarios:

 Acknowledge the insulation alarm by pressing the contextual menu button.
 If you do not acknowledge the insulation alarm and the system insulation returns to a value above the
insulation alarm threshold, this results in a transient insulation fault.

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Insulation Alarm Acknowledged

The following screen appears once the insulation alarm is acknowledged. The status bar shows the time
when the insulation fault is acknowledged.

Preventive Insulation Alarm Activated

The following screen appears when the preventive insulation alarm is activated:

Transient Insulation Fault Message

The following screen appears in the event of a transient insulation fault:

Acknowledge the transient insulation fault by pressing the contextual menu button.

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Special Status Screens

Presentation
The special status screens are displayed depending on events that occur during the product life. The
screens depend on the event type but always trigger the red product status indicator light and the insulation
alarm relay is active. If the preventive insulation alarm relay is configured in mirror mode, it is also triggered
and no longer mirrors the insulation alarm relay.

Over-Limit Capacitance Detection

The over-limit capacitance detection state is triggered when the capacitance of the monitored system
becomes too high. For details on the Vigilohm IM400 limits, refer to the product performances. In case of
detected over-limit capacitance, the Vigilohm IM400 is no longer able to monitor the IT system.

Power Circuit or Control Circuit Photovoltaic Circuit

Overvoltage
The overvoltage state is triggered when the voltage of the monitored system becomes too high. For details
on the Vigilohm IM400 limits, refer to the product performances. In case of overvoltage, the Vigilohm IM400
is no longer able to monitor the IT system and automatically disconnects of the power system until the
product is manually reset by briefly disconnecting the auxiliary power supply.

Disconnected Injection Detection

The state of disconnected injection is triggered when the Vigilohm IM400 detects that the ground conductor
or the injection wire is disconnected. In case of disconnected injection detected, the Vigilohm IM400 is no
longer able to monitor the IT system.
If the Disconnect Inj. parameter in the Ins. Alarm menu is set to ON, the following screen displays:

If the Disconnect Inj. parameter is set to OFF, the Vigilohm IM400 displays R > 10 MΩ.

Inoperative Product
The inoperative product state is triggered when the Vigilohm IM400 is inoperative.

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Modifying Parameters

Presentation
To modify any of the values, you must be familiar with how the interface menus are structured and the
general navigation principles. For more information about how the menus are structured, refer to the
Vigilohm IM400 menu structure (see page 56).
To modify the value of a parameter, follow either of the two methods described below:
 Select an item (value plus unit) in a list.
 Modify a numerical value, digit by digit.

The parameters listed below are the only ones where the numerical value can be modified:
 date
 time
 password
 Modbus address

Selecting the Value in a List

To select a value in a list, use the or contextual menu buttons to scroll through the parameter values
until you reach the desired value. Then press to confirm the new parameter value.

Modifying the Numerical Value

The numerical value of a parameter is made up of digits and it is the one on the far right that is selected by
default.
To modify a numerical value, use the contextual menu buttons as described below:
 allows you to modify the selected digit.
 allows you to select the digit to the left of the one that is selected, or to loop back to the digit on the
right.
 confirms the new parameter value.

Saving a Parameter
After you have confirmed the modified parameter, one of the two screens appears:
 If the parameter has been saved correctly, the screen displays Saved and then automatically reverts to
the previous display.
 If the parameter has not been saved correctly, the screen displays Error and the editing screen remains
active. It happens when:
 a value is deemed to be out of range (for example the value is classed as forbidden),
 there are several interdependent parameters.

Exiting an Entry
To exit the current parameter entry, press the ESC button. The screen reverts to the previous display.

Editing Protected Settings

You can set a password to limit access to configuration of Vigilohm IM400 parameters to authorized
personnel only. When a password has been set, the information displayed by the device can be viewed
but the parameter values cannot be edited.
The password is inactive by default. When password protection is enabled, the default password is 0000.
If you want to change the factory value, you must enter a 4-digit password from 0000 to 9999 when editing
a parameter.
The procedure for setting a password is the same as editing a numerical value.

Step Action
1 Navigate to MENU → Settings → Password.
2
Select Modify Password. Press to edit the new password digit by digit (editing starts from the digit
furthest to the right).
3
Use to increase the value of the digit. It will automatically roll over from 9 to 0.

NOTE: Keep the button pressed down to accelerate scrolling through the values.

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Step Action
4
Press to move to the next digit. Pressing this button on the last digit (furthest left) loops you back to
the first one.
5 Repeat steps 3 and 4 for all other digits.
6
Press to save the new password. A message indicates that the password was saved successfully.
The screen reverts to the previous one.
7
Select Activation. Press .
8
Change value list to ON by pressing the or arrows. Validate the entry by selecting . A message
indicates that the parameter was saved successfully.
Result: The password protection is now active.

The procedure for entering a password is similar to editing a numerical value.

Step Action
1 Press the contextual menu navigation keys to navigate to the parameter to edit.
2
Press . The screen to enter the password is displayed.
The first (furthest left) digit is selected and ready to edit.
3
Use to increase the value of the digit. It will automatically roll over from 9 to 0.

NOTE: Keep the button pressed down to accelerate scrolling through the values.
4
Press to move to the next digit. Pressing this button on the last digit (furthest right) loops you back to
the first one.
5 Repeat steps 3 and 4 for all other digits.
6
Press to validate the password entry. If the password has been entered correctly, the protection
system stays unlocked for 30 seconds or as long as you are editing parameters.
If the password has been entered incorrectly, an error message is displayed and you must enter the
password again. Use the ESC button to revert to the previous screen.

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Clock

Description
Vigilohm IM400 uses the date and time parameter to time-tag the system insulation faults recorded.
The time must be set:
 whenever the power supply is interrupted,
 when switching from winter to summer time and back.

If the auxiliary power supply is interrupted, Vigilohm IM400 retains the date and time setting from
immediately before the interruption.

Icon
When Vigilohm IM400 is powered up, the clock icon flashes on the system monitoring screens to indicate
that the clock needs to be set.
Pressing the top contextual button displays the clock setup screen.

Setting
To set the date and time, refer to the procedure for modifying a numerical value (see page 62).

Date/Time Format
The date is displayed in the format: dd.mm.yyyy.
The time is displayed using the 24-hour clock in the format: hh:mm.

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Insulation Fault Log

Description
Vigilohm IM400 records the details of the 30 most recent insulation fault events that have triggered one of
the 2 statuses below:
 preventive insulation alarm
 insulation alarm

Event 1 is the one that was recorded most recently and event 30 is the oldest recorded event.
The oldest event is deleted when a new event occurs. Due to the rolling buffer the Vigilohm IM400 may
show 28 logs maximum. To reset all the events, select Settings → Reset → Reset Logs.
Using this information, the performance of the distribution system can be improved and maintenance work
facilitated. It is also available through Modbus (see page 67).

Insulation Fault Event Screen

The figure below shows the display elements associated with an insulation fault event:

Legend Description
1 Insulation fault value recorded
2 Type of insulation fault recorded: insulation alarm, preventive insulation alarm, transient insulation
alarm
3 Date and time when the insulation alarm fault, preventive insulation alarm, or transient insulation
fault occurred
4 Date and time when the event disappeared:

 Insulation alarm acknowledgment

 Disappearance of preventive insulation alarm or transient insulation alarm

5 Number of events displayed
6 Total number of events recorded

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Trend Screens

Presentation
Vigilohm IM400 records and can display curves of the average of the system insulation over the following
durations:
 last hour (1 point every 2 minutes)
 last day (1 point per hour)
 last week (1 point per day)
 last month (1 point per day)
 last year (1 point per month)

The chart scale automatically adjusts to the shown data to optimize the display accuracy.
The curves show a general trend how the system insulation evolves over time. They are calculated from
averages related to shorter or longer durations depending on the charts. So charts may not show transient
insulation faults when they are smoothed over time.

Trend Screen

Legend Description
1 Trend
2 Current value of the insulation alarm threshold
3 Vertical dotted line: indicates a power interruption (duration undefined)
4 Squared area: indicates that the injection has been inhibited

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Vigilohm IM400 - Communication
DOCA0049EN-02 09/2015

Chapter 5
Communication via Modbus RS-485

Communication via Modbus RS-485

What Is in This Chapter?

This chapter contains the following topics:
Topic Page
Configuring RS-485 Communication Port 68
Table of Modbus Functions 69
Modbus Registers Tables 70

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Configuring RS-485 Communication Port

Communication Parameters
Before initiating any communication processes, configure the Modbus communication port via the HMI on
Vigilohm IM400 selecting Menu → Settings → Modbus.

Parameters Authorized values Factory value

Address 1...247 1
Auto Config ON / OFF OFF
Baud rate  4800 Baud 19 200 Baud
 9600 Baud
 19 200 Baud
 38 400 Baud
Parity  Even Even
 Odd
 None

In point-to-point mode, when the device is directly connected to a computer, the reserved address 248 can
be used to communicate with the device whatever the device internal address.

Signaling of Communication Activity

The yellow indicator light indicates the status of the activity on the Modbus RS-485 bus as follows:

If Then
If the indicator light is flashing Communication on the bus is active.
If the indicator light is off There is no active communication between master and slave.

NOTE: The yellow indicator light flashes on every valid Modbus frame even if the Vigilohm IM400 is not
addressed directly.

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Table of Modbus Functions

Modbus Functions

Function code Function name

Decimal Hexadecimal
3 0x03 Read Holding Registers(1)
4 0x04 Read Input Registers(1)
6 0x06 Write Single Register
8 0x08 Diagnostics
16 0x10 Write Multiple Registers
67 / 14 0x43 / 14 Read Device Identification
67 / 15 0x43 / 15 Get Date/Time
67 / 16 0x43 / 16 Set Date/Time
(1) The Read Holding and Read Input registers are identical

The read device identification request is as follows:

Number Type Value

0 VendorName Schneider Electric
1 ProductCode IM400
2 MajorMinorRevision vX.Y.Z
3 VendorURL www.schneider-electric.com
4 ProductName Insulation Monitoring Device
5 ModelName IM400

The product answers any types of requests (basic, regular, extended).

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Modbus Registers Tables

Table Format
Modbus register tables have the following columns:

Address Register number RW Unit Type Range Description

hex dec hex dec

 Register address: Address of register encoded in the Modbus frame, in hexadecimal (hex) and decimal
(dec) formats
 Register number: corresponds to the Register Address + 1, in hexadecimal (hex) and decimal (dec)
formats
 RW: Whether the register is read only (R) or read/write (RW)
 Unit: The unit the information is expressed in
 Type: The encoding data type
 Range: The permitted values for this variable, usually a subset of what the format allows
 Description: Provides information about the register and the values that apply

System Status

Address Register number RW Unit Type Range Description

hex dec hex dec
0x0064 100 0x0065 101 R – Uint16  17000 - IM10 Device identifier
 17001 - IM10H
 17002 - IM20
 17003 - IM20H
 17004 - IM400
0x0066... 102...103 0x0067...0x0068 103...104 R – Uint16 Encoded version Firmware version X.Y.Z:
0x0067 X.Y.Z  X represents the primary revision
number, which is encoded in the
most significant byte of register
102.
 Y represents the secondary
revision number, which is encoded
in the least significant byte of
register 102.
 Z represents the quality revision
number, which is encoded in
register 103.
0x0069... 105...108 0x006 A...0x006D 106...109 RW – – – Date/Time (TI081 format
0x006C (see page 77))
0x006D 109 0x006E 110 R – Uint16 – Product status:
 Most significant byte = error code
 Least significant byte = product
status
 0x00 - Normal operation
 0x01 - Self-test
 0x02 - Insulation fault
 0x03 - Disconnected injection
detected
 0x04 - Over-limit capacitance
 0x05 - Inoperative product
 0x06 - Injection disabled
 0x07 - Overvoltage

Monitoring

Address Register number RW Unit Type Range Description

hex dec hex dec
0x03E8 1000 0x03E9 1001 R Ohm Float32 – Resistance.
When injection is inhibited, the
value NaN (Not a Number)
0xFFC00000 is returned during
self-test.

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Address Register number RW Unit Type Range Description

hex dec hex dec
0x03EA 1002 0x03EB 1003 R F Float32 – Capacitance.
When injection is inhibited, the
value NaN (Not a Number)
0xFFC00000 is returned during
self-test.
0x03F0 1008 0x03F1 1009 R – Uint16  0 = Injection Injection status
activated
 1 = Injection
deactivated

Insulation Alarm Status

Address Register number RW Unit Type Range Description

hex dec hex dec
0x044C 1100 0x044D 1101 R – Uint16  0 = No Insulation alarm status
insulation
alarm
 1 = Insulation
alarm active
 2 = Preventive
insulation
alarm active
 4 = Transient
insulation
alarm
 8 = Insulation
alarm
acknowledged

Trending Data

Address Register number RW Unit Type Range Description

hex dec hex dec
0x04B0 1200 0x04B1 1201 R – Uint16 Hour trending Number of new records in trending
buffer not yet read by the Modbus
master
0x04B1 1201 0x04B2 1202 R – Uint16 Day trending Number of new records in trending
buffer not yet read by the master
0x04B2 1202 0x04B3 1203 R – Uint16 Week trending Number of new records in trending
buffer not yet read by the master
0x04B3 1203 0x04B4 1204 R – Uint16 Month trending Number of new records in trending
buffer not yet read by the master
0x04B4 1204 0x04B5 1205 R – Uint16 Year trending Number of new records in trending
buffer not yet read by the master
0x04BA 1210 0x04BB 1211 R – Float32 Hour value Reading hour values.
Each reading decrements the
counter at address 1200.
0x04BC 1212 0x04BD 1213 R – Uint16 Hour value status Status:
 0x0000 - Data not initialized
 0x0001 - Data invalid
 0x0002 - Data valid
 0x0003 - Power supply loss
after this value
 0x0004 - Injection after this
value
 0x0005 - Power supply loss
and injection disable after this
value

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Address Register number RW Unit Type Range Description

hex dec hex dec
0x04BD 1213 0x04BE 1214 R – Float32 Day value Reading day values.
Each reading decrements the
counter at address 1201.
0x04BF 1215 0x04C0 1216 R – Uint16 Day value status Status:
 0x0000 - Data not initialized
 0x0001 - Data invalid
 0x0002 - Data valid
 0x0003 - Power supply loss
after this value
 0x0004 - Injection disable after
this value
 0x0005 - Power supply loss
and injection disable after this
value
0x04C0 1216 0x04C1 1217 R – Float32 Week value Reading week values.
Each reading decrements the
counter at address 1202.
0x04C2 1218 0x04C3 1219 R – Uint16 Week value Status:
status  0x0000 - Data not initialized
 0x0001 - Data invalid
 0x0002 - Data valid
 0x0003 - Power supply loss
after this value
 0x0004 - Injection disable after
this value
 0x0005 - Power supply loss
and injection disable after this
value
0x04C3 1219 0x04C4 1220 R – Float32 Month value Reading month values.
Each reading decrements the
counter at address 1203.
0x04C5 1221 0x04C6 1222 R – Uint16 Month value Status:
status  0x0000 - Data not initialized
 0x0001 - Data invalid
 0x0002 - Data valid
 0x0003 - Power supply loss
after this value
 0x0004 - Injection disable after
this value
 0x0005 - Power supply loss
and injection disable after this
value
0x04C6 1222 0x04C7 1223 R – Float32 Year value Reading year values.
Each reading decrements the
counter at address 1205.
0x04C8 1224 0x04C9 1225 R – Uint16 Year value status Status:
 0x0000 - Data not initialized
 0x0001 - Data invalid
 0x0002 - Data valid
 0x0003 - Power supply loss
after this value
 0x0004 - Injection disable after
this value
 0x0005 - Power supply loss
and injection disable after this
value

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Diagnostic

Address Register number RW Unit Type Range Description

hex dec hex dec
0x07D0 2000 0x07D1 2001 W – Uint16 – Write 0xA456 to start self-test
0x07D1... 2001...2004 0x07D2... 2002...2005 R – – – Total uptime since first power-
0x07D4 0x07D5 up of product.
Registers correspond to (result -
01/01/2000) = total uptime.
TI081 date format
(see page 77).
0x07D5 2005 0x07D6 2006 R – Uint32 – Total number of power cycles
since first power-up of the
product
0x0802 2050 0x0803 2051 W – Uint16 – Write 0x1919 to reset factory
settings (default factory
settings)
0x0803 2051 0x0804 2052 W – Uint16 – Write 0xF0 A1 to reset all logs
0x0804 2052 0x0805 2053 W – Uint16 – Write 0x25AB to reset all graphs

Settings

Address Register number RW Unit Type Range Description

hex dec hex dec
0x0BB7 2999 0x0BB8 3000 R – Uint16 – Total number of settings
changed since first power-up.
Incremented by 1 for each
change of one or several
parameters.
0x0BB8 3000 0x0BB9 3001 RW – Uint16  0 = Normally Injection inhibition input
open configuration.
 1 = Normally Factory value: 0 (Normally
closed open).
0x0BB9 3001 0x0BBA 3002 RW – Uint16  1 = Standard Insulation alarm relay logic
connection command.
 2 = Failsafe Factory value: 2 (Failsafe).
0x0BBA 3002 0x0BBB 3003 RW Ohm Uint32 40 Ω...500 kΩ Insulation alarm threshold.
Factory value: 1 kΩ.
0x0BBC 3004 0x0BBD 3005 RW Ohm Uint32  1 kΩ...1 MΩ Preventive insulation alarm
 0xFFFFFFFF = threshold.
OFF OFF is used to deactivate the
preventive insulation alarm.
Factory value: 0xFFFFFFFF
(Deactivated).
0x0BBF 3007 0x0BC0 3008 RW s Uint16 0...7200 Insulation alarm time delay.
Factory value: 0.
0x0BC0 3008 0x0BC1 3009 RW s Uint16  0 = Short (4 s) Network filtering.
 1 = Medium Factory value: 1 (40 s).
(40 s)
 2 = Long
(400 s)
0x0BC1 3009 0x0BC2 3010 RW Hz Uint16  0 (for DC System frequency.
system) Factory value: 50 Hz.
 50
 60
 400

0x0BC6 3014 0x0BC7 3015 RW – Uint16 0000...9999 Password.

Factory value: 0000.
0x0BC7 3015 0x0BC8 3016 RW – Uint16  0 = OFF Password protection.
 1 = ON Factory value: 0 (password
protection deactivated).

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Address Register number RW Unit Type Range Description

hex dec hex dec
0x0BC8 3016 0x0BC9 3017 RW – Uint16  0 = English Interface language.
 1 = French Factory value: 0 (English).
 2 = Spanish
 3 = Russian
 4 = Chinese
 5 = Italian
 6 = German
 7 = Portuguese
0x0BC9 3017 0x0BCA 3018 RW % Uint16 10...100 Display contrast.
Factory value: 50.
0x0BCA 3018 0x0BCB 3019 RW % Uint16 10...100 Display brightness.
Factory value: 100.
0x0BCB 3019 0x0BCC 3020 RW – Uint16  0 = None Voltage adaptor.
 1 = HV1700 Factory value: 0 (no plate).
IM400
 2 = PHT1000

0x0BCC 3020 0x0BCD 3021 RW – Uint16  1 = Standard Preventive insulation alarm

connection relay logic command.
 2 = Failsafe Factory value: 2 (failsafe).
 3 = Mirror

0x0BCD 3021 0x0BCE 3022 RW s Uint16 0...7200 Preventive insulation alarm

time delay
0x0BCE 3022 0x0BCF 3023 RW – Uint16  0 = OFF Insulation alarm relay
 1 = ON reactivation.
Factory value: 0.
ON = relay triggers 3 s if
insulation fault disappears in
insulation alarm
acknowledgement mode
0x0BCF 3023 0x0BD0 3024 RW – Uint16  0 = OFF Insulation alarm relay
 1 = ON acknowledgement.
Factory value: 1.
0x0BD0 3024 0x0BD1 3025 RW – Uint16  0 = Min (15 V) Injection voltage.
 1 = Low (33 V) Factory value: 2.
 2 = Medium
(120 V)
 3 = Max
(150 V) (only
with IM400-
1700 voltage
adaptor)
0x0BD1 3025 0x0BD2 3026 RW – Uint16  0 = Power Customer application.
(Industry) Factory value: 0.
 1 = Control
circuits
 2=
Photovoltaic
0x0BD2 3026 0x0BD3 3027 RW – Uint16  0 = ON Disconnected injection
 1 = OFF detection.
Factory value: 0.
0x0BD3 3027 0x0BD4 3028 RW – Uint16  0 = OFF Insulation fault locating.
 1 = ON Factory value: 0.
0x0BD5 3029 0x0BD6 3030 RW – Uint16  0 = OFF Self-test: test with relays.
 1 = ON Factory value: 1.
0x0BD6 3030 0x0BD7 3031 RW Ω Uint16  0.1...500 kΩ Grounding resistance for
 0xFFFFFFFF = impedant IT systems (HRG).
OFF Factory value: 0xFFFFFFFF
(disabled).

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Log

Address Register number RW Unit Type Range Description

hex dec hex dec
0x4E20 20000 0x4E21 20001 R – Uint16 1...60 Number of event records
0x4E21 20001 0x4E22 20002 R – Uint16 – Number of the most recent
record
0x4E22... 20002... 0x4E23... 20003... R – Record – Record 1
0x4E2D 20013 0x4E2E 20014
0x4E2E... 20014... 0x4E2F... 20015... R – Record – Record 2
0x4E39 20025 0x4E3 A 20026
...
0x50E6... 20710... 0x50E7... 20711... R – Record – Record 60
0x50F1 20721 0x50F2 20722

Each event is stored using two records:

 A primary record, which is created when the insulation alarm or preventive insulation alarm occurs. This
contains the insulation value.
 A secondary record, which is created when the insulation alarm or preventive insulation alarm
disappears. This contains the type of event (acknowledged insulation alarm, transient insulation alarm,
preventive insulation alarm).
The two records are logged consecutively.

Description of an Event Record in the Log

Register Unit Type Range Description

Word 1 – Uint16 1…65535 Event record number
Word 2 – Uint64 – Time tagging of event (using the same code as for
Word 3 the product date/time)
Word 4
Word 5
Word 6 – Uint32  0...1 Record identifier:
Word 7  0x40, 0x10  Word 6, most significant byte: Information for
 1000, 1100 primary/secondary record. This field assumes a
value of 1 for the primary record and a value of 0
for the secondary record.
 Word 6, least significant byte: Type of data stored
in the Value field
 Word 7: Address of the Modbus register that is
the source of the data in the Value field
Word 8 – Uint64 – Depending on the type of record (primary or
Word 9 secondary):
Word 10  Insulation resistance value (in ohms) at the time
Word 11 of the event occurrence (encoded in Float32 in
the last two registers)
 Insulation alarm type (encoded in Uint16 in the
last register)
Word 12 – Uint16 1...65534 Primary/secondary record identifier for event:
 In the case of a primary record for an event, this
identifier is an odd integer; numbering starts at 1
and the number is incremented by 2 for each new
event.
 In the case of a secondary record for an event,
this identifier is equal to the primary record
identifier plus 1.

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Example of an Event
The two records below represent an insulation alarm that occurred at 12:00 on October 1, 2010 and was
acknowledged at 12:29.
Record number: 1

Address Register number Unit Type Value Description

hex dec hex dec
0x4E22 20002 0x4E23 20003 – Uint16 1 Record number
0x4E23 20003 0x4E24 20004 – Uint64  10 Date when insulation alarm occurred
 0 (October 1, 2010, 12:00)
 10
 1
 12
 0
 0
0x4E27 20007 0x4E28 20008 – Uint32  1 Record identifier:
 0x40  Primary record plus secondary
 1000 record
 Float32 value (insulation
resistance)
 Value of register 1000 (register for
insulation resistance monitoring)
0x4E29 20009 0x4E2 A 20010 Ohm Uint64 10000 Insulation resistance value at the time
of the insulation alarm
0x4E2D 20013 0x4E2E 20014 – Uint16 1 Secondary record identifier for event

Record number: 2

Address Register number Unit Type Value Description

hex dec hex dec
0x4E2E 20014 0x4E2F 20015 – Uint16 2 Record number
0x4E2F 20015 0x4E30 20016 – Uint64  10 Date when insulation alarm
 0 disappeared (October
 10 1, 2010, 12:29)
 1
 12
 29
 0
0x4E33 20019 0x4E34 20020 – Uint32  1 Record identifier:
 0x10  Secondary record
 1100  Uint16 value (insulation alarm
acknowledged)
 Value of register 1100 (insulation
alarm status register)
0x4E35 20021 0x4E36 20022 – Uint64 8 Value of insulation alarm register at
the time of insulation alarm
acknowledgement
0x4E39 20025 0x4E3 A 20026 – Uint16 2 Secondary record identifier for event

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Date and Time

The following structure is used for date-time information exchange using Modbus protocol.
The date/time are encoded in 8 bytes as follows:

b15 b14 b13 b12 b11 b10 b09 b08 b07 b06 b05 b04 b03 b02 b01 b00 Word
0 0 0 0 0 0 0 0 R4 Y Y Y Y Y Y Y Word 1
0 0 0 0 M M M M WD WD WD D D D D D Word 2
SU 0 0 H H H H H iV 0 mn mn mn mn mn mn Word 3
ms ms ms ms ms ms ms ms ms ms ms ms ms ms ms ms Word 4

 R4: Reserved bit (reserved by IEC870-5-4), set to 0

 Y - Years
 1 byte
 Value from 0...127 (1/1/2000 to 31/12/2127)

 M - Months
 1 byte
 Value from 1...12

 D - Days
 1 byte
 Value from 1...31

 H - Hours
 1 byte
 Value from 0...23

 mn - Minutes
 1 byte
 Value from 0...59

 ms - Milliseconds
 2 byte
 Value from 0...59999

The following fields are in CP56Time2a standard and are considered as optional:
 WD - Week Day
 If not used, set to 0 (1 = Sunday, 2 = Monday...)
 Value from 1...7

 SU - Summertime
 If not used, set to 0 (0 = standard time, 1 = summertime)
 Value from 0...1

 iV - Validity of the information contained in the structure

 If not used, set to 0 (0 = valid, 1 = not valid or not synchronized in system)
 Value from 0...1

This information is encoded in binary form.

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Vigilohm IM400 - Commissioning, Maintenance, and Troubleshooting
DOCA0049EN-02 09/2015

Chapter 6
Maintenance and Troubleshooting

Maintenance and Troubleshooting

What Is in This Chapter?

This chapter contains the following topics:
Topic Page
Safety Precautions 80
Commissioning 81
Maintenance and Troubleshooting 82

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Safety Precautions

Safety Precautions
The following safety precautions must be thoroughly implemented before commissioning or attempting to
repair electrical equipment or carry out maintenance. Carefully read and follow the safety precautions
described below.

DANGER
HAZARD OF ELECTRIC SHOCK, ARC FLASH OR BURNS
 Wear suitable personal protective equipment and follow the currently applicable electrical safety
instructions. See, for example, standard NFPA 70E when carrying out work in the USA.
 Only qualified personnel should maintain this equipment. Such work should be performed only after
reading all the installation instructions.
 Turn off all power supplying this equipment before working on or inside it.
 NEVER work alone.
 Beware of potential hazards and wear personal protective equipment.
Failure to follow these instructions will result in death or serious injury.

NOTICE
HAZARD OF PRODUCT DAMAGE
 Never open the Vigilohm unit.
 Do not attempt to repair any components in the Vigilohm range, either in the unit or an accessory.
Failure to follow these instructions can result in equipment damage.

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Commissioning

Validating Correct Insulation Monitoring With Exclusion Management

In order to have proper insulation monitoring of the electrical power system, it is important that it is
monitored by one and only one insulation monitoring device at a time.
For most of the systems that do not include multiple incomers or coupling of multiple busbars this is easily
achieved as there is only one IMD in the system permanently active.
For systems with multiple incomers or power busbar coupling, the monitoring system embeds several
Vigilohm IMDs as explained in the Injection Inhibition Input and Exclusion Management section
(see page 48). The exclusion/activation of each IMD according to the electrical power system configuration
is managed through the injection inhibit contact. It is then important at commissioning to validate that
insulation of every part of the electrical power system is monitored by an active IMD, and that the
management of exclusion/activation of each IMD does not lead to a part of the power system monitored
by more than one IMD or by no IMD. This in order to avoid insulation fault not being reported.

Insulation Metering and Insulation Fault Detection Testing

To verify that Vigilohm IM400 is correctly installed and configured:
 It is recommended to check the installation by connecting a known impedance between wiring
terminals 1 and 3 of the Vigilohm IM400 (10 kΩ) and verifying that the impedance is correctly measured.
For this test, do not connect Vigilohm IM400 to the monitored network.
 It is recommended to check the insulation fault detection by strapping wiring terminals 1 and 3 of
Vigilohm IM400 (creating a 0 Ω insulation fault).
For this test, do not connect Vigilohm IM400 to the monitored network.

Insulation Alarm Relay Wiring Testing

To check that the insulation alarm relay is correctly wired in the installation, it is recommended to perform
a device test with relay.

Disconnected Injection Detection

If required in the application enable the disconnected injection detection parameter so that Vigilohm IM400
continuously performs this checking, and reports any connection or wiring issue.
The Vigilohm IM400 is delivered with the disconnected injection detection parameter set to OFF. This
setting helps avoiding an undesired Disconnected Injection Detected message from appearing when
installing and commissioning the device before connecting it to the power system and loads.
According to the system or application requirements, it may be needed to enable the disconnected
injection detection parameter (setting it to ON) when executing the final commissioning. Thus the Vigilohm
IM400 can continuously perform this checking during operation and report any injection connection or
wiring issue.

HV1/HV2 Wiring Testing

The connection between Vigilohm IM400 and the voltage adaptors IM400-1700 or PHT1000 is key for a
correct behavior of IM400.
It is recommended to check the wiring of HV1 and HV2 wiring terminals to the voltage adaptor. It can be
done by connecting a known impedance (for example, 10 kΩ) between IM400-1700 wiring terminal 1 and
IM400 wiring terminal 3, or between PHT1000 wiring terminal 3 and Vigilohm IM400 wiring terminal 3.
Check that Vigilohm IM400 correctly measures.
For this test, do not connect IM400-1700 or PHT1000 to the monitored power system.

Protection Password Setting

To avoid any unintended operation by not authorized or untrained personnel, it is recommended to set the
protection password.

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Maintenance and Troubleshooting

Product Status Indicator Light

The red product status indicator light indicates an error relating to one of the following:
 interruption of the injection circuit
 self-test not OK
 inoperative product
 over-limit capacitance (C > 500 µF or C > 2,000 µF in photovoltaic mode)

Interruption of the Injection Circuit

If the injection circuit of the Vigilohm is interrupted, the display shows the message below and starts
flashing:

Self-Test
The Vigilohm performs a series of self-tests on start-up, and then at regular intervals during operation to
detect any potential inoperations in its internal and external circuits. For more information on the self-test
function, refer to the relevant section (see page 53).

Troubleshooting
The table describes the potential problems and their probable causes. It also indicates the checks that can
be carried out or provides possible solutions for each scenario. If you are still unable to resolve a problem
after consulting the table, contact your Schneider Electric regional sales representative for assistance.

Potential Problem Probable Cause Possible Solution

The device displays nothing when The device is not being supplied. Check the auxiliary supply is present.
switched on.
The auxiliary supply does not comply. Check the value of the auxiliary voltage:
U = 110...480 Vac.
The device signals an insulation fault, The insulation fault alarm threshold is not Check the value of the insulation alarm
but your system shows no signs of appropriate. threshold. Modify the insulation alarm threshold
abnormal behavior. if necessary.
The preventive insulation fault alarm threshold is Check the value of the preventive insulation
not appropriate. alarm threshold. Modify the preventive insulation
alarm threshold if necessary.
You deliberately create an insulation The resistance value used to simulate the Use a resistance value that is lower than the
fault, but the device does not detect it. insulation fault is greater than the value of the insulation alarm threshold or modify the
fault threshold. insulation alarm threshold.
The insulation fault is not detected between Start again verifying that you are between
neutral and ground. neutral and ground.
The product status indicator light is red The Vigilohm injection circuit is cut off.  Check the connection on the injection
and the display shows Disconnected The power system being small, the Vigilohm terminal block (wiring terminals 1 and 3) and
Injection Detected. restart the self-test.
IM400 interprets the low capacitance and high
 Disable the function during the
resistance of the power system as a
disconnected injection. commissioning.

The product status indicator light is red The Vigilohm injection circuit is cut off. Briefly disconnect the auxiliary power supply for
and the display indicates that an error the Vigilohm.
occurred during the self-test.
Although the Vigilohm is being supplied Inoperative indicator light. Restart the self-test and check that the product
with power, the product status indicator status indicator light lights up briefly.
light does not light up.
The insulation alarm indicator light does Inoperative indicator light. Restart the self-test and check that the insulation
not light up in the event of an insulation alarm indicator light lights up briefly.
fault.

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Vigilohm IM400 - Specifications
DOCA0049EN-02 09/2015

Chapter 7
Specifications

Specifications

Specifications

Type of Installation to Be Monitored

Characteristic Values
AC or mixed Phase-to-phase voltage ≤ 830 Vac(1)(2) or
AC/DC IT systems (1) with IM400 connected to neutral
≤ 1,700 Vac(3)
With IM400 connected to phase ≤ 480 Vac(1)(2) or
≤ 1,000 Vac(3)
Frequency 45...440 Hz
DC or rectified systems Line voltage < 480 Vdc(1)(2) or
≤ 1,200 Vdc(3)(4)
(1) When the insulation monitor is linked to a non-insulated inverter, it is necessary to take into account the DC voltage
limit rather than the AC limit.
(2) IM400 directly connected to the power system.
(3) IM400 used with IM400-1700 or PHT1000 subassemblies.
(4) 1000 Vdc with IM400-1700 and 1200 Vdc with PHT1000.

Electrical Characteristics

Characteristic Values
Range for insulation resistance readings 10 Ω...10 MΩ
Range for capacitance readings 0.01...500 µF
(2,000 µF for PV applications)
Insulation fault signaling Number of thresholds 2 (protected password)
Threshold settings Insulation alarm 0.04...500 kΩ
Preventive 1 kΩ...1 MΩ
insulation alarm
Hysteresis ont the thresholds of insulation alarm and preventive insulation  Setting threshold when the insulation
alarm alarm triggers
 Setting threshold +20% when the
insulation alarm releases
Time delay for signaling 0...7,200 s
Dielectric strength 4000 Vac / 5500 Vdc
7.3 kV impulse
Auxiliary supply voltage 50/60/400 Hz 100...440 Vac
DC 100...440 Vdc
Auxiliary supply voltage tolerances +/-15 %
Monitored system voltage IM400 directly connected +5%
tolerances
IM400 used with IM400-1700 +15%
Maximum device consumption 25 VA / 10 Ω
Measurement voltage Variable 15 Vp, 33 Vp, 120 Vp
Measurement current Variable 375 µAp, 825 µAp, 3 mAp
Fault locating current 3.75 mAp
Extraneous DC voltage Ufg 506 V
Device operating test Self-test / manual test
Internal impedance At 50/60/400 Hz 40 kΩ
Internal resistance Ri of the measuring circuit 40 kΩ

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Vigilohm IM400 - Specifications

Characteristic Values
Output contact Quantity 2 (standard and failsafe)
Type of contact SPDT one changeover contact
Operating principle N/O N/C operation
Electrical endurance 30,000 cycles
Breaking capacity 250 Vac 3A
48 Vdc 1 A, 10 mA minimum load
Minimum switching load 24 Vac/dc 2 mA
Injection inhibition (voltage supplied by IM400) Voltage 24 Vdc
Current 5 mA
Installation category 300 V/OVC III, degree of pollution 2
600 V/OVC II, degree of pollution 2

Electrical Characteristics of IM400-1700 Voltage Adaptor

Characteristic Value
Dielectric strength 15.4 kV impulse
Measurement current Variable 30 µAp, 60 µAp, 220 µAp
Extraneous DC voltage Ufg 1,150 Vdc
Internal impedance At 50/60/400 Hz 430 kΩ
Internal resistance Ri of the measuring circuit 430 kΩ

Mechanical Characteristics

Characteristic Value
Weight 0.75 kg
Thermoplastic case Mounting Flush mount or on grid
Degree of protection Front IP54
Back IP20

Other Characteristics

Characteristic Value
Temperature range For operation –25...+55 °C (65 °C)(1)
For storage –40...+70 °C

Climatic conditions (2) IEC 60068

Use Indoors
Altitude Up to 3000 m
Degree of pollution 2
Overvoltage category 300 V / OVCIII, 600 V / OVCII
Standards Product IEC 61557-8
Safety IEC 61010-1, UL 508, C22.2 no. 14-05
Installation IEC 60364-4-41
Output contact IEC 61810-2
(1) With IM400-1700 voltage adaptor and 230 V ±15 % auxiliary supply.
(2) Suitable for use in all climates:
 Damp heat, equipment not operating (IEC 60068-2-30)
 Damp heat, equipment operating (IEC 60068-2-56)
 Salt mist (IEC 60068-2-52)

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 Vigilohm IM400
Glossary
DOCA0049EN-02 09/2015

Glossary

I
Insulation Alarm
The insulation alarm is triggered when the insulation level on the monitored network goes below the
configured threshold.

P
Preventive Insulation Alarm
The preventive insulation alarm is triggered when the insulation level on the monitored network goes below
the configured threshold – this value cannot be set lower than the Insulation Alarm threshold.

T
Transient Fault
The transient fault appears when the insulation alarm triggers and the insulation level on the monitored
network has gone back above the configured threshold without user acknowledging the insulation alarm.

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DOCA0049EN-02

Schneider Electric Industries SAS As standards, specifications and designs change from time to time, please ask for confirmation
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www.schneider-electric.com 09/2015