DC (10-60V) Output Module

Cat. No. 1771OBD Series B

Installation Instructions

To the Installer This document provides information on:

important pre-installation considerations
power supply requirements
initial handling
installing the module
using the indicators for troubleshooting
replacing the fuse
module specifications

Preinstallation Considerations The 1771-OBD Series B module is compatible with all chassis except
1771-A1, 1771-A2, 1771-A4 chassis. Make sure no other output module or
single slot block transfer module is placed in the same module group when
using 2-slot addressing.
The 1771-OBD Series B module has 12 amp output capability. If you want
to use this option, follow the procedures on page 5.

Power Requirements Your module receives its power through the 1771 I/O chassis backplane
from the chassis power supply. The module requires 130mA from the
output of this supply. To calculate the requirements for the backplane
power supply, add 130mA to the power requirements of all other modules
in the I/O chassis. Calculating the requirements will prevent an overload to
the chassis backplane and/or backplane power supply.
Installation Instructions
DC (10-60V) Output Module
Cat. No. 1771-OBD Series B

Initial Handling The dc output module is shipped in static-shielded packaging to guard

against electrostatic discharge damage. Observe the following precautions
when handling the module.

Electrostatic Discharge Damage

ATTENTION: Under some conditions, electrostatic discharge

can degrade performance or damage the module. Observe the
following precautions to guard against electrostatic damage.

Wear an approved wrist strap grounding device, or touch a grounded

object to discharge yourself before handling the module.
Do not touch the backplane connector or connector pins.
If you configure or replace internal components, do not touch other
circuit components inside the module. If available, use a static-free
work station.
When not in use, keep the module in its original static-shielded packaging.

Installing Your Module In this section we tell you how to key your I/O chassis, install your module
and connect your wiring.

Keying Your I/O Chassis

Use the plastic keying bands, shipped with each I/O chassis, to key the I/O
slots to accept only this type of module.
The module circuit board is slotted in two places on the rear edge. The
position of the keying bands on the backplane connector must correspond
to these slots to allow insertion of the module. You can key any connector
in an I/O chassis to receive this module except for the left-most connector
reserved for adapter or processor modules. Place keying bands between the
following numbers labeled on the upper backplane connector:
Between 10 and 12
Between 22 and 24

You can change the position of these keys if system redesign and rewiring
makes insertion of a different module necessary.

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 Installation Instructions
DC (10-60V) Output Module
Cat. No. 1771-OBD Series B

Installing the Output Module

To install the dc output module in your 1771 I/O chassis, follow the steps
listed below.

ATTENTION: Remove power from the 1771 I/O chassis

backplane and wiring arm before removing or installing an I/O
module.
Failure to remove power from the backplane or wiring arm could
cause module damage, degradation of performance, or injury.
Failure to remove power from the backplane could cause injury or
equipment damage due to possible unexpected operation.

1. Turn off power to the I/O chassis.

2. Place the module in the plastic tracks on the top and bottom of the
slot that guides the module into position.
3. Do not force the module into its backplane connector. Apply firm,
even pressure on the module to seat it properly.
4. Snap the chassis latch over the top of the module to secure its position.
5. Connect the wiring arm to the module.
6. Make wiring connections to the field wiring arm as indicated under
‘‘Connecting Wiring to the Output Module.”

Connecting Wiring to the Output Module

Connections to the output module are made to the 21 terminal field wiring
arm (cat. no. 1771-WH) shipped with the module.

ATTENTION: Permanent damage to the module may occur in

applications where frequent overload or short circuit conditions
are possible. To prevent module damage where these conditions
exist, use the optional 1771-WHF or 1771-WHFB fused field
wiring arm instead of the 1771-WH field wiring arm shipped
with the module.

Attach the wiring arm to the pivot bar on the bottom of the I/O chassis.
The wiring arm pivots upward and connects with the module so you can
install or remove the module without disconnecting the wires.
Optional fused wiring arms (cat. no. 1771-WHF or 1771-WHFB) include
individual 3A and 1.5A fuses for each of the 16 outputs. These fuses protect the
module output transistors. For more information on fused wiring arms, refer to
publication 1771-2.116.

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Installation Instructions
DC (10-60V) Output Module
Cat. No. 1771-OBD Series B

Figure 1
Connection Diagram

(See applicable codes and laws.)

+dc A
+dc B
+dc C
+dc D
Output 00 00
Output 01 01
Output 02 02
Output 03 03
Output 04 04
Output 05 05
Output 06 06
Output 07 07 + +
Output 10 10
dc User The output device is sinking
Output 11 11 Output dc
Output 12 12 Device Supply current from the module.
Output 13 13 - -
Output 14 14
Output 15 15
Output 16 16
Output 17 17
-dc E
Sourcing Configuration

(Actual wiring runs in this direction.) 11915I

You must supply dc at terminals A through D on the wiring arm. You need
four dc connections to accommodate the total required surge rating on the
module without overstressing any single connection on the field wiring
arm. Jumper all dc connections together to prevent module damage.
Connect terminal E to dc common.

ATTENTION: Observe proper polarity, as indicated in the

connection diagram (Figure 1) with dc power connections. Reverse
polarity, or application of ac voltage, could damage the module.

Important: You can use a DC (10–60V) Output Module (cat. no.

1771-OBD Series B) to directly drive terminals on the following modules:
DC (5–30V) Input module (cat. no. 1771-IQ)
DC (10–30V) Input module (cat. nos. 1771-IBD, -IBN)
DC (20–60V) Input module (cat. no. 1771-ICD)
DC (12–24V) Input module (cat. no. 1771-IB)
DC (24V) Input module (cat. no. 1771-IQ16)
DC (48V) Input module (cat. no. 1771-IC)

Refer to Figure 2 for direct connection to a 1771-ICD input module.

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 Installation Instructions
DC (10-60V) Output Module
Cat. No. 1771-OBD Series B

Important: Use the same dc supply to power both modules to make sure
that ground is at the same potential.
Figure 2
Driving an Input Module with an Output Module

DC (10-60V) DC (20-60V)
Output Module Input Module
(Cat. No. 1771OBD) (Cat. No. 1771ICD)

20-60V dc
+dc Not used
+dc Not used
+dc Not used
+dc Not used
Output 00 Input 00
Output 01 Input 01
Output 02 Input 02
Output 03 Input 03
Output 04 Input 04
Output 05 Input 05
Output 06 Input 06
Output 07 Input 07
Output 10 Input 10
Output 11 Input 11
Output 12 Input 12
Output 13 Input 13
Output 14 Input 14
Output 15 Input 15
Output 16 Input 16
Output 17 Input 17
-dc dc Common

(Actual wiring runs in this direction) (See Applicable Codes and Laws) 11916I

Your module can drive a total of 12 amps per module. To use this
capability, do the following:

1. Provide external fusing which places a 3 amp fuse in series with each
output channel. Do this by using the 1771-WHF fused wiring arm or
a fused terminal block solution.

2. Replace your module’s existing 10 amp, 250 volt rectifier fuse with a
Littlefuse 15 amp, 250 volt fast blow fuse, part number 314015.

ATTENTION: To configure your module for the 12 amp option,

you must use it in an application providing individually fused
outputs according to the above procedures. The 15 amp fuse will
limit total module current but it will not protect the
output transistors.

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Installation Instructions
DC (10-60V) Output Module
Cat. No. 1771-OBD Series B

Interpreting the Status The front panel of your module contains one green module active
Indicators indicator, 16 red status indicators and one red fuse blown indicator
(Figure 3). The green module active indicator lights when the module is
powered and the processor keyswitch is on ‘‘run”. The indicator light turns
off when the processor resets the outputs.
The module active indicator must be on to properly interpret the red status
indicators. The red status indicators are provided for indication of
individual outputs. They indicate the state to which the transistor is
commanded by the processor and are powered by circuitry within the
module. The indicators will turn on and off as commanded by the
processor. They do not indicate the presence or absence of dc power at an
output terminal.
The fuse blown indicator turns on when the fuse is blown. When the fuse
blown indicator is lit, check the fuse. After checking the fuse, make sure
the field wiring arm is firmly in place. Do this before checking the status of
the other indicators.

Figure 3
Status Indicators

Module Active Indicator (green)

ACTIVE
00 10
01 11
02 12
03 13
04 14 00 to 17 Status Indicators (red)
05 15
06 16
07 17
FUSE
Fuse Blown Indicator (red)
11917I

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 Installation Instructions
DC (10-60V) Output Module
Cat. No. 1771-OBD Series B

Replacing the Fuse An overload or short will cause the single onboard fuse to blow when the module
output exceeds 10A. The onboard fuse may not always protect individual
output transistors. To replace the onboard fuse, do the following:
1. Turn off all power to the I/O chassis and all output device power to
the field wiring arm.

ATTENTION: Remove power from the 1771 I/O chassis backplane

and wiring arm before removing or installing the module.
Failure to remove power from the backplane or field wiring arm
could cause module damage, degradation of performance, or injury.
Failure to remove power from the backplane could cause injury
or equipment damage due to possible unexpected operation.

2. Remove the module from the chassis and replace the blown fuse with
a 10A, 250V rectifier fuse (1/4 x 1-1/4 inch), Littelfuse part number
322010. The fuse is accessible through the side of the module.

ATTENTION: Failure to use the specified replacement fuse

may cause module damage, degradation of performance,
or injury.

3. Replace the module in the chassis and attach the field wiring arm.
4. Turn system power ON.

Troubleshooting Use this table to help you interpret the 1771-OBD status indicators and to
troubleshoot module and system faults.

Indicator Status Description of Fault or System Status Action to Take

Module active ON (green) Normal Indication. None.

Module active ON (green) and Check voltage at output point on swing arm. If voltage is present, take no action. If no
Output status ON (red) voltage is present, replace module.

Module active ON (green) and Output point not ON in data table. None.
Output status OFF (red)

Module failure. Replace module.

Module active OFF and 1. Processor is in program mode. 1. None.

Output status ON (red) or OFF 2. Module not functioning properly. 2. Check chassis power supply and
processor. If they are OK, replace module.

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 Installation Instructions
DC (10-60V) Output Module
Cat. No. 1771-OBD Series B

Specifications Outputs per Module 16

Module Location All locations except 1771A1, A2, and A4 I/O chassis
Output Voltage Range 10 to 60V dc
Minimum Load Current 2.5mA per output
Output Current Rating 2A per output  not to exceed 8A per module
(except when using 12A option)
Surge Current (maximum) 4A per output for 10ms, repeatable every 2 seconds
25A per module for 10ms, repeatable every 2 seconds
On State Voltage Drop (max.) 0.3V dc at rated current
Off State Leakage Current (max.) 0.5mA per output
Signal Delay 0.1ms on or .2ms off
Power Dissipation 5.6 Watts (max.), 1 Watt (min.)
Thermal Dissipation 19.1 BTU/hr (max.), 3.4 BTU/hr (min.)
Backplane Current 130mA @ 5V dc +5%
Optoelectrical Isolation 1500V ac (rms)
Power Rating 0.6 Watt per output
Environmental Conditions
Operational Temperature 0o to 60oC (32o to 140oF)
Storage Temperature -40o to 85oC (-40o to 185oF)
Relative Humidity 5 to 95% (without condensation)
Conductors Wire Size 14 gauge stranded maximum
3/64 inch insulation maximum
Category 11
Keying Between 10 and 12
Between 22 and 24
Fuse 10A, 250V rectifier fuse (1/4 x 1-1/4 inch)
Field Wiring Arm Standard Catalog Number 1771WH
Optional Fused Catalog Number 1771WHF, WHFB
1 Refer to publication 17704.1, Programmable Controller Wiring and Grounding Guidelines.

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Publication 17712.76 - August 1994 PN 95511910
Supersedes Publication 17712.76 - June 1993 Copyright 1994 AllenBradley Company, Inc. Printed in USA