Industrial Electronic Weighing

MC 302 WEIGHT INDICATOR AND BATCHER

INSTRUMENT CONNECTIONS AND

HARDWARE CONFIGURATION MANUAL

Rev. 01 0304
 MC 302 TECHNICAL FEATURES

Power supply 230 Vac 50/60 Hz (115 Vac optional)

Power consumption 15 VA
Insulation Class II
Installation category Cat. II
Operating temperature -10°C - +40°C (max. humidity 85% without condensation)
Storage temperature -20°C - +50°C

Weight display 7 digits red LED’s, 7 segments (14 mm high)

Status LED’s 7 red LED, Æ3 mm
Keyboard Membrane keyboard with 14 keys and buzzer

Overall dimensions 144 x 72 x120 mm (l x h x d) (DIN43700)

Panel cut-out 139 x 67 mm
Case Fireproof Noryl (UL 94 V1)
Front panel protection level IP54
Connections Pull-out terminal blocks pitch 5.08 (power supply pitch 7.5 mm),
serial ports on 9 poles SUB-D connector.

Load cell excitation 5 Vdc / 120 mA (max. 8x350W load cells) short circuit proof
Input sensitivity 0.02 mV min.
Linearity < 0.01% of the full scale
Temperature drift < 0.0003% of the full scale / ºC
A/D converter resolution 24 bit
Displayed weight resolution Up to 600,000 divisions on the total capacity (10,000 divisions in
case of “legal for trade”)
mV/V input signal range From -3.9 to +3.9 mV/V
Weight acquisition frequency 6 Hz - 160 Hz
Digital filter Programmable from 0.2 Hz to 50 Hz
Weight decimal digits 0 to 4 decimal digits
Zero and full scale calibration Data-sheet or Dead-load calibration

Logic outputs 6 relays (NA contact) max 115 Vac/30 Vdc, 0.5 A each
Optional: Up to 2 external 8-relay modules. Features as above
Logic inputs 8 opto-isolated 12 Vdc / 24 Vdc PNP

Serial ports (2) COM1: Rs232c half duplex

COM2: Rs422/Rs485 half duplex.
Maximum cable length 15m (Rs232c) and 1000m (Rs422 and Rs485)
Serial protocols ASCII, Modbus RTU, EPSON or Alfapanel Printers
Baud rate 1200, 2400, 4800, 9600, 19200, 38400, 115000 selectable

Programme code memory 128 Kbytes FLASH resettable on board by RS232

Data memory 8 Kbytes extendable to 36 Kbytes
Optional alibi memory 1 Mbyte (up to 160,000 weighing procedures recorded)
Clock / calendar On mother board with buffer battery

Analog output Voltage: 0 - 10 V / 0 - 5 V Current: 0 - 20 mA / 4 - 20 mA

Resolution 16 bits
Calibration Digital via keyboard
Impedance Voltage: minimum 10KW Current: maximum 300W
Linearity 0.03% of the full scale
Temperature drift 0.001% of the full scale / ºC

Conformity to Standards EN50081-1, EN50082-2, EN61010-1, EN45501

 DECLARATIONS OF CONFORMITY

Pavone Sistemi S.r.l.

Via Dei Chiosi , 18
20040 CAVENAGO BRIANZA (MI)

DECLARES that the product named: MC 302

used as described in the installation and use manual, conforms to the following standards:

ELECTROMAGNETIC COMPATIBILITY:

EN50081-1
EN50082-2

On the basis of that provided for in directive 89/336/CEE and amendments.

ELECTRICAL SAFETY:
EN61010-1

On the basis of that provided for in directives 73/23/CEE and 93/68/CEE and amendments.

The CE mark has been stamped on the rear of the product

Mezzago, 20 - 05 - 2003

___________________________ 03
(The Manager) (last two figures of the year of
application of the mark)

WARNINGS
This manual aims to use texts and figures in order to provide the operator with instructions and information
about the basic criteria for the installation and correct use of the instrument.

· Specialized personnel should only install the instrument, after having read and understood this manual. By
“specialized personnel”, we mean personnel who, due to specific training and professional experience,
have been expressly authorized by the system safety manager to carry out the installation.

· Do not power the instrument with voltage outside the limits specified in the characteristics.

· The user is responsible for ensuring that the installation conforms to relative current regulations.

· In the case of anomalies, contact the nearest Service Centre. Any unauthorized attempt at dismantling or
modifying the instrument will void the warranty and relieve the Manufacturer of all responsibility.

· The appliance has been designed and manufactured for use in weighing and dosage processes. Any
improper use will relieve the Manufacturer of all responsibility.
 SYMBOLS

A list of the symbols used in the manual to attract the reader’s attention follows below:

Warning! Risk of electric shock.

Warning! Specialized personnel must perform this operation.

Read the following instructions carefully.

CONTENTS

SECTION 1 : INSTRUMENT INSTALLATION Page 1.5

WARNINGS Page 1.5

INSTRUMENT ASSEMBLY Page 1.5
INSTRUMENT POWER SUPPLY Page 1.6
LOAD CELL CONNECTION Page 1.7
LOGIC INPUT CONNECTION Page 1.7
LOGIC OUTPUT CONNECTION Page 1.8
RS 232 SERIAL CONNECTION TO PERSONAL COMPUTER Page 1.9
RS 485 SERIAL CONNECTION Page 1.10
RS 422 SERIAL CONNECTION TO REMOTE DISPLAYS Page 1.11
RS 232 SERIAL CONNECTION TO ALFAPANEL PRINTER Page 1.12
ANALOG OUTPUT CONNECTION Page 1.13
ANALOG OUTPUT TYPE MODIFICATION Page 1.13
RS 232 SERIAL CONNECTION TO BCD OUTPUT CARD Page 1.14
SERIAL CONNECTION TO THE EXTERNAL 8-RELAYS MODULE S097 Page 1.15
SERIAL CONNECTION TO 80 COLUMN DOT MATRIX PRINTER Page 1.15
PROFIBUS-DP CONNECTION Page 1.16
PROFIBUS-DP CONNECTOR DESCRIPTION Page 1.17
S125 MODULE TECHNICAL FEATURES Page 1.17
PROFIBUS CABLE INFORMATION Page 1.18
SUMMARY OF CONNECTIONS Page 1.19
HARDWARE PROBLEM TROUBLESHOOTING Page 1.20
 Seection 1 – INSTRUMENT INSTALLATION

SECTION 1: INSTRUMENT INSTALLATION

WARNINGS

· As indicated above, specialized personnel must carry out the following procedures.
· Do not make connections when the instrument is switched on.

INSTRUMENT ASSEMBLY

The instrument is installed as a panel in a cavity with a panel cut-out of 139 x 67 mm and fixed into place with
the 2 turnbuckles provided.

· An isolating switch must be installed near the instrument in order to be able to cut the power
supply at any time.
· Consider that the depth of the instrument, with the pull-out terminal blocks assembled, is 135
mm. and the necessary space must be reserved for the connections.
· Do not install the instrument near power appliances (motors, inverters, contacts, etc.) or appliances that
do not meet CE standards for electromagnetic compatibility.
· The connection wire for the load cells must be no more than 140 m/mm² long.
· The Rs232 serial line must be no more than 15 metres long (EIA RS-232-C standards).
· The warnings indicated in the connection of the individual peripherals must be respected.

INSTRUMENT IDENTIFICATION DATA PLATE

mod. MC
302
Serial No.

It is important to provide this information when requesting information or instructions regarding the
instrument, along with the programme number and the version, which are shown on the manual
cover and are displayed when the instrument is switched on.

REAR PANEL

Supply 230V ~ 50Hz - 15W

230V ~
L N T Fuse 1 2 3 4 5 6 7 8 9 10 11
T 80mA

MA MB

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 COM

MC

In keeping with standards, some instructions are printed on the back of the instrument in order to facilitate the
installation process.

Page 1.5
 Section 1 – INSTRUMENT INSTALLATION

INSTRUMENT POWER SUPPLY

· The instrument is powered through the MA terminal block.

· The power supply wire must be grounded and must be channelled separately from other
supply wires with different voltages, from the load cell wires and the logic input/output wires.

Supply voltage: 230V ~ 50/60 Hz 15W

Fuse: T 80mA with delayed fusion

3 pole MA TERMINAL BLOCK CONNECTION, pitch 7,5 mm

L. LINE
N NEUTRAL
E GROUND

The instrument has class II insulation (double insulation) and is grounded for practical reasons;
therefore check the presence of valid ground protection.

LOAD CELL CONNECTION

· The load cell cable must not be channelled with other cables (i.e. outputs connected to
remote switches or power supply wires), but must follow its own route.
· Any cable extensions must be carefully shielded, respecting the colour codes and using the
same type of wire as that supplied by the manufacturer. The extension connections must be
soldered or connected through support terminal blocks or the joint block supplied separately.
· The load cell wire must not have more conductors than those effectively used (4 or 6). In the case of a 6-
conductor wire, of which only 4 are used (excitation + and -, signal + and -), connect the sense + and -
wires to the respective polarities of the excitation wires.

A maximum of eight 350-ohm load cells can be connected to the instrument in parallel. The load cell
excitation voltage is 5 Vdc and is protected against a temporary short circuit. The instrument’s input signal
range requires the use of load cells with sensitivity from 1 mV/V to 3.9 mV/V.
The load cell wire must be connected to terminals 1 ... 6 of the pull-out 15 pole MC terminal block.

4 WIRE CONNECTION SIGNAL -

1. EXCITATION - EXCITATION +
2. EXCITATION +
3. Short circuit with terminal 2. SIGNAL +
4. Short circuit with terminal 1.
5. SIGNAL -
6. SIGNAL + EXCITATION -

6 WIRE CONNECTION SIGNAL -

EXCITATION +
1. EXCITATION -
2. EXCITATION + SENSE +
3. SENSE + SIGNAL +
4. SENSE -
5. SIGNAL - SENSE -
6. SIGNAL + EXCITATION -

Connect the load cell wire shield to ground (terminal T in the MA terminal block).

Page 1.6
 Seection 1 – INSTRUMENT INSTALLATION

LOGIC INPUT CONNECTION (MC TERMINAL BLOCK)

The logic inputs are electrically isolated from the instrument through opto-isolators.

· The logic input connection wires must not be channelled with power or supply wires.
· Use the shortest possible connection wire.

The inputs are active when a voltage of 24 Vdc is applied (PNP logic).

The instrument is supplied in two possible configurations:

INTERNAL POWER SUPPLY: this is the standard configuration. In order to activate a logic input, it is
necessary to close the relative terminal to the common, consisting of the positive supply pole (terminal 13 in
the MC terminal block).

EXTERNAL POWER SUPPLY: The instrument is only configured in this way if expressly requested by the
client. In order to activate a logic input, it is necessary to apply + 24V to the relative terminal and 0 V to the
common (terminal 13 in the MC terminal block).

The following diagrams show the two types of connection using, for example, a button for inputs 1 and 2 and
a switch for inputs 3, 4, 5 and 6.

INTERNAL POWER SUPPLY EXTERNAL POWER SUPPLY

7 input 1 7 input 1

input 2 input 2
I 8 I 8
N input 3 N input 3
S 9 S 9
T input 4 T input 4
R 10 R 10
U input 5 U input 5
M 11 M 11
E E (pos.) +
12 input 6 12 input 6
N N
T common T common 24 Vdc
13 13
(neg.) -
MC TERMINAL BLOCK (15 POLES) MC TERMINAL BLOCK (15 POLES)

If the inputs have an external power supply, we recommend supplying them with a
stabilized voltage, because a rectified voltage (pulsing) could cause constant input
activation – de-activation.

Page 1.7
 Section 1 – INSTRUMENT INSTALLATION

LOGIC OUTPUT CONNECTION (MB TERMINAL BLOCK)

The logic outputs are electrically isolated from the instrument through opto-isolators.
The logic outputs are provided on a 6 relays with commons grouped on 2 terminals. The rate of each contact
is 0.5A / 24Vdc 115Vac. Each output is enabled when the contact is closed.

· Other machinery in the area may normally subject to strong magnetic fields and electrical
disturbance cause the environment where the instrument is installed; it is therefore best to
make normal provisions in order to prevent these affecting the typical signals of an electronic
precision instrument. (filters on the remote switches, diodes on the 24
Vdc relay, etc.)

The output connection diagram follows below:

MB TERMINAL BLOCK (11 poles)

Relays
Output contact 1
1
Output contact 2
2
Common
3
1
Output contact 3
Instrument 4
Output contact 4
5
Output contact 5
6
Output contact 6
7
Common
8
2

Page 1.8
 Seection 1 – INSTRUMENT INSTALLATION

RS 232 SERIAL CONNECTION TO PERSONAL COMPUTER

· In order to create the serial connection use a shielded cable, making sure that only one of
the two shield ends is grounded. If the cable has more conductors than those used, connect
the free conductors to the shield.
· The serial connection wire must be a maximum of 15 metres long (EIA RS-232-C
standards), in addition to which it is necessary to adopt the Rs422 interface that the instrument can be
equipped with.
· The cable must not be channelled with other cables (i.e. outputs connected to remote switches or power
supply wires), but must follow its own route.
· The PC used for the connection must conform to the EN 60950 standard.

The diagram below illustrates connection of the instrument to a 25 pole PC connector:

9 pole Sub-D connector 25 pole Sub-D connector

signal ground
5 7

3
data TX
3 PC
Instrument
data RX
2 2

The diagram below illustrates connection of the instrument to a 9 pole PC connector:

9 pole Sub-D connector 9 pole Sub-D connector

signal ground
5 5

3
data TX
2 PC
Instrument
data RX
2 3

Page 1.9
 Section 1 – INSTRUMENT INSTALLATION

RS 485 SERIAL CONNECTION (optional)

This type of connection makes it possible to connect several instruments to one MASTER unit (generally a
PC or a PLC), using a single serial line and therefore just one MASTER serial port. A maximum number of 32
units may be connected. Obviously, the master unit must also be equipped with the RS485 serial interface.

· The serial connection cable must be suitable for RS485 serial communications, with two
twisted pairs and relative protective shielding.
· The cable must not be channelled with other cables (i.e. outputs connected to remote
switches or power supply wires), but must follow its own route.
· The PC used for the connection must conform to the EN 60950 standard.

CONNECTION TO RS232/RS485 SERIAL CONVERTER

9 pole Sub-D connector 25 pole Sub-D connector

TXD -
RXD - 15
7
TXD +
RXD + 14
9
RXD -
TXD - 10
Instrument 6
RXD + PC
TXD + 11
4
- 12

Other Instrument
7.5 Vcc + 13

RXD -
7
RXD + RS232/ RS485 SERIAL
9 CONV ERTER

Instrument TXD -
6
TXD +
4

It should be born in mind that the last device connected must be terminated with a suitable
resistance value. Make sure that this instrument is connected in the last place in the chain.

Page 1.10
 Seection 1 – INSTRUMENT INSTALLATION

RS 422 SERIAL CONNECTION TO REMOTE DISPLAYS (optional)

It is possible to make long distance serial connections using the RS422 serial interface.

· The serial connection cable must be suitable for RS422 serial communications, with two
twisted pairs and relative protective shielding.
· In the case of remote display connection, a single twisted pair relative to the transmission
(TX +, TX -) is sufficient.
· The cable must not be channelled with other cables (i.e. outputs connected to remote
switches or power supply wires), but must follow its own route.

RS 422 SERIAL CONNECTION WITH REMOTE DISPLAY MOD. H60

9 pole Sub-D connector -J1- 9 pole Sub-D connector

TXD - RXD -

Instrument
6
TXD + RXD +
1
88888
4 9
7 H60 REMOTE
DISPLAY

RS 422 SERIAL CONNECTION WITH REMOTE DISPLAY MOD. H100

9 pole Sub-D connector 7 pole “Amphenol” connector

TXD - RXD - 6
6 1

Instrument 4
TXD + RXD + 4
7

88888
7
H100 REMOTE
DISPLAY

Page 1.11
 Section 1 – INSTRUMENT INSTALLATION

RS 232 SERIAL CONNECTION TO ALFAPANEL PRINTER (optional)

The ALFAPANEL printer used must be equipped with Rs232 serial interface. Consult the relative manual for
the correct setting of the dipswitches assembled on the printer’s serial interface card.

· The printer must be assembled so that the serial connection wire connecting it to the
instrument is not longer than 15 metres (EIA RS-232-C standards).
· A male, 25 poles D-connector to be inserted into the female connector on the rear printer
panel, must be wired to the connection wire.
· In order to create the serial connection use a shielded cable, making sure that only one of the two shield
ends is grounded. If the cable has more conductors than those used, connect the free conductors to the
shield.
· The cable must not be channelled with other cables (i.e. outputs connected to remote switches or power
supply wires), but must follow its own route.
· The panel cut-out for the Alfapanel printer is 112 x 112 mm.
· Use the dedicated power supply to power the printer.

9 pole Sub-D connector 25 pole Sub-D connector

Signal ground Alfapanel printer

5 7
Data TX
3 3
Data RX
Instrument 2 2
Clear to Send
8 20

In the case of a printer equipped with a 9-pole connector instead of 25 the connections will be
“pin to pin” (5 « 5, 3 « 3, 2 «2, 8 « 8).

Page 1.12
 Seection 1 – INSTRUMENT INSTALLATION

ANALOG OUTPUT CONNECTION (optional)

When having this hardware configuration, the instrument provides an opto-isolated analog current or voltage
output.

Characteristics:

· Voltage Analog output: range from 0 to 10 Volts, minimum load 10KW

· Current Analog output: range from 0 to 20 mA or from 4 to 20 mA. The maximum load is 300W.

The settings for the type of analog output provided (voltage or current) are decided in the factory and must be
specified upon purchase.

· In order to create the connection use a shielded cable, making sure that only one of the two
shield ends is grounded.
· The analog transmission is particularly sensitive to electromagnetic disturbance. We
therefore recommend that the cable is as short as possible and is channelled separately.

CONNECTION ON THE MC TERMINAL BLOCK (15 poles)

14 +

- Analog output
15

ANALOG OUTPUT TYPE MODIFICATION

The analog output is normally set in voltage or current in the factory as requested by the client. It is however
possible to change this setting by moving a jumper bridge present on the instrument base card (S118).

· Warning! Qualified personnel must carry out this operation with express
authorization from the manufacturer.
· Disconnect the appliance from the power supply before carrying out the operation
described below.
· Non-observance of these regulations will void the instrument’s guarantee and relieve
the Manufacturer of all responsibility.

Setting modification procedure:

1) Disconnect the instrument power supply.

2) Remove the back frame and cover by acting on the side tongues.
3) Use a flat screwdriver to act as a lever between the keyboard and the cover until the keyboard comes out.
4) Slide off the flat that connects the keyboard to the display board.
5) Remove the electronic cards from the rear part of the container.
6) Use a 5.5 mm spanner to unscrew the two nuts that hold the power supply card in place (S119)
7) Remove the power supply card.
8) The base card (S118) is now visible.
9) The topography of the base card (S118) is illustrated below.
10) The bridge marked with the letters V and I indicates the type of analog output selected:
 Voltage output: jumper bridge between V and central

Page 1.13
 Section 1 – INSTRUMENT INSTALLATION

 Current output: jumper bridge between I and central

11) Position the jumper bridge as required.

12) Reconnect the wires that were disconnected.
13) Reassemble the device.
14) Place it in the cover.
15) Attach the keyboard to the card and the container.
16) Insert the back frame and cover
17) Reconnect the supply line and anything else to the instrument.
18) Power the instrument and configure the analog option.

JP8:
I = Current output
V = Voltage output

When the analog output is changed from voltage to current or vice versa, disconnect the
digital meter and reconnect it with the right configuration since an output in Volts with a
ammeter in series could damage the circuit (causing the output to short circuit).

RS 232 SERIAL CONNECTION TO BCD OUTPUT CARD

· In order to create the serial connection use a shielded cable, making sure that only one of
the two shield ends is grounded. If the cable has more conductors than those used, connect
the free conductors to the shield.
· The serial connection cable should be no longer than 3 metres. The cable must not be
channelled with other cables, but must follow its own route if possible.
·

9 pole Sub-D connector 9 pole Sub-D connector

Signal ground
5 5 BCD
Data TX BOARD
Instrument 3 2

Page 1.14
 Seection 1 – INSTRUMENT INSTALLATION

SERIAL CONNECTION TO THE EXTERNAL 8 RELAYS MODULE S097 (optional)

This type of connection is only available for instruments equipped with software that provides for the
management of supplementary outputs, such as the batching from 5 to 12 components for example.

· In order to create the serial connection use a shielded wire, making sure that only one of
the two shield ends is grounded. If the cable has more conductors than those used, connect
the free conductors to the shield.
· The serial connection wire should be no longer than 100 metres. The wire must not be
channelled with other wires, but must follow its own route if possible.

MB TERMINAL BLOCK MA TERMINAL BLOCK

COM+
9 3
SCLK S097
10 5 BOARD
Instrument
TXD
11 4

SERIAL CONNECTION TO 80-COLUMN DOT MATRIX PRINTER (optional)

The printer must be equipped with Rs232 serial interface. The printer must be configured in order to receive
the data from the serial interface (instead of the parallel one) and the following specifications must be set:

· Baud rate: 9600 bps (or other selection in keeping with the speed selected on the instrument).
· Data bits: 8 bits
· Start bit: 1 bit. Parity bit: 0 bit. Stop bit: 1 bit.
· Handshaking: DTR protocol.

Refer to the printer manual in order to make the selections.

· In order to create the serial connection use a shielded cable, making sure that only one of
the two shield ends is grounded. If the cable has more conductors than those used,
connect the free conductors to the shield.
· The printer’s serial interface connector is normally a female, 25 pole D-connector,
therefore a male 25 pole D-connector should be wired to the connection cable.
· The serial connection cable should be no more than 15 metres long (EIA RS-232-C
standards). In addition to this measure, it is necessary to adopt the Rs422 serial interface
that the instrument can be optionally equipped with.

9 pole Sub-D connector 25 pole Sub-D connector

Signal ground
5 7
Data TX
3 3
Instrument Printer
Clear to Send
8 20

Page 1.15
 Section 1 – INSTRUMENT INSTALLATION

PROFIBUS-DP CONNECTION (OPTIONAL)

Profibus-DP connection is available as an option on the MC 302 instrument and is developed through the
help of an external module installed in a container for assembly on the DIN guide.
The external Profibus module is identified by the code S125
The instrument is connected to the external Profibus module using the RS422 serial line.

A connection diagram for the two devices and a drawing of the Profibus-DP module are illustrated below:

9 pole Sub-D connector (J4) 9 pole Sub-D connector

Modbus RTU side

TXD - RXD -
7 7
TXD + RXD +
S125 9 9
Module RXD - TXD -
6 6 Instrument
RXD + TXD +
4 4
RESET RESET
8 8
GND GND
1 1

COM1 (RS232), limited to RX, TX and GND signals (without CTS), remains available on the same MC302
instrument 9-pole connector. All the protocols, except MODBUS, can be activated.

MODBUS RTU CONNECTOR

TO MC302 INSTRUMENT
24Vdc

PROFIBUS-DP CONNECTOR
TO FIELDBUS SIDE

Page 1.16
 Seection 1 – INSTRUMENT INSTALLATION

PROFIBUS-DP CONNECTOR DESCRIPTION

Pin Description Function

Housing Shield -
1 Not connected -
2 Not connected -
3 B-Line, Positive RS485 Rxd/TxD Non-inverting RxD/TxD
4 RTS, Request To Send Request to send
5 GND BUS GND from RS485
6 +5V BUS +5 V from RS485
7 Not connected -
8 A-Line, Negative RS485 RxD/TxD Inverting RxD/TxD Profibus Connector on
9 Not connected - S125 module

MODULE S125 TECHNICAL FEATURES

Power supply 24 Vdc +/- 15%

Power consumption 3 VA
Insulation Class II
Installation category Cat. II
Operating temperature -10°C - +40°C (max. humidity 85% without condensation)
Storage temperature -20°C - +50°C

Serial port 1 (9P male) Rs422

Baud rate 34,800 bit/sec.
Maximum cable length 100m
Serial protocol Modbus RTU
Serial port 2 (9P female) PROFIBUS DP
Baud rate Up to 12 Mbit/sec.
Maximum cable length Depends on the PROFIBUS network

Overall dimensions 71 x 90 x 58 mm (l x h x d)
Assembly Support for DIN section or OMEGA bar
Case Fireproof NORYL UL 94 V-0
Front panel protection level IP40
Weight 120 g
Connections 1 x 2 pole pull-out terminal block, pitch 5.08 for the 24 Vdc power
supply. 2 x 9 pole Sub-D connectors for serial ports

Conformity to Standards EN50081-1and EN50082-2 for EMC

EN61010-1 for Electrical Safety

Page 1.17
 Section 1 – INSTRUMENT INSTALLATION

NOTES ON PROFIBUS CABLE

The cable to be used for connecting the instrument in a Profibus network is shielded with twisted pairs.
The typical impedance of the cable used should be between 100 and 130 Ohm (f> 100 kHz).
The capacity of the cable (measured between conductor and conductor) should be below 60 pF/metre.
The minimum section of the conductor should be no less than 0.22 mm²

In a Profibus-DP network it is possible to use both type A and type B cables, depending on the performances
required: The following table sums up the characteristics of the cable to be used:

CHARACTERISTICS TYPE A CABLE TYPE B CABLE

Impedance from 135 to 165 ohm from 100 to 300 ohm
(f = 3 – 20 MHz) (f > 100 kHz)
Capacity < 30 pF/m < 60 pF/m
Resistance < 110 ohm/km -
2
Conductor section > 0.34 mm > 0.22 mm²

The following table shows the maximum length of the line with type A cable and with type B cable depending
of the different communication speeds required:

Baud rate (kbit/s) 9.6 19.2 45.45 93.75 187.5 500 1500 3000 6000 12000
Length cable type A in metres 1200 1200 1200 1200 1000 400 200 100 100 100
Length cable type B in metres 1200 1200 1200 1200 600 200 - - - -

Page 1.18
 Seection 1 – INSTRUMENT INSTALLATION

SUMMARY OF CONNECTIONS

A summary of the connections to be made in terminal blocks MA, MB and MC is illustrated below.

Supply 230V ~ 50Hz - 15W

230V ~
L N T Fuse 1 2 3 4 5 6 7 8 9 10 11
T 80mA
MA MB

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 COM

MC

CONNECTIONS

MC Terminal block COM

NR. MA Terminal block MB Terminal block
15Pole pitch 5.08 D-SUB 9P Connector
3Pole pitch 7.5 11Pole pitch 5.08
1 230V~ line Output 1 Load cell Excitation -
2 230V~ neutral Output 2 Load cell Excitation + (RX) RS232 (COM1)
3 Ground Common Outputs Load cell Sense + (TX) RS232 (COM1)
4 Output 3 Load cell Sense - (TX +) RS422 (COM2)
5 Output 4 Load cell Signal - GND (COM1)
6 Output 5 Load cell Signal + (TX -) RS422 (COM2)
7 Output 6 Input 1 (RX-) RS422 (COM2)
8 Common Outputs Input 2 (CTS) RS232 (COM1)
9 COM+ (*) Input 3 (RX+) RS422 (COM2)
10 SCLK (*) Input 4
11 TXD (*) Input 5
12 Input 6
13 Common Inputs

14 Analog output +
(Input 7)
15 Analog output -
(Input 8)

(*) Used for the connection to the 8 relays external module (see page 1.15)

Page 1.19
 Section 1 – INSTRUMENT INSTALLATION

HARDWARE PROBLEM TROUBLESHOOTING

· Warning! Qualified personnel must carry out the operations described below.
· The fuse should only be replaced when the instrument is cut off from the voltage.

PROBLEM POSSIBLE CAUSE SOLUTION

The instrument does not switch · The fuse has blown · Replace the fuse with an
on identical T 80 mA fuse
· The supply voltage is incorrect
· Provide the correct power
supply voltage

The displayed weight does not · The load cell does not work · Use a digital meter to check
change correctly or is not correctly that there are 5V between Exc
connected + and – and between Sense +
and – . Then check the
millivolt signal change
between signal + and – when
loading or unloading the load
cell.
The instrument displays 0-L on · The load cell gain value is · In the parameter programming
the most part of the scale wrong function, set the correct value
in the weight measurement
field

· In the parameter programming

· The full scale value is wrong function, set the correct
maximum weighing value
The inputs and/or the outputs do · Incorrect wiring or software · Use the I/O Test function to
not work correctly setting check whether the inputs and
outputs are working properly
and check the specific
programme settings.
The instrument does not accept · The number of points available · Repeat the calibration so that
the set calibration is insufficient for the required the number of points
calibration representing the full scale is
less than 600000

If the anomaly is not included amongst the above or the proposed solutions do not solve
the problem, contact an assistance centre.

Page 1.20