S7810M MODBUS™ MODULE
3
65-0249—4
Fig. 3. Wiring S7810M ModBus™ Module.
Wiring (Fig. 3)
1.
Refer to Fig. 3 for proper wiring.
2.
All wiring must comply with all applicable electrical codes,
ordinances and regulations.
3.
Recommended wiring size and type:
a. For all communications, use 22 AWG, 3-wire shielded
cable (Belden part number 8723 or equivalent).
b. For 13 Vdc and remote reset switch operation,
use 22 AWG wire insulated for voltages and temperatures
in the application. Suggested wire types included
TW (60°C), THW (75°C) and THHN (90°C). Terminal
identification numbers and letters are shown in Table 1.
4.
Wire routing:
a. Do not route the communication cable in conduit with
line voltage circuits.
b. Do not route the communication cable close to the
ignition transformers.
c. Route the communication cable outside of conduit if
properly supported and protected from damage.
d. Route the communication cable so that all devices are
connected in a daisy chain configuration.
See Fig. 3.
5.
Maximum wire lengths:
a. Communications bus, 4000 feet (1219 meters).
b. Remote reset switch, 1000 feet (305 meters).
RS485
BUS
A
B
C
M17616B
MULTI-DROP RS-485 COMMUNICATION BUS. UP TO 31 S7810M MODBUS™ MODULES CAN BE CONNECTED TO A SINGLE BUS WITHOUT AN
RS-485 REPEATER. UP TO 99 S7810M MODBUS™ MODULES (SUBNETWORKS) CAN BE CONNECTED TO A BUS WITH RS-485 REPEATERS. WHEN
USING AN RS-485 REPEATER, THE REPEATER MUST BE INSTALLED EVERY 30TH MODULE.
THE SUBNETWORKS MUST BE WIRED IN A DAISY CHAIN CONFIGURATION. RECOMMEND THAT THE PC/PLC BE AT ONE END OF THE DAISY CHAIN.
MODBUS™ COMMUNICATION BUS TERMINATION RESISTORS:
1
2
3
4
5
6
6
6
2
5
5
5
5
5
5
3
3
3
3
2
2
1
1
4
4
8 7 6 5 4 3 2 1
S7810M MODBUS™
MODULE
S7810M MODBUS™
MODULE
S7810M MODBUS™
MODULE
7800 SERIES
RELAY MODULE
8 7 6 5 4 3 2 1
7800 SERIES
RELAY MODULE
8 7 6 5 4 3 2 1
7800 SERIES
RELAY MODULE
INPUT
OUTPUT
+ –
GND
+ –
GND
1 2 3 4 5
A B C
MOMENTARY
PUSHBUTTON
SWITCH
S7800 REMOTE
KEYBOARD
DISPLAY
MODULE
S7830
EXPANDED
ANNUNCIATOR
A B C
R7999
CONTROLINKS™
CONTROLLER
RS-485
REPEATER
A. WITHOUT RS-485 REPEATER:
LOCAL RS-485 COMMUNICATION BUS. THE DEVICES ON THIS BUS MUST BE WIRED IN A DAISY CHAIN CONFIGURATION. THE ORDER OF
INTERCONNECTION IS NOT IMPORTANT. THE MODULES ON THE CLOSEST AND FARTHEST ENDS OF THE DAISY CHAIN REQUIRE A
120 OHM 1/4 WATT TERMINATION RESISTOR BETWEEN TERMINALS 1 AND 2 OR A AND B.
RECOMMEND THREE-WIRE SHIELDED CABLE (BELDEN 8723 SHIELDED OR EQUIVALENT). CABLE SHIELD MUST TERMINATE TO EARTH
GROUND AT BOTH ENDS OF CABLE.
THE MODBUS™ BUS COMMON, S7810M MODBUS™ TERMINAL 6, AND THE LOCAL BUS COMMON (S7810M MODBUS™ TERMINAL 3) MUST NOT
BE ELECTRICALLY CONNECTED TOGETHER.
MODULES AT THE CLOSEST AND FARTHEST END OF THE DAISY CHAIN REQUIRE TERMINATION
RESISTORS. INSTALL A 120 OHM, 1/4 WATT RESISTOR BETWEEN TERMINALS A AND B OF THE PC/PLC. (IF INSTALLED AT ONE END
OF DAISY CHAIN). INSTALL A 120 OHM, 1/4 WATT RESISTOR BETWEEN TERMINALS A AND B OF THE PC/PLC (IF INSTALLED AT ONE END OF
THE DAISY CHAIN. INSTALL A 120 OHM, 1/4 WATT RESISTOR BETWEEN TERMINALS 7 AND 8 OF THE LAST S7810M MODBUS™ MODULE
IN THE DAISY CHAIN.
WHEN AN RS-485 REPEATER IS USED, TWO DAISY CHAIN CONFIGURATIONS ARE EFFECTIVELY FORMED.
MODULES AT THE CLOSEST AND FARTHEST END OF EACH DAISY CHAIN REQUIRE TERMINATION RESISTORS. INSTALL A 120 OHM, 1/4 WATT
RESISTOR BETWEEN TERMINALS A AND B OF THE PC/PLC. (IF INSTALLED AT ONE END OF DAISY CHAIN). INSTALL A 120 OHM,
1/4 WATT RESISTOR BETWEEN INPUT TERMINALS DATA+ AND DATA- OF THE RS-485 REPEATER. INSTALL A 120 OHM, 1/4 WATT RESISTOR
BETWEEN TERMINALS 7 AND 8 OF THE LAST S7810M MODBUS™ MODULE IN THE ADDITIONAL DAISY CHAINS.
B. WITH RS-485 REPEATER:
PC/PLC
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TERMINAL NUMBERS ARE ON 203541 5-WIRE CONNECTOR (SUPPLIED WITH REMOTE MOUNTING BRACKET).
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