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QS7800B NETWORK INTERFACE CONTROLBUS™ MODULE FOR MULTI-DROPPING 7800 SERIES RELAY MODULES
5 65-0227—2
Fig. 6. Multi-drop wiring.
NETWORK INTERFACE UNIT
PLUG-IN PLUG-IN
POWER
SUPPLY
L1
L2
GND
SYSTEM 2
A
B
C
M11347A
UNIVERSAL
POWER
SUPPLY
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. Q7700A1014, 120V, 50/60 HZ; Q7700B1004,
UNIVERSAL POWER SUPPLY, 100 TO 250V, 50/60 HZ.
CONNECT PIGTAIL LEADWIRES (Q7700A ONLY):
BLACK—L1
WHITE—L2
GREEN—GROUND
MULTI-DROP RS-485 COMMUNICATION BUS. UP TO 31 S7810B MULTI-DROP SWITCH MODULES (SUBNETWORKS) CAN BE CONNECTED TO A SINGLE
QS7800B CONTROLBUS™ MODULE WITHOUT AN RS-485 REPEATER. UP TO 61 S7810B MULTI-DROP SWITCH MODULES (SUBNETWORKS) CAN BE
CONNECTED TO A SINGLE QS7800B CONTROLBUS™ MODULE WITH AN RS-485 REPEATER.
INSTALL THE REPEATER BETWEEN THE 30TH AND 31ST SUBNETWORKS.
UP TO SIX QS7800B CONTROLBUS™ MODULES CAN BE INTERFACED WITH THE NETWORK INTERFACE UNIT. MAXIMUM OF 222 MULTI-DROP
SUBNETWORKS CAN BE INTERFACED WITH A SINGLE Q7700 NETWORK INTERFACE UNIT.
LOCAL SYSTEM (SUBNETWORK). REFER TO S7810B MULTI-DROP SWITCH MODULE INSTRUCTIONS, FORM 65-0228, FOR WIRING INSTRUCTIONS.
THE SUBNETWORKS MUST BE WIRED IN A DAISY CHAIN CONFIGURATION. IT IS RECOMMENDED THAT THE QS7800B CONTROLBUS™ MODULE
BE AT ONE END OF THE DAISY CHAIN.
22 AWG (OR LARGER) TWISTED PAIR SHIELDED CABLE (BELDEN 8723 OR EQUIVALENT) IS RECOMMENDED. CABLE SHIELD MUST BE GROUNDED
AT EACH END.
MULTI-DROP COMMUNICATION BUS TERMINATION RESISTORS:
A. WITHOUT RS-485 REPEATER: 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 QS7800B CONTROLBUS™ MODULE. INSTALL A 120 OHM, 1/4 WATT, RESISTOR
BETWEEN TERMINALS 7 AND 8 OF THE LAST S7810B MULTI-DROP SWITCH MODULE IN THE DAISY CHAIN.
B. WITH RS-485 REPEATER: 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 QS7800B CONTROLBUS™ MODULE. 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 OUTPUT 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 S7810B MULTI-DROP SWITCH MODULE IN THE SECOND DAISY CHAIN.
FOR Q7700B NETWORK INTERFACE UNIT.
1
2
3
4
5
6
7
8
9
10
1
2
3
5
10
9
9
9
9
8
8
7
7
7
6
6
6
4
8 7 6 5 4 3 2 1
S7810B MULTI-DROP
SWITCH MODULE
7800 SERIES
RELAY MODULE
8 7 6 5 4 3 2 1
S7810B MULTI-DROP
SWITCH MODULE
7800 SERIES
RELAY MODULE
TO LOCAL
SYSTEM
8 7 6 5 4 3 2 1
S7810B MULTI-DROP
SWITCH MODULE
7800 SERIES
RELAY MODULE
TO LOCAL
SYSTEM
TO LOCAL
SYSTEM
INPUT
OUTPUT
+ –
GND
+ –
GND
RS-485
REPEATER