S7999B SYSTEM DISPLAY
65-0283—2
8
Fig. 5. Switchable S7999B wiring diagram with UDC Controller.
Manual assignment of the UDC controllers to their associated
burner/boiler system is required to allow UDC controllers on
the S7810 Modbus™ network. No automatic assignment is
possible.
Careful Modbus™ addressing is required when inserting UDC
controllers in this configuration since duplicate addresses
aren't allowed. Default Modbus™ addresses for the UDC
controllers may need to be changed for them to work properly
in the network.
M24234
120 VAC
L1
L2
120 VAC (L1)
N
L
NEUTRAL (L2)
EARTH GROUND
V+
12 DC OUT+
V
DC OUT-
(COMMON/GND)
V ADJ
MEAN WELL S-25-12
POWER SUPPLY
CONTROLINKS
CONTROLLER
R7999
C B A
1 2 3 4 5 6 7 8 9
GND
(C)
+12 +12 (b) (a) N/C N/C (a) (b)
S7999B
SYSTEM DISPLAY
3
1
S7810M
MODBUS
MODULE
B
A
C
8
7
6
2
4
UP TO A TOTAL OF 99 S7810M AND UDC CONTROLLERS CAN BE
CONNECTED TO THE S7999B. SEE 65-0249 AND UDC MANUALS
FOR WIRING.
4
1
COM1
COM2
CONNECT ALL THREE “C” WIRES TO V- TERMINAL
ON POWER SUPPLY.
3
CONNECT SHIELD TO EARTH GROUND.
1
UDC
CONTROLLER
D-
D+
SHLD
16
17
18
2 SEE 65-0249 FOR CONTROL BUS (LOCAL RS-485
COMMUNICATION BUS) WIRING.
MODBUS BAUD RATE MUST BE SET FOR 19200.
5
5
120
Ω,
1/4 WATT RESISTOR BETWEEN TERMINALS
A AND B OF THE MODBUS AT THE FARTHEST S7810M
OR UDC MAY BE NECESSARY FOR LONG RS-485 RUNS.
7
7
SEE 65-0238 FOR R7999 WIRING.
6
6
