Detcon 140 - Manual (Page 12)

140 Operators Manual
Model 140 Operator Manual Rev. 1.8 Page 8 of 29
4.2.5
Serial Polling of the Model 140 Controller
When polling this device serially, connect the incoming RS-485 wiring to the terminals labeled “RS-485
IN” (J10) on the Motherboard. For connection to the next polled device in the serial loop, connect the RS-
485 wiring to J25 labeled “RS-485 OUT”. These terminals are labeled “A”, “B”, and “S” (Shield) for
standard RS-485 Modbus™ communication as shown in Figure 4. A jumper on the Motherboard PCB
(JP1) provides the option to leave the shield open or tied to earth ground. Choose the appropriate selection
for the application.
NOTE: The RS-485 wiring should be a 2 conductor, shielded twisted pair (Belden P/N 9841 is
recommended).
4.2.6
Relay Outputs
The standard Model 140 Controller provides four relays. Each relay has 2 Form C contacts. They can be
used to fire annunciating devices or as signal inputs to other control devices. Connect to the relay contact
terminals of the Motherboard PCB. There are two sets of terminals labeled FAULT, ALARM 1, ALARM
2, and ALARM 3. (Figure 4 – J17-J24.) The relays are double pole double throw (DPDT), which allow
more flexibility in the creation of alarm system set-ups. Connections are labeled C (common), NO
(normally open) and NC (normally closed).
NOTE: The current ratings of the relay contacts should not be exceeded. (5A @ 30VDC, 5A @ 250VAC)