Oldham OLCT 80 User Manual page 65

OLCT 80 in RS485 network topology (Modbus)
Figure 42: wiring in RS485 network topology (Modbus).
Item Description
A. 24 VDC power supply. RS485 line.
B. Auxiliary input #1, 4-20 mA, 24 VDC.
C. Auxiliary input #2, 4-20 mA, 24 VDC.
Fault relay output. Dry contact. Interrupting capacity: 30 VDC - 250 VAC – 2A.
D.
Alarm #2 relay output. Dry contact. Interrupting capacity: 30 VDC - 250 VAC – 2A.
E.
Alarm #1 relay output. Dry contact. Interrupting capacity: 30 VDC - 250 VAC – 2A.
F.
120 Ω end-of-line resistor. (To be connected if the sensor is the last in the line.)
G.
H. RS485 line output to subsequent sensor. Parallel terminal on A2.
J. 24 VDC power output to the next sensor in series. Parallel terminal at A1.
Recommended cable type:
Shielded cable designed for RS485 communication, e.g., Belden 3841 cable.
Grounding the housing
Connect the housing's earth terminal to the ground in accordance with
regulation. The OLCT 80 has a dedicated terminal for grounding located on the
outside of the housing (Figure 2, 3).
Closing the cover
The cover must be tightly closed before connecting the cable to the terminal of
the central system. Insert and tighten the locking screw (Figure 2, 4).
4 – Installation
59