Isolated 4-20Ma Output 10-0250 Option - Oldham OLCT 200 User Manual

RS-485 Modbus networks should be wired as shown in Figure 2-11. Each OLCT 200
connected represents an RTU and must have a unique RTU address. RTU addresses
are assigned in the Modbus setup menu described in section 4.10. Cabling must be a
"daisy chain" as opposed to a "star" pattern for reliable operation. The "end of line" unit
should have J1 installed in the 'A' position for terminating resistor installation. All
others should have J1 in the 'B' position. Front panel Rx / Tx LEDs are helpful
troubleshooting tools.
Figure 2-11: RS-485 Modbus Wiring

2.8 Isolated 4-20mA Output 10-0250 Option

Description:
The optional 10-0250 Isolated 4-20mA option (Figure 2-12) provides dual 4-20mA
outputs that are electrically isolated from sensor inputs and the 24 VDC power source.
Each 4-20mA output share the same common terminal and are not isolated from each
other. This board is "piggybacked" behind the 10-0232 Display Assembly (Figure 2-3).
Addition of this option requires 4-wire mode 4-20mA operation and thereby requires the
I/O Power Supply board (Figure 2-5).
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