RKI Instruments M2A - Manual (Page 71)

M2A Transmitter Operator’s Manual 66
Appendix B: PLC and DCS Device Wiring
The M2A can be wired to a PLC or DCS device if desired.
1. Guide multi conductor shielded cable or cables or wires in conduit through the top conduit hub
of the junction box. The number of cables or wires needed will depend on whether any relays
are used and whether the Modbus output is used. Use the following recommendations to
determine how to wire the M2A:
• If Modbus connections will not be used and only the PWR/SIG terminal strip connections
will be used, use four conductor shielded cable or four wires in conduit for connections to
the power/signal terminal strip.
• If the PWR/SIG terminal strip connections and one or more relays are used, route the
connections to the M2A in conduit. Use shielded cable in the conduit for the PWR/SIG
connections and unshielded cable or individual wires for the relay connections. Make sure
any wire or cable used for relay wiring is appropriately rated for the power that it will
carry.
NOTE: If shielded cable is used for the PWR/SIG connections, leave the cable shield’s drain
wire insulated and disconnected at the M2A. You will connect the opposite end of the
cable’s drain wire at the controller or device.
• If the M2A will be wired into a Modbus network, see “Chapter 8: RS-485 Modbus
Output” on page 51.
Table 17: Wire Size for PWR/SIG Connections
Max Distance to Controller
w/18 Gauge Wire
Max Distance to Controller w/
16 Gauge Wire
Max Distance to Controller
w/14 Gauge Wire
2,500 ft. 5,000 ft. 8,000 ft.