Flowserve StarPac II Control Valves - Manual (Page 58)

StarPac II User Interface Manual 52
4-20 mA Command Input, Auxiliary Input, and Feedback Output
These signals are isolated but shielded twisted pair wire should be used
to reduce crosstalk from other signals. Again, the shield should be
connected only at the source.
Discrete Inputs and Outputs
These signals are isolated, yet because they are frequently used to
switch high voltage (120 VAC), they should be run in separate shielded
wire paths away from the other StarPac signals.
AIB and RS-232 to RS-485 Converter Connection
When connecting a StarPac system to an AIB or RS-232 to RS-485
converter, no shield or ground connections exist, the 24 VDC power
and RS-485 communication shield drain wires must be connected to a
convenient ground near the AIB or converter--no other grounding is
needed.