Recommended Wiring Practices - Honeywell VPR100 User Manual

Appendix B
B.4 Recommended Wiring Practices
General rules
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All wiring must conform to local codes and practices.
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Wires carrying similar types of signals (Table Appendix B-1) may be bundled together, but bundles
with different types of signals must be kept separate to prevent inductive or capacitive coupling.
CE compliance
Shielded wires are required on all Analog I/O, low-level Discrete I/O and Communications connections to
meet CE compliance for emissions and immunity. Shields must be connected to the Local Earth Ground
such as the ground bus bar or a grounded panel.
General Wiring Recommendations
All input signal wires, including thermocouples and extension lead wire, must be shielded, and the shields
connected to Earth Ground. DO NOT connect shield to any other unit ground; this will not provide
adequate immunity protection.
Noise Grounding
The shields for all cables must be connected to Earth Ground. DO NOT connect shield to any other unit
ground; this will not provide adequate immunity protection.
Communications Wiring and Grounding
All communication wires must have a triple shield (a shield around each pair for TX and RX and an isolated
overall shield). The shields for each twisted pair are to be tied together and connected to COM on the
communication terminal block. The outer shield must be connected to Earth Ground. DO NOT connect
shield to any other unit ground; this will not provide adequate immunity protection.
Wire bundling
Table Appendix B-1 shows what wiring should be bundled together to prevent inductive or capacitive
coupling.
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