Ametek Thermox WDG Insitu User Manual page 41

transient and RFI interference
This section describes transient and RFI interference precautions:
•
Although there are transient and noise protectors on all control unit I/O con-
nections (communications, current outputs, sensor, etc.), this protection is
intended to act as a last line of defense against unwanted transient and RFI
interference.
•
Proper installation practices to prevent the introduction of transients and
noise into the system must be followed. Inductive loads connected to the
control unit must have transient suppressors installed at the inductive loads.
Be sure to place the transient suppressor as close to the load as possible.
Examples of transient suppressors include MOVs, TRANSORBs, and RC
snubbers.
•
AC mains supply wiring should not be run in the same conduit with mains
supply wiring that feeds heavy inductive loads.
•
Avoid running signal wiring in the same cable or conduit with wires that
power inductive loads unless all the cables within the conduit are shielded,
the inductive loads are small, and transient suppressors are used at the loads.
•
Do not run signal lines in the same cable or conduit with high voltage lines.
•
For optimum noise protection, control unit mains supply wiring should be
connected to a circuit separate from any circuit that could introduce tran-
sients into the system. As an example, do not run motors, blowers, or air
conditioners using the same mains supply circuit or conduit as the control
unit's mains supply circuit or conduit.
Installation and Start-Up | 3-17