Minimizing Electrical Noise

The reliability of a control system can be reduced when it is subjected to unusually high amounts of electrical noise, but proper power and grounding can minimize the effects.

Various components of a system can be affected to different degrees. The following observations have been made during system troubleshooting:

Properly installed, standard, non-communicating (called traditional or classic) I/O products that use 4-20 mA analog signals only are typically not affected by electrical noise, except high frequency noise.

High frequency electromagnetic noise generated by ac drives, insulated gate bipolar transistor (IGBT) power switching devices, and other sources can affect all control products without bias to a particular vendor.

Digital data signals used in bus communication systems are susceptible to electrical noise.

These effects can be minimized by:

- Using isolated ac power sources

- Grounding at single points

- Minimizing undue influence on signal wiring from stray magnetic fields

- Selecting appropriate cables and pathways, including adequate cable separation