Some posts in this thread has a certain flavor of "Is it really needed". - it is.
To make industrial equipment (or any equipment that is to function in an electrically noisy environment) you need - if you want to make reliable equipment - to follow ALL the rules re. noise protection (those in the FAQ and a few more).
You can make a unit without taking all the precautions and install it in plant A and see it working beautifully, then when you install in plant C the house of card collapses.
Pathipati, you can start adding remedies one by one till your unit works at your current installation, but that is absolutely no guarantee that it will work at the next place.


Erik