One very rare but common problem is a grounding problem and potential balancing....
.it could be a noise in analog signals due to lack of shield connection to a ground or high voltage induction creating shocks to persons comming in contact with it............!!!!!
One thing that is annoying is a failure of comports (either PLC or Laptop) due to sparking...mainly due to lack of common ground.........
One way we can avoid is connecting PLC and Laptop on common ground .............
what to do when laptop is floating......i.e. when power code is not connected .......
then how we can common the ground between the two....
or is it actually needed in that case............???
come up with your suggestions and help others to understand this topic...........
Regards.,,,,,,,