I have an issue that appears to be relating to noise mitigation and grounding. Some background on myself is I have a mechanical engineering technology degree. But my job requires an ability to work with and troubleshoot electrical issues. Currently a customer is using a Servo motor on an end of arm tool for a 6-axis robot. This cell and all of its duplicates run perfectly fine in the build shops. Then run fine for a period of time once initially installed but begin have noise faults on the drive for the servo. So the known differences between the build shop and the customer sites are obviously supply power, there is also now a metal detector in close proximity. Then various other noisy machines around it. Various additional grounding has been added to attempt to get the noise away from the tooling and signal lines. Something that confuses me about the whole thing is that the low voltage analog signal shield is tied to both ends of the cable?? Meaning it has continuity to the ground and shield of the 480VAC power connector and cable? It also has continuity to the robot arm and robot base ground. This goes against all prior experience with robot drives and servos this to my understanding level, is encouraging current to flow across low voltage signal shield. It is also now tying what should be my "clean" grond to my "dirty" ground. We have also attached various additional ground straps and this has varying degrees of some cells it helps others it hurts. I am at a loss, does this make any sense or have I provide not enough information? Any input or help would be greatly appreciated.