14-11-2013, 05:07 PM
Its very clear from the manual that the screen should be connected to the "E" terminal (mains earth) at the VFD end ONLY (else you will get a ground loop).
As mentioned elsewhere here, ACM will not necessarily be connected to mains earth - it may well float from that for noise reasons (connected via a small capacitor to provide a low Z path for HF noise).
Problem with connecting the screen to ACM is that if any significant current is induced in the screen it will appear on the controller PCB analogue ground and may make operation erratic or even damage the board,
BTW, the letters ACM stand for "analogue common".
As mentioned elsewhere here, ACM will not necessarily be connected to mains earth - it may well float from that for noise reasons (connected via a small capacitor to provide a low Z path for HF noise).
Problem with connecting the screen to ACM is that if any significant current is induced in the screen it will appear on the controller PCB analogue ground and may make operation erratic or even damage the board,
BTW, the letters ACM stand for "analogue common".
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