I have installed two LCD displays for ABB PLC PM671, they were working fine, but suddenly one of them stopped working and shown fault, that caused stopped working other instruments connected through same power supply. I removed the power connector, all the other instruments working instantly. when I took faulty lcd to lab for repair, it starts normally, and no dysfunction was shown. I brought it back for plugging it shows same error again. I have replaced power plug, power cable, but same position.
What is the fault?

You still get the fault without being connected to the PM671. Is it panel mounted, maybe grounding or communication ?, have tried separate power source

Yes I did,I have connected it directly from power supply of PLC, it does turned ON and no fault was detected.
I also tuned it ON in Instrument workshop, there was no fault detected.
It does not taking the power supply from field, where it was previously installed.

You probably have a short circuit on the loop... Had the same problem with BECKOFF HMI.. Is the hmi connected to industrial pc? What kind of connection do you have? Hmi-pc-plc via cp link card!?