3 Danfoss drive VLT 5000 are giving Warning 34 for Communication fault this occurred after a power surge .3 other drives on the same profibus network are ok.I have gone thru the manual and not success, we have copied parameters of one healthy danfoss to the faulty ones, tried even to change the profibus cable but the warning is still.Please i do believe the drives are ok can it be a hardware or software fault ? please assist