Problem in Kollmorgen Servo Drive Servostar 620

Dear Friends;

We have been using Danaher Motion Kollmorgen Servo drives "SERVOSTAR 620" working at Splicer units of our Corrugator machine to control the operation of Dancer roll via a servo motor. There is Resolver feed back from motor to drive and drive converts that signal to "Encoder output" signal which available at its connector “X5”. This encoder feed back signal then goes to PLC to detect the actual position of dancer roll.

This time we have a problem with two drives that they don't produces encoder output signal while all other operation are ok. We downloaded the program twice and completely cleaned the drives but problem is still there. At same places, other drives work well which means that motor, feedback cable and encoder feed back cable from drive to PLC is ok.

Can anyone please help me out how to resolve this issue? I sent mail to Danaher Motion but no answer from them.

Servo Drive Name Plate Image

Servo Motor Name Plate Image