Hi everyone, we are having PC based Armature Balancing machine which uses Beckoff PLC for I/O transmission. We are facing a frequent error in the Beckoff PLC.We are using Beckoff BK8100 bus coupler along Input and output modules.The bus coupler communicates with the PC and intermittenly the bus couler I/O error starts blinking indicating the last card is faulty( Error code:4-led blinks 4 times leaves a pause and then blinks upto the last working card number) we have replaced all the cards eventually and still this error blinking comes very oftenly with no idea to lookout. We also observed that during the PC uploading the balancer software is the problem occurs frequently. SO kindly guide me in which path we can move to troubleshoot this issue.