I'm dealing with a natural gas compressor that's controlled by a Schneider ATV71 VFD and a M238 PLC that's been intermittently shutting down due to comm loss over the CANOpen bus. It's been going on since a lightning strike some time ago, according to our customer. After the strike, the drive and PLC were both replaced, but the compressor would occasionally go down due to comm loss. I'm fairly new to VFDs and PLCs, and new to my company, and I've inherited this problem. Some things that have been tried are replacing the shielded CANOpen cable, replacing DC power supplies, cleaning and verifying grounds, slowing the baud rate, and checking/replacing Line Terminating resistor on CANOpen terminals. I also checked for a Time Out parameter, but it seems this drive only has an adjustable Time Out for Modbus, not CANOpen. We're still getting a comm loss fault 2-5 times a week on that machine, and I'm hoping for some suggestions.
I'll be visiting the compressor again this week and have plans to replace the PLC, replace most of the wiring inside the enclosure(which houses both the VFD and PLC), and connect a direct ground to the CANOpen shielding to try to further eliminate any noise from the VFD. Are there other measures I can take to try to eliminate the issue?
I'll be visiting the compressor again this week and have plans to replace the PLC, replace most of the wiring inside the enclosure(which houses both the VFD and PLC), and connect a direct ground to the CANOpen shielding to try to further eliminate any noise from the VFD. Are there other measures I can take to try to eliminate the issue?