What causes fault code VFD-COMM2 (VFD Communication Loss — EtherNet/IP)?

Ethernet cable disconnected or damaged — check RJ45 connectors and cable. IP address conflict on the network — another device has same IP. Managed switch port configuration issue — VLAN, speed, or duplex mismatch. PLC controller faulted or rebooted — all CIP connections dropped. Network bandwidth saturated — too many devices or excessive broadcast traffic. VFD Ethernet adapter module firmware incompatible with PLC firmware version

How do I fix fault code VFD-COMM2?

Check VFD network status LEDs — Link LED should be solid green, Activity LED should be flashing. Ping VFD IP address from engineering laptop — confirm basic connectivity. In PLC I/O tree, check VFD module status — look for connection faulted or RPI timeout. Verify IP address, subnet mask, and gateway on VFD match network plan. Check Ethernet cable with cable tester — replace if any pairs fail. Try a different switch port — eliminates switch port as the issue. Check comm loss action: Parameter for action on comm loss (fault/stop/hold last speed)

VFD Communication Loss — EtherNet/IP

VFD-COMM2

VFD lost EtherNet/IP connection to the PLC controller. CIP connection timed out. Drive entered configured comm loss action state.

high vfd plc allen-bradley

vfd communication ethernet/ip network cip

Probable Causes (ranked)

Ethernet cable disconnected or damaged — check RJ45 connectors and cable
IP address conflict on the network — another device has same IP
Managed switch port configuration issue — VLAN, speed, or duplex mismatch
PLC controller faulted or rebooted — all CIP connections dropped
Network bandwidth saturated — too many devices or excessive broadcast traffic
VFD Ethernet adapter module firmware incompatible with PLC firmware version

Fix Steps

1 Check VFD network status LEDs — Link LED should be solid green, Activity LED should be flashing
2 Ping VFD IP address from engineering laptop — confirm basic connectivity
3 In PLC I/O tree, check VFD module status — look for connection faulted or RPI timeout
4 Verify IP address, subnet mask, and gateway on VFD match network plan
5 Check Ethernet cable with cable tester — replace if any pairs fail
6 Try a different switch port — eliminates switch port as the issue
7 Check comm loss action: Parameter for action on comm loss (fault/stop/hold last speed)

Field Trick

Carry a small unmanaged 5-port switch in your toolbag. If you suspect the plant switch, plug the PLC and VFD directly into your switch. If comms work, the problem is the plant network infrastructure, not the devices.

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