What causes fault code AB-PF755-NETFLT (PowerFlex 755 Network Fault — Adapter Module)?

Network adapter module 20-COMM-E not seated properly in drive slot — vibration walked it loose. EtherNet cable disconnected or damaged at adapter module RJ45 port. IP address conflict on the EtherNet/IP network. PLC controller faulted or was downloaded — CIP connections dropped during download. 20-COMM module firmware incompatible with drive firmware — version mismatch. Network adapter module hardware failure — check module status LED

How do I fix fault code AB-PF755-NETFLT?

Check 20-COMM module status LEDs — NS (Network Status) should be steady GREEN for connected. Reseat the 20-COMM module in the PowerFlex 755 option slot — push firmly until latch clicks. Ping the adapter module IP address from engineering laptop. In Studio 5000 I/O tree, check connection status of the PF755 module definition. Verify firmware compatibility between 20-COMM-E and PowerFlex 755 main firmware — use Rockwell compatibility matrix. Check comm loss action parameter in drive — set to appropriate action (fault, coast, hold last speed). Try replacing 20-COMM module with spare if LED shows RED

PowerFlex 755 Network Fault — Adapter Module

AB-PF755-NETFLT

PowerFlex 755 lost communication with the PLC controller through its network adapter module (20-COMM-E EtherNet/IP or 20-COMM-D DeviceNet). Drive entered comm loss action state.

high allen-bradley vfd

allen-bradley powerflex 755 network 20-comm ethernet/ip communication

Probable Causes (ranked)

Network adapter module 20-COMM-E not seated properly in drive slot — vibration walked it loose
EtherNet cable disconnected or damaged at adapter module RJ45 port
IP address conflict on the EtherNet/IP network
PLC controller faulted or was downloaded — CIP connections dropped during download
20-COMM module firmware incompatible with drive firmware — version mismatch
Network adapter module hardware failure — check module status LED

Fix Steps

1 Check 20-COMM module status LEDs — NS (Network Status) should be steady GREEN for connected
2 Reseat the 20-COMM module in the PowerFlex 755 option slot — push firmly until latch clicks
3 Ping the adapter module IP address from engineering laptop
4 In Studio 5000 I/O tree, check connection status of the PF755 module definition
5 Verify firmware compatibility between 20-COMM-E and PowerFlex 755 main firmware — use Rockwell compatibility matrix
6 Check comm loss action parameter in drive — set to appropriate action (fault, coast, hold last speed)
7 Try replacing 20-COMM module with spare if LED shows RED

Field Trick

The 20-COMM-E module has two Ethernet ports for DLR ring topology. If you plug into port 1 and get nothing, try port 2 before you call it dead. Also, if you see the NS LED flashing GREEN rapidly, the module is getting power but has no IP — run BOOTP.

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