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ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

F71

Net Loss

Allen-Bradley · PowerFlex 4M Adjustable Frequency

What does F71 mean?

The drive has lost communication with its external network adapter or the network itself has failed. This means the drive is no longer receiving commands or transmitting status via the network, preventing remote control and monitoring.

Common Causes

  • Interruption of the Ethernet cable connection between the drive's network adapter and the network switch or PLC.
  • Network switch failure or power loss to the switch, disrupting communication to the drive.
  • Incorrect IP address, subnet mask, or gateway settings in the drive's network parameters (e.g., P9-01, P9-02, P9-03).
  • PLC or HMI controller program logic stopped or failed, ceasing communication requests to the drive.
  • The drive's network interface module (NIM) has failed or is incorrectly seated.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the physical Ethernet cable connection between the drive's network adapter and the network switch/PLC, ensuring secure seating.

  2. 2

    Confirm that the network switch is powered on and functioning, observing link status LEDs (e.g., green/amber activity lights).

  3. 3

    Ping the drive's configured IP address (e.g., P9-01) from a laptop to test basic network connectivity.

  4. 4

    Check network configuration parameters (e.g., P9-01 IP Address, P9-02 Subnet Mask) in the drive and compare with the network architecture.

  5. 5

    Review the PLC or HMI program to ensure communication instructions to the drive are active and correctly addressed.

Browse all codes in this manual (24)
Verified technical data. Last updated: April 2026

Related Faults

F100Parameter ChecksumF12Hardware OvercurrentF122I/O Board Fail
Source: Allen-Bradley PowerFlex 4M Adjustable Frequency
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