ERR_PACKET_ALLOC

Firmware use only

Allen-Bradley · MicroLogix 1400 Programmable Controllers

What does ERR_PACKET_ALLOC mean?

This error is for firmware internal use only, indicating a failure to allocate a packet. This suggests a memory issue within the controller for Modbus TCP packet handling, preventing new packets from being processed or transmitted.

Common Causes

  • Insufficient free memory for Modbus TCP packet structures.
  • High volume of network traffic requiring more packet allocation than available.
  • Memory fragmentation within the controller.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Reduce network traffic volume directed at the controller's Modbus TCP interface.

  2. 2

    Review controller memory usage and optimize other applications if possible.

  3. 3

    Restart the controller to clear temporary memory issues and free packet resources.

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Verified technical data. Last updated: March 2026

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Source: Allen-Bradley MicroLogix 1400 Programmable Controllers