What causes fault code AB-CLGX-FW (ControlLogix Firmware Flash Required After Replacement)?

New replacement module shipped with factory default firmware — different from project requirements. Module was pulled from spare stock with old firmware version. Project was developed on a newer firmware and replacement module is an older revision. After ControlFLASH update, module may need a power cycle to complete the update

How do I fix fault code AB-CLGX-FW?

In Studio 5000, right-click the module > Module Properties > General tab to see required vs. actual firmware revision. Open Rockwell ControlFLASH utility on the engineering PC. Browse to the module through the USB or Ethernet path. Select the target firmware version that matches the project requirement. Flash the module — do NOT interrupt the process (takes 2-10 minutes depending on module). After flash completes, power cycle the chassis if prompted. Re-download the program if the controller cleared its memory during the process

ControlLogix Firmware Flash Required After Replacement

AB-CLGX-FW

A replacement 1756 module has been installed but its firmware version does not match the project configuration. Module is faulted or inhibited until firmware is updated.

medium allen-bradley plc

allen-bradley controllogix 1756 firmware controlflash replacement upgrade

Probable Causes (ranked)

New replacement module shipped with factory default firmware — different from project requirements
Module was pulled from spare stock with old firmware version
Project was developed on a newer firmware and replacement module is an older revision
After ControlFLASH update, module may need a power cycle to complete the update

Fix Steps

1 In Studio 5000, right-click the module > Module Properties > General tab to see required vs. actual firmware revision
2 Open Rockwell ControlFLASH utility on the engineering PC
3 Browse to the module through the USB or Ethernet path
4 Select the target firmware version that matches the project requirement
5 Flash the module — do NOT interrupt the process (takes 2-10 minutes depending on module)
6 After flash completes, power cycle the chassis if prompted
7 Re-download the program if the controller cleared its memory during the process

Field Trick

Keep a USB drive with the ControlFLASH firmware files for every module type in your chassis. Download the firmware kit from Rockwell's website once per year. When you need to flash a module at 2 AM, you don't want to be downloading firmware files on a plant floor laptop with spotty WiFi.

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