What causes fault code SAF-004 (Safety PLC Firmware Mismatch)?

Firmware updated on one controller in redundant pair but not the other. Safety program developed on different firmware version. Firmware downgrade attempted without matching program revision. Replacement processor has factory firmware that's too old

How do I fix fault code SAF-004?

Check current firmware version vs program requirement in safety task properties. Update firmware to match program requirement using ControlFlash. If redundant pair, update BOTH processors to same firmware version. Verify safety signature after firmware update. Re-validate safety function after any firmware change per site safety plan

Safety PLC Firmware Mismatch

SAF-004

Safety controller firmware version does not match the safety program requirements. Safety functions may not execute correctly.

critical general allen-bradley

safety plc firmware mismatch controllogix

Probable Causes (ranked)

Firmware updated on one controller in redundant pair but not the other
Safety program developed on different firmware version
Firmware downgrade attempted without matching program revision
Replacement processor has factory firmware that's too old

Fix Steps

1 Check current firmware version vs program requirement in safety task properties
2 Update firmware to match program requirement using ControlFlash
3 If redundant pair, update BOTH processors to same firmware version
4 Verify safety signature after firmware update
5 Re-validate safety function after any firmware change per site safety plan

Field Trick

The safety task properties in Studio 5000 tell you EXACTLY what firmware version it needs. Compare that to what's on the processor. Match them and the fault clears.

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