E2-25

Internal Error (SM560-S)

ABB · AC500-S Safety Controller

What does E2-25 mean?

The SM560-S Safety PLC has encountered an unspecified internal error. This indicates a system malfunction that prevents normal operation and requires intervention.

Common Causes

  • Internal hardware malfunction of the SM560-S, possibly related to memory or internal communication.
  • Firmware corruption, rendering the PLC unable to execute its internal routines correctly.
  • Transient voltage instability on the 24VDC supply rail causing CPU logic errors.
  • Unexpected software exception within the Safety PLC's operating system.
  • Component aging leading to intermittent internal failures.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Execute a full power down and restart of the entire control system, including the SM560-S module.

  2. 2

    2. Check for any overheating indicators on the SM560-S module or in its immediate enclosure.

  3. 3

    3. Verify the consistency between the loaded project in the PLC and the project on the engineering workstation.

  4. 4

    4. Update the SM560-S firmware to the latest available version from the manufacturer's website.

  5. 5

    5. Replace the SM560-S Safety PLC module if the error cannot be resolved through power cycling and software actions.

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Verified technical data. Last updated: March 2026

Related Faults

Source: ABB AC500-S Safety Controller