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ErrorLib — Industrial Fault Code Library

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SRVO-231

Safety Chain 2 Abnormal

Fanuc · R-30iB Mate + Mate Plus Robot

What does SRVO-231 mean?

A mismatch has occurred between duplicate safety signals. Specifically, a contact on the chain 1 side (e.g., between EES1 and EES11, or EAS1 and EAS11) is open, while the corresponding contact on the chain 2 side (e.g., between EES2 and EES21, or EAS2 and EAS21) is closed. This condition indicates a potential failure or discrepancy in one of the redundant safety circuits, compromising safety integrity.

Common Causes

  • Safety Chain 2 has detected an abnormal condition, interrupting normal operation.
  • Similar to Safety Chain 1, this fault is related to the second safety interlock circuit, indicating an issue with its components or wiring.
  • The control system has halted operation due to a fault in the secondary safety monitoring system.
  • Inspect all components and wiring connected to Safety Chain 2 for faults.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check any other SRVO-266 through SRVO-275 and SRVO-370 through SRVO-385 alarms issued simultaneously to identify the specific signal with the mismatch.

  2. 2

    Take corrective action(s) as described for any concurrently issued alarms.

  3. 3

    Do not reset the chain error alarm until the failure is identified and repaired to ensure safety.

  4. 4

    After correcting the cause of the alarm, perform the chain error reset procedure as described in the manual.

Browse all codes in this manual (53)
Verified technical data. Last updated: April 2026

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Source: Fanuc R-30iB Mate + Mate Plus Robot
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