E.SAF

Internal Safety Circuit Fault

Mitsubishi Electric · FR-D700 Inverter

What does E.SAF mean?

This fault code indicates a detected malfunction within the inverter's internal safety circuit. When active, it causes the inverter to shut off its output to ensure a safe state, preventing drive operation. This is a critical internal error.

Common Causes

  • Internal self-diagnosis failure of the safety monitoring ASIC (Application-Specific Integrated Circuit).
  • EMI (Electromagnetic Interference) disturbance affecting the internal safety signal integrity on the control board.
  • Hardware degradation or component failure within the safety relay drive circuit.
  • Corrupted firmware module responsible for safety integrity monitoring.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Record current fault history and operating parameters (e.g., Pr. 093, Pr. 094).

  2. 2

    Power cycle the inverter, waiting 30 seconds after DC bus discharge (indicator OFF) before re-applying power.

  3. 3

    Verify all external safety inputs (S1, S2, STO) are correctly wired and provide expected feedback (e.g., 24VDC at S1, S2).

  4. 4

    Perform a safety circuit self-test if available via diagnostic software (e.g., using 'Safety Configuration Tool' via USB).

  5. 5

    Contact technical support with recorded fault codes and system configuration for advanced diagnostics.

Browse all codes in this manual (78)
Verified technical data. Last updated: March 2026

Related Faults

Source: Mitsubishi Electric FR-D700 Inverter