Safety circuit fault

What does E.SAF mean?

This safety circuit fault appears when the internal safety circuit malfunctions, or when protective lines (S1-PC, S2-PC) are open. It can also be triggered by a prolonged 24V external power supply start-up time. This is a critical safety integrity issue, preventing normal operation.

• Safety input terminals (S1-PC, S2-PC) are open, indicating an emergency stop button pressed, safety gate open, or external safety relay tripped.
• Internal fault within the inverter's STO (Safe Torque Off) or SBC (Safe Brake Control) circuit preventing safe operation.
• External 24VDC power supply instability or dropout causing the safety circuit to lose its reference voltage for a prolonged period.
• Incorrect wiring or high resistance connection to the safety input terminals S1-PC and S2-PC from external safety devices.
• Malfunctioning safety relay (e.g., external safety monitor, programmable safety controller) failing to provide proper signal to S1-PC/S2-PC.

Click steps to track your progress.

1. 1

   1. Verify the status of all external safety devices connected to S1-PC and S2-PC (e.g., E-stop buttons, safety interlocks, light curtains) and ensure they are all in the 'safe' or 'ready' state, providing a closed circuit.

2. 2

   2. Measure the voltage between S1-PC and PC, and S2-PC and PC terminals. It should be approximately 24VDC when the safety circuit is active and closed.

3. 3

   3. Check the stability of the external 24VDC power supply by monitoring its voltage output with an oscilloscope or a high-speed multimeter for drops below 20VDC.

4. 4

   4. Inspect all wiring and connections to the S1-PC and S2-PC terminals for continuity, proper termination, and absence of shorts to ground or other potentials.

5. 5

   5. Temporarily bypass external safety devices (only for troubleshooting, following strict safety protocols) by jumpering S1-PC to PC and S2-PC to PC. If the fault clears, the issue is external to the inverter.