Safety Stop Mode (S1/S2 Open)

What does SA mean?

This alarm indicates that both safety input signals (S1 and S2) are in an open state, which triggers the safety stop function and causes the inverter output to shut off. This typically occurs as an intended safety action or due to a wiring issue, not an internal safety circuit fault.

• Emergency Stop button pressed, causing both safety contacts (connected to S1 and S2) to open.
• Guard interlock switch opened due to a door or panel access, interrupting the safety circuit loop.
• Safety relay output contacts (connected in series to S1/S2) failed to close or are de-energized.
• Broken wire or loose terminal connection in the external safety circuit loop connected to S1 and S2.
• External safety monitoring device (e.g., light curtain, safety scanner) detected an intrusion and opened its outputs.

Click steps to track your progress.

1. 1

   Verify that all emergency stop buttons are released and their contacts are closed (measure continuity across contacts).

2. 2

   Confirm all safety guard doors and access panels are securely closed, actuating their interlock switches.

3. 3

   Inspect the external safety relay (if present) for proper coil energization and contact closure (measure voltage across coil).

4. 4

   Measure continuity across terminals S1 and PC, and S2 and PC at the inverter to identify an open circuit in the loop (expect 24VDC or continuity).

5. 5

   Check the status indicators on any connected external safety devices (e.g., light curtains) for active alarms or tripped states.