Mitsubishi Electric · FR-D700 Inverter
The safety stop function has been activated, resulting in an immediate shutdown of the inverter outputs. This critical safety measure is typically triggered by an external safety device or a wiring issue across terminals S1 and SC, or S2 and SC, indicating an open circuit in the safety chain. If misconfigured or experiencing an internal failure, it can prevent normal operation or compromise machinery safety.
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1. Identify and verify the state of all associated external safety devices (e-stop buttons, light curtains, interlocks) for activation.
2. Measure voltage at the inverter's STO (Safe Torque Off) input terminals (e.g., S1, S2) to determine if a signal is present (e.g., 24VDC).
3. Review the wiring of the safety input circuit for continuity, shorts, or damaged insulation.
4. Check the status of the safety PLC or safety relay controlling the inverter's safety inputs.
5. Inspect inverter safety-related parameters (e.g., Pr. 350-353) to ensure correct configuration for the application.