Mitsubishi Electric · Mitsubishi FR-E800 Variable Frequency Drive
The inverter output is shut off if, during PID control, the measured feedback value goes outside the limits set by Pr.131 (PID upper limit) or Pr.132 (PID lower limit), or if the absolute deviation from the setpoint exceeds Pr.553 (PID deviation limit). This protective function is not active by default and must be enabled via Pr.554. An erroneous PID signal can lead to unstable process control or unexpected shutdowns, indicating a sensor issue or incorrect parameter tuning.
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Measure the actual feedback signal directly at the inverter's analog input terminals (e.g., A1, A2) and compare it to the expected process value.
Verify the PID upper limit (Pr.131) and PID lower limit (Pr.132) parameters are set wide enough to accommodate normal process fluctuations.
Inspect the PID feedback sensor for damage, verify its power supply (e.g., 24VDC), and check its calibration against a known standard.
Check for proper shielding and grounding of the feedback signal cable to prevent electrical noise interference.
Temporarily switch to manual control or disable PID (if possible) to confirm the process can be controlled and the sensor is reading correctly.