Cause : PID signal fault comes when any of PID upper limit (FUP), PID lower limit (FDN), and PID deviation limit (Y48) turns ON during PID control, inverter shuts off the output. This function is active under the following parameter settings: Pr.554 PID signal operation selection ≠ "0,10", Pr.131 PID upper limit ≠ "9999", Pr.132 PID lower limit ≠ "9999", and Pr.553 PID deviation limit ≠ "9999". This protective function is not active in the initial setting (Pr.554 = "0", Pr.131 = "9999", Pr.132 = "9999", Pr.553 = "9999").

1. Check if the measured PID value is greater than the upper limit (Pr.131) or smaller than the lower limit (Pr.132).
2. Check if the absolute PID deviation value is greater than the limit value (Pr.553).