PID overpressure control (Pr. 1370 and Pr. 1376)
● When the main valve is suddenly closed in the multi-pump function system, a sudden increase of
the pipe pressure may occur, and the pipes may be broken. To prevent fracture of the pipes, all
auxiliary motors are stopped when the feedback value exceeds the predetermined level.
● When the PID measured value reaches or exceeds the Pr. 1376 "Auxiliary motor stopping level"
and the elapsed time exceeds the Pr. 1370 "Detection time for PID limiting operation" while the
multi-pump function is activated, all operating auxiliary motors are disconnected and allowed to
coast to a stop regardless of the Pr. 579 "Motor connection function selection" setting. The motor
driven by the inverter continues its operation.
● After the auxiliary motor is stopped, the motor operation does not start while the PID measured
value is equal to Pr. 1376 setting or more even when the auxiliary motor starting condition is
The PID overpressure control function can be used when PID control is performed (reverse action
only) by the set point or measured value input using the multi-pump function.
Either the first or the second PID measured value is used according to the PID control selection.
When the control switches between the first PID control and second PID control, the measured
value to be used is also switched to continue the control operation.
Parameters referred to
Pr. 178 to Pr. 189
Pr. 190 to Pr. 196
Acceleration/deceleration reference frequency
Acceleration/deceleration time increments
Restart coasting time
Restart cushion time
(input terminal function selection)
(output terminal function selection)
(A) Application parameters
5 - 403