Mitsubishi Electric 800 Series Instruction Manual page 440

 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 satisfied.
NOTE
• 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.20 Acceleration/deceleration reference frequency, Pr.21 Acceleration/deceleration time increments
Pr.57 Restart coasting time, Pr.58 Restart cushion time
Pr.178 to Pr.189 (Input terminal function selection)
Pr.190 to Pr.196 (Output terminal function selection)
page 448
page 343
page 297
page 190
5. PARAMETERS
5.11 (A) Application parameters
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5
5
5
6
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