You should use PID control in ATV21 / ATV212 drive to increase or decrease the speed automatically to maintain the set pressure in water pipe line.
It is important to have the pressure set point and pressure feedback for PID control in VFD.

1. Pressure set point - This is the pressure reference provided to the VFD through Analog input AI1. The analog input can be from drive keypad, 0 - 10VDC though potentiometer or 4 to 20 mA from PLC etc...
If you operate the VFD form the keypad(local mode), you can adjust the set point through up and down buttons given in the drive.
If you want to use external set point, the set point reference (0 - 10 VDC) should be connected between CC and VIB terminals.
a)you can connect a potentiometer between terminals PP(10VDC), VIB & CC to vary the reference from 0 to 10VDC.
b)If you give the reference form PLC you can connect the reference between VIB & CC directly.

2. Pressure feedback - The feedback should be connected between VIA & CC in VFD terminals. It is necessary to use analog pressure transducer(0-10V or 4-20mA or 0-20mA) give feedback to drive.

Please refer the attached technical resolution document for the wiring and setting of PID Control using ATV212 drive.

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