152 Program features Process controller PID1PID1 has two separate sets of parameters (40 PROCESS PID SET 1, 41 PROCESSPID SET 2). Selection between parameter sets 1 and 2 is defined by a parameter.In most cases when there is only one transducer signal wired to the drive, onlyparameter set 1 is needed. Two different parameter sets (1 and 2) are used, eg, whenthe load of the motor changes considerably in time. External/Trim controller PID2PID2 (42 EXT / TRIM PID) can be used in two different ways:• External controller: Instead of using additional PID controller hardware, the usercan connect PID2 output through drive analog output or fieldbus controller tocontrol a field instrument like a damper or a valve.• Trim controller: PID2 can be used to trim or fine tune the reference of the drive.See section Reference trimming on page 130. Block diagramsThe figure below shows an application example: The controller adjusts the speed of apressure boost pump according to the measured pressure and the set pressurereference.refktitdidFiltTerrVInvoh1ol1Speedreference%ref = 4010…...ACTPARFUNCDRIVEENTERLOCREMRESETREFACS6000...10bar4...20mA332DrivePID control block diagramExample:Pressure boost pump40014002400340044005PIDminPIDmax40144021AI1AI2IMOT%refActual valuesPIDSwitch9904 = 0Frequencyreference
