CHAPTER 6 - DETAILED PARAMETER DESCRIPTION
After thefeedback inputhas beenchosen,youmustsetthe inputfunction
selected at P237 (to AI2) or P241 (to AI3).
ThePIDactionTypedescribedaboveconsidersthatthevariablefeedback
signal increases when the process variable also increases (direct
feedback). This is the most common used feedback type.
Whentheprocessvariablefeedbackdecreaseswhentheprocessvariable
increases (inverse feedback), it is required to program the selected
analog input for the PID (AI2 orAI3) as inverse reference: P239= 2 [(10
to 0) V/(20 to 0) mA] or P239 = 3 [(20 to 4) mA]. When the feedback is
throughAI2 and P243 = 2 [(10 to 0) V/(20 to 0) mA] or P243 = 3 [(20 to
4) mA] when the feedback is through AI3. When this setting is not
present, PID does not operate correctly.
It provides the setpoint via the and keys for the PID Regulator
(P203 = 1) provided that P221 = 0 (LOC) or P222 = 0 (REM) and the
inverter is in the Automatic mode. If it has been set to Manual Mode,
the speed reference is given by P121.
The value of P525 is maintained at the last set value (backup), even
when inverter is disabled or enabled with [P120 = 1 (Active)].
Once PID is inAutomatic mode, the Setpoint value for PID regulator is
entered into the CFW-09 via anyreference setbyP221 (LOCALmode)
orP222 (REMOTEmode).Particularly, mostof generalPIDapplications
uses the setpoint via theAI1 [P221 = 1 (LOC) or P222 = 1(REM)] or via
keys [P221 = 0 (LOC) or P222 = 0 (REM)]. Refer to
figure 6.47 - Block Diagram of the PID Regulator.
It sets the time constant of the Process Variable Filter.
Generally 0.1 will be a suitable value, excepting the process variable
signal has a too high noise level. In this case, increase this value
gradually by checking the result.
It defines the control action type:
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