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Using Intelligent Input Terminals
Operations
and Monitoring
4–28
PID ON/OFF and PID Clear
The PID loop function is useful for controlling motor speed to achieve constant flow,
pressure, temperature, etc. in many process applications. The PID Disable function
temporarily suspends PID loop execution via an intelligent input terminal. It overrides
the parameter A071 (PID Enable) to stop PID execution and return to normal motor
frequency output characteristics. the use of PID Disable on an intelligent input terminal
is optional. Of course, any use of the PID loop control requires setting PID Enable
function A071=01.
The PID Clear function forces the PID loop integrator sum = 0. So, when you turn ON
an intelligent input configured as [PIDC], the integrator sum is reset to zero. This is
useful when switching from manual control to PID loop control and the motor is
stopped.
CAUTION: Be careful not to turn PID Clear ON and reset the integrator sum when the
inverter is in Run Mode (output to motor is ON). Otherwise, this could cause the motor
to decelerate rapidly, resulting in a trip.
Option
Code
Terminal
Symbol
Function Name
Input
State
Description
23 PID PID Disable ON Disables PID loop execution
OFF Allows PID loop execution if A71=01
24 PIDC PID Clear ON Force the value of the integrator to zero
OFF No change to PID loop execution
Valid for inputs:
C001, C002, C003, C004,
C005
Required settings:
A071
Notes:
•
The use of [PID] and [PIDC] terminals are
optional. Use A071=01 if you want PID loop
control enabled all the time.
• Do not enable/disable PID control while the motor
is running (inverter is in Run Mode).
• Do not turn ON the [PIDC] input while the motor is
running (inverter is in Run Mode).
Example (requires input configuration—see
page 3–42
):
See I/O specs on page 4–6
.
PID
PIDC
12345L
PCS