Auto Tuning Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

1.11

Auto Tuning Function

The temperature control module automatically sets the best PID constants. In the auto tuning, the control output is turned ON
and OFF, and PID constants are calculated depending on the hunting cycle and amplitude that occur when overshoots and
undershoots of the temperature process value (PV) to the set value (SV) are repeated.
Auto tuning operation
The temperature control module operates as follows:
Set value (SV)
(Temperature process value (PV))
'CH1 Auto tuning command'
(Y4)
'CH1 Auto tuning status'
(X4)
(1) The module starts the auto tuning.
(2) The first overshoot and undershoot are ignored.
(3) The module collects data from the point where the temperature process value (PV) reaches the set value (SV) after the first overshoot and undershoot.
(4) The module ends the auto tuning when PID constants and the loop disconnection detection judgment time are set after the data collection.
The time taken for the auto tuning depends on a controlled object.
1 FUNCTIONS
38
1.11 Auto Tuning Function
Temperature process
value (PV)
(1)
ON
OFF
ON
OFF
Executed in a program
Executed by the temperature control module
(2)
(3)
Auto tuning in execution
(4)
Time
Temperature
control