Mitsubishi Electric NZ2GF2B-60TCTT4 User Manual page 190

(5) Operation with vibration ST
This section explains the operation of when a control response is oscillatory (vibration ST).
With vibration ST, PID constants are automatically corrected to settle a vibration when a control response
becomes oscillatory due to reasons such as the change in the characteristic of a controlled object and conditions
for operation.
The following table lists the operations of the module with vibration ST. (The listed operations are those under the
state where temperature is being controlled with the PID constants set.)
CH PID auto-correction status (b0 of RWr14 to RWr17) is turned 0 (OFF). In addition, CH Auto tuning status (RX20 to RX23) is
1
turned on.
2 PID constants are calculated based on a response waveform.
3 PID constants are set in the remote buffer memory and CH PID auto-correction status (b0 of RWr14 to RWr17) is turned 1 (ON).
4 CH Auto tuning status (RX20 to RX23) is turned off.
Temperature process value (PV)
Set value (SV)
CH□ Auto tuning status
(RX20 to RX23)
CH□ PID auto-correction status
(b0 of RWr14 to RWr17)
PID constants
(a) Conditions for self-tuning
Vibration ST is executed when the temperature process value (PV) goes outside the range that is judged as
unstable.
(b) Precautions
If vibration ST is executed on the following objects, incorrect PID constants may be determined:
• Controlled objects where a disturbance periodically occurs
• Controlled objects with strong mutual interference
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Oscillation detected
ON
OFF
Depends on previous
execution result
OFF
Controlled by the temperature control module
Operation with vibration ST
Response measurement
During self-tuning
Before change
PID constants calculated
ON
After change
Time