Auto Tuning Function - Mitsubishi Electric MELSEC iQ-F FX5 User Manual

4.12

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.
Operations during auto tuning
The following operations are implemented if auto tuning during temperature rise.
Process value (PV)
Set value (SV)
AT start
Settings related to the auto tuning
The auto tuning can be executed when the following setting have been configured. Configure the other settings to the values
used for actual operations because actual control starts on completion of the auto tuning.
When "0" has been set for 'CH1 Proportional band (P) setting' (Un\G431) or 'CH1 Heating proportional band (Ph) setting'
(Un\G431), auto tuning is not implemented.
• "Input range setting" of "Control basic parameters" in "Application Setting"
• "Set Value (SV) Setting" of "Control basic parameters" in "Application Setting"
• "Upper limit output limiter" of "Limiter setting" in "Application Setting"
• "Lower limit output limiter" of "Limiter setting" in "Application Setting"
• "Cooling upper limit output limiter" of "Heating/cooling control setting" in "Application Setting"
• "Output change ratio limiter" of "Limiter setting" in "Application Setting"
• "Sensor Correction Value Setting" in "Application Setting"
• "Control output cycle setting" of "Control basic parameters" in "Application Setting"
• "Cooling control output cycle setting" of "Heating/cooling control setting" in "Application Setting"
• "Primary Delay Digital Filter Setting" in "Application Setting"
• 'CH1 AUTO/MAN mode shift' (Un\G518)
• "AT Bias" of "Auto tuning setting" in "Application Setting"
• "Normal Operation/Reverse Operation Setting" in "Application Setting"
Storing the calculation values after auto tuning
After the completion of the auto tuning, calculation values are stored in the following buffer memory areas.
• 'CH1 Proportional band (P) setting' (Un\G431)
• 'CH1 Heating proportional band (Ph) setting' (Un\G431)
• 'CH1 Cooling proportional band (Pc) setting' (Un\G439)
• 'CH1 Integral time (I) setting' (Un\G432)
• 'CH1 Differential time (D) setting' (Un\G433)
• 'CH1 Loop disconnection detection judgment time' (Un\G537)
*1 A value that is twice as large as the value in 'CH1 Integral time (I) setting' (Un\G432) is automatically set. However, when this setting has
been set to 0s at the auto tuning, the loop disconnection detection judgment time is not stored.
4 FUNCTION
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4.12 Auto Tuning Function
AT finish
*1
Time