6 Parameter Settings and Functions 
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6.3.4  Auto-tuning 
In PID control, auto-tuning processes the control subject's thermal characteristics and 
thermal response rate, and then determines the necessary PID time constant. Application 
of the PID time constant realizes fast response and high precision temperature control. 
6.3.4.1  Auto-tuning Start/Stop Setting [PAR2 → AT] 
  Auto-tuning automatically stores PID time constants upon termination. These PID 
time constants can then be modified by the user to suit their usage environment. 
  When auto-tuning is in progress, the AT lamp located on the front of the controller 
flashes in 1-second intervals. When auto-tuning finishes, the AT lamp automatically 
goes off and the auto-tuning parameter will return to 
OFF. 
  When auto-tuning is in progress and digital input (, ) feature is RUN/STOP 
or AUTO/MANUAL, auto-tuning will be automatically ended, if concerned DI is 
inputted or a sensor disconnection error occurs. (Restored the PID used prior to the 
auto-tuning session)_ 
Setting  Description 
Auto-tuning complete.   
Auto-tuning in progress. 
 
Setting 
Group 
Parameter  Setting Range 
Factory 
Default 
Unit 
/
- 
 
 
  Manual interruption or a sensor disconnection error when auto-tuning 
is in progress restores the PID time constant to the value used prior to 
the auto-tuning session. 
  Auto-tuning continues to run even if the temperature reading exceeds 
or falls below the input range. 
  When auto-turning is in progress, parameters can only be referenced 
and not altered. 
  Auto-tuning is not available in manual control.