Precision Digital PD540 - Manual (Page 32)

PV
Auto-Tuning the Heating/Cooling Outputs:
Auto-tuning of the heating/cooling outputs is the same process as the normal outputs. The PID heating/
cooling parameters wil l be calculated. The parameters for the PID derivation time (1.D) will be the same for
both the heating and cooling outputs.
Display During Auto-Tuning:
The MAN LED on the front panel will blink at a 500 ms time interval.
Changing the Set Point During Auto-Tuning:
If the set point is cha nged during the auto-tuning process, the original set point will be maintained for the
duration of the auto-tuning process. After auto-tuning is complete, the controller will change to the new set
point.
Changing PID Parameters During Auto-Tuning:
The PID values can be changed during the auto-tuning process. After auto-tuning is complete, it will then
use the auto-tune calculated PID values. Values changed after auto-tuning will remain set until auto-tuning is
run again.
Auto-Tuning Interruptions or Errors:
The auto-tuning process will end without effect for any of the following reasons:
- Auto-tuning forced to end (Example: Controller power down or stop condition)
- Open sensor (S.OPN) input error detected during the auto-tuning process
- Auto-tuning cycle exceeds 24 hours.
- Control changed to m anual (MAN) operation during auto-tuning.
This parameter affects the proportional value derived by auto-tuning. Reduce the AT-G
gain value and the cycle becomes more rapid, but more unstable. Increasing gain slows
system reaction time, but system stability increases.
Display Parameter Setting Range Unit Default Remark
AT
AT-G
Auto-Tuning OFF, ON ABS OFF AT Activation
AT Gain 0.1 to 10.0 ABS 1.0 Gain Value
Gain < 1
Gain = 1
Gain > 1
Fig 10: Auto-Tuning Gain
Auto-Tuning Group Parameter Summary
PD540 Series Nova Digital Process and Temperature Controller Instruction Manual
32