
1. Ensure that the controller is correctly configured
and installed.
2. Ensure that the proportional band “PB” is not set at
“0”.
3. Press the return key for at least 6 seconds (maxi-
mum 16 seconds). This initializes the auto-tune
function. (To abort auto-tuning procedure, press
and release the return key).
4. The decimal point in the lower right hand corner of
the PV display flashes to indicate that auto-tuning
is in progress. Auto-tune is complete when the
flashing stops.
5. Depending on the particular process, automatic
tuning may take up to two hours. Processes with
long time lags will take the longest to tune.
Remember, while the display point flashes, the
controller is auto-tuning.
NOTE: If an AT error( ) occurs, the automat-
ic tuning process is aborted due to the system operat-
ing in ON-OFF control mode (PB=0). The process
will also be aborted if the set point is set too close to
the process temperature or if there is insufficient
capacity in the system to reach the set point (e.g.,
inadequate heating power available). Upon comple-
tion of auto-tuning, the new PID settings are auto-
matically entered into the controller's non-volatile
memory.
8
Proportional Band
Symptom Solution
Slow Response Decrease PB Value
High Overshoot or Oscillations Increase PB Value
8–4 Automatic Tuning
Tuning Guide
8–5 Manual PID Adjustment
Although the auto-tuning function will select control
settings which should prove satisfactory for the
majority of processes, you may find it necessary to
make adjustments to these settings from time to time.
This may be the case if some changes are made to the
process or if you wish to fine-tune the control settings.
It is important, prior to making changes to the control
settings, that you record the current settings for future
reference. Make only slight changes to one setting at
a time and observe the results on the process. Because
each of the settings interacts with the others, it is easy
to become confused with the results if you are not
familiar with process control procedures.
Integral Time ( eset)
Symptom Solution
Slow Response Decrease Integral Time
Instability or Oscillations Increase Integral Time
Derivative Time ( ate)
Symptom Solution
Slow Response or Oscillations Decrease Derivative. Time
High Overshoot Increase Derivative Time