PID is easy
8.7 Commissioning the PID controller
Easy Book
190 Manual, 03/2014, A5E02486774-AF
Reaction to error Defines the behavior of the valve when an error is detected or when the PID loop is
reset. If you select to use a substitute position, enter the "Safety position". For analog
feedback or analog output, select a value between the upper or lower limit for the
output. For digital outputs, you can choose only 0% (off) or 100% (on).
Scale Position
Feedback
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• "High end stop" and "Lower end stop" define the maximum positive position (full-
open) and the maximum negative position (full-closed). "High end stop" must be
greater than "Lower end stop".
• "High limit process value" and "Low limit process value" define the upper and lower
positions of the valve during tuning and automatic mode.
• "FeedbackPER" ("Low" and "High") defines the analog feedback of the valve
position. "FeedbackPER High" must be greater than "FeedbackPER Low".
Advanced Monitoring process
Sets the warning high and low limits for the process value.
PID parameters If the user wishes, he can enter his own PID tuning parameters in this window. The
“Enable Manual Entry” check box must be checked to allow this.
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"Scale Position Feedback" is editable only if you enabled "Feedback" in the "Basic" settings.
Commissioning the PID controller
Use the commissioning editor to configure the PID controller for autotuning at start
up
and for autotuning during operation. To open the commissioning editor, click the icon
on either the instruction or the project navigator.
Table 8- 11 Sample commissioning screen (PID_3Step)
• Measurement: To display the setpoint, the
process value (input value) and the output value in a
real-time trend, enter the sample time and click the
"Start" button.
• Tuning mode: To tune the PID loop, select either
"Pre-tuning" or "Fine tuning" (manual) and click the
"Start" button. The PID controller runs through
multiple phases to calculate system response and
update times. The appropriate tuning parameters are
calculated from these values.
After the completion of the tuning process, you can
store the new parameters by clicking the "Upload PID
parameters" button in the "PID Parameters" section of
the commissioning editor.
If an error occurs during tuning, the output value of the
PID goes to 0. The PID mode then is set to "inactive"
mode. The status indicates the error.
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