Self-Tuning Page - ABB C300 Operating Manual

...6 TUNING LEVEL
...6.1 Introduction to Self-tuning
Signal Noise
Values at
Start of
Execution
Controller Output
Information. 'At Set Point' self-tuning automatically calculates the P.I.D. terms based
on the process reaction during a self-tuning cycle. The controller output is
manipulated to give six process oscillations which are used to determine the tuning
parameters.
Information.
On initial conditions:
•
'Start-up' Tuning
output value set to give a stable process variable at least 10% of the engineering range
below the control set point.
•
'At Set Point' Tuning
must be close to the required set point and stable. The control output must also be
stable. However, for best results the Manual control mode can be used to stabilize the
output and the process value. The output must be adjusted slowly to allow process
response to the change, to bring the process variable to the required control set point.
The closer the process is to the set point, the more effective the self-tuning cycle.

6.2 Self-tuning Page

SELF
tUNE
Error
– – – – – –
No
Error
– – – – – –
16
Self-tune High Limit
Self-tune Low Limit
Fig. 6.2 'At Set Point' Self-tuning
– the controller is placed in the Manual control mode with the control
– may be initialized in the automatic mode but the process variable
Page Header – Self-tune.
Note. This page is not displayed if the Profile Function is
'ON' or
Error and Diagnostic Messages
If there are errors during self-tune, flashing error and
diagnostic messages are displayed. To clear message,
press the
Continued on next page
Hysteresis
Value
is set to '
Control Type
switch – see Table 6.1.
Hysteresis
Band
Output Step
Time
bNdLSS '