38
PID MANUAL TUNING USING THE APPROACH METHOD
This method is used when the process does not allow to run the Autotuning sequence or does
not allow to operate in On-Off mode used in Limit Oscillation method.
It is used to tune the
Reverse PID
as well as
Direct PID
. In
Bimodal PID
should be done
separately.
It is based on tuning the PID by approaching as follows:
- Set the setpoint
SP
of the process.
- Set
bP = 10%
with
ti
and
td = 0
and observe the process response.
If oscillates, increase bP until stabilization. If the response is slow, decrease bP.
As the controller is operating in pure proportional action (P), an Offset error will be produced
and displayed as the difference between the
SP
and the value of the process variable.
- When the process oscillation is small, increase the value of bP by 1 or 2 points, and then
proceed to determine the integral action
ti
.
- Select a high value of
ti
obtaining almost a pure response, i.e. 30.0 minutes.
- Then start reducing the
ti
slowly, starting in 5 to 5min. and at last en 1 to 1min. and check
that the Offset error is being corrected.
- If generating any disturbance in the process, i.e. modifing the setpoint, the oscillation
damping rate is 4:1 then the tuning is correct.
- Set the derivative time
td
between 1/5 and 1/10 of the time set in
ti
.
If necessary, the system response can be improved using the
Fuzzy-Logic function
.
Summary of Contents for HS-7000 Series
Page 4: ...4 This page has been left blank intentionally ...
Page 20: ...20 This page has been left blank intentionally ...
Page 105: ...105 NOTES ...
Page 106: ...106 NOTES ...
Page 107: ...107 NOTES ...