Endress+Hauser Liquisys M CPM253 User Manual

Commissioning Liquisys M CPM223/253
58 Endress+Hauser
PID controlling plus basic load dosing
If you select this function (PID + Basic) in field R231 the PID controlled dosage will not be
lower than the basic load value entered in field R2311.
a0008940
Fig. 39: Control characteristic PID controller with basic load dosing
APID with basic load
B Basic load
CPID
Commissioning
If you do not yet have any experience for setting the control parameters, set the values that
yield the greatest possible stability in the control circuit. Proceed as follows to optimize the
control circuit further:
• Increase the control gain K
p
until the controlled variable just starts to overshoot.
•Reduce K
p
slightly and then reduce the integral action time T
n
so that the shortest possible
correction time without overshooting is achieved.
• To reduce the response time of the controller, also set the derivative action time T
v
.
Control and fine optimization of the set parameters with a recorder
100 %
100 %
A
B
C
a0008924
Optimization of settings T
n
and K
p
A
B
Actual value
Time
1
2
3
T
n
too small
T
n
too large
K
p
too large
4
5
K
p
too small
Optimum setting
A
B
A
B
A
B
A
B
A
B
1
2
3
4
5

Endress+Hauser Liquisys M CPM253 Specifications

General

Brand	Endress+Hauser
Model	Liquisys M CPM253
Category	Transmitter
Language	English