Endress+Hauser Liquiline CM44P - Page 112

Operation Liquiline CM44P
112 Endress+Hauser
Menu/Setup/Additional functions/Controller 1 ... 2
Function Options Info
Measured value Selection
Depends on Source of data
Factory setting
None
‣
Specify the measured value that should be
your disturbance variable.
You can use different measured values
depending on the data source. →  100
Zp Range of adjustment
depending on the selection
of the measured value
Proportional band ‐‐>
Z0 Zero point
Parameters
The Liquiline PID controller has been implemented in the serial structural form, i. e. it has the following
parameters:
• Integral action time T
n
• Derivative action time T
v
• Proportional band X
p
Setup Level = Advanced: With this setup level, you can also configure the following:
• Time constant T
wu
• Time constant α
• Width of the neutral zone X
n
• Width of the hysteresis range of the neutral zone X
hyst
• Clock time of the controller
Tn 0.0 to 9999.0 s
Factory setting
0.0 s
The integral action time specifies the effect of
the I-value
If Tn > 0 the following applies: Clock < Twu <
0.5(Tn + Tv)
The integral action time is the time needed in a step-function response to achieve a change in the manipulated
variable - as a result of the I effect - which has the same magnitude as the P-value.
y
t
PI
P
T
n
e
t
0
0
e = control deviation, e=w‐x (set point controlled variable)