ControlMaster CM30, CM50 and CMF310
Universal process controllers,
1
/
4
,
1
/
2
DIN and fieldmount
7 Advanced Level
IM/CM/ED–EN Rev. X
53
…Control / …Loop 1 (2) Control / …Adaptive Control
Mode
Turns adaptive control
On
or
Off.
Critical Gain
Critical Period
Normally set by the autotuner, but can be set manually if necessary. A valid setting must be
entered (either manually or using
Autotune
[see page 29) for the adaptive controller to
function.
Manual Calculation of
Critical Gain
and
Critical Period
1
Put the controller into
Manual
control mode.
2
Set the integral and derivative terms to off.
3 Set
the
Proportional Band
to 100 % – see page 30.
4 Adjust the controller's output signal manually until the process variable equals the
setpoint.
5
Read the current controller output value.
6 Set
the
controller's
Manual Reset
parameter to the value of the output – see page 30.
7
Put the unit into
Auto
control mode.
8
Change setpoint by a few percent (as the setpoint is changed in each iteration, keep the
value relatively constant by alternating increases with decreases).
9
Observe the process variable and the output signal to see if the system oscillates.
10 If the system oscillates with a decreasing amplitude, decrease the proportional band
and go to step 8.
11 If the system oscillates with a increasing amplitude, increase the proportional band and
go to step 8.
12 If the system oscillates with a constant amplitude, read the controller's oscillation period
time. This is the setting of the
Critical Period
parameter.
Read the proportional band (Pb) setting and calculate the
Critical Gain
(Kc) as follows:
Reset
Resets the adaptive controller's internal parameters and process model to their default
settings.
Misc.
Loop Monitor
A control loop performance monitor can be enabled to monitor the control loop for abnormal
oscillations and creates a diagnostic warning if any occur. This function is automatic and
does not require any user set up after it is activated.
R
S
P
S
tep Action
Remote setpoint step behavior. Determines how the
PID
(see page 30) algorithm responds
to a step change in the remote setpoint value.
No P&D
During a step change in the remote setpoint value, the integral term only is applied.
P&D
During a step change in the remote setpoint value proportional, integral and derivative terms
are applied.
K =
C
100
Pb
