ControlMaster CM10, CM30 and CM50
Universal process controllers,
1
/
8
,
1
/
4
and
1
/
2
DIN
6 Basic Level
IM/CM/S–EN Rev. R
29
…Basic / …Loop 1 Control
Mode
Turns the
Autotune
functionality on or off.
When set to
On
, an
Autotune
can be started from the Operator level menus – see page 22.
Autotune
Autotune Operation
Autotune
is a user-activated feature that enables automatic setting of the controller
PID
parameters (see page 30) using an
'
at setpoint type
'
algorithm.
Autotune
changes the controller output and then monitors the process response to calculate
the optimum
PID
settings.
Autotune
uses a relay type function with hysteresis that initiates a controlled oscillation in the
process. New
PID
parameters are calculated and stored in the controller automatically.
Note
. To achieve the best results
from
Autotune
, switch the controller to
Manual
control mode (see page 5) and adjust the output until the PV is stable (close
to the normal setpoint) before initiating
Autotune
.
A
B
C
D
SP
PV
1
Set the first step value and dynamics required. For best results, select the largest initial
output step size that can be tolerated by the process.
2
Autotune
is enabled only if the control type is
PID
.
3
Start
Autotune
from the
Operator
menu.
4
Monitors a noise
A
and calculates a hysteresis value.
5
User-defined initial step in the output
B
. When the process exceeds the hysteresis
value the output is stepped down.
6
Adjusts output amplitude automatically
C
so PV disturbance is kept to minimum
required.
7
When consistent oscillation is established
D
, the Autotune process stops. Optimum
settings are calculated from the process dynamics monitored.
