Start: heating power switched off
The controller waits 1,5 minutes (
1
).
Heating power Y is switched on (
2
).
At the reversal point, the self-tuning
attempt is finished and control to the
set-point is using the new parameters.
Self-tuning at the set-point
a
The process is controlled to the
set-point. With the control deviation
constant during a defined time (
1
),
i.e. with the process value equal to the
set-point, the controller outputs a
reduced correcting variable pulse
(max. 20%) (
2
). After determination
of the control parameters using the
process characteristic (
3
), control is
started using the new parameters
(
4
).
Three-point controller
a
The parameter for heating and cooling
are determined in two attempts. The
heating power is switched on (
1
).
Heating parameters
Pb1
,
ti1
,
td1
and
t1
are determined at the
reversal point. The process is
controlled to the set-point (
2
). With
constant control deviation, the
controller provides a cooling
correcting variable pulse (
3
). After
determining its cooling parameters
Pb2
,
ti2
,
td2
and
t2
(
4
) from the
process characteristics , control operation is started using the new parameters
(
5
).
a
During phase
3
, heating and cooling are done simultaneously!
Operation
Self-tuning
18
Operating manual MIR-491
t
100%
Y
0%
X
W
start
r
1
2
t
reversal point
blinks
t
2
100%
Y
0%
X
W
1
3
blinks
4
r t
Start
r
t
+100%
Y 0%
-100%
X
W
t
reversal
point
Start
r
1
2
3
4
5
r t
