P.pb, Int.t – West Control Solutions Pro-EC44 User Manual
Page 112
Pro-EC44 2-Loop Graphical Profile Controller & Recorder
Pro-EC44 Product Manual - 59540-1 October 2013
Page 105
5. Follow the instructions in the diagram below. At each stage, allow sufficient settling time
before moving on to the next stage. P.Pb is the Primary Proportional Band, Int.T is the
Integral Time Constant.
This method can also be used to tune PID loops. Set Derivative to approx. Ta / 4
Figure 61.
Manually Tuning
– PI Control
The controller is now tuned.
Fine-tuning may be required
to optimise the controllers’
response
Apply power to
the load
Does the
PV continuously
oscillate?
END
Note the time
interval T
a
START
Multiply
P.Pb
setting by 1.5
& Set
Int.T
= T
a
Are the
Oscillations
decaying to
zero?
Multiply
P.Pb
setting by 1.5
Note the period
of the decaying
oscillations (T
b
)
Multiply
P.Pb
setting by 1.5 &
Set
Int.T
Time
P
ro
c
es
s
V
a
riabl
e
T
b
Time
P
ro
c
es
s
V
a
riabl
e
T
a
Y
es
Y
es
No
No