Manual

1
/
4
-DIN,
1
/
8
-DIN &
1
/
16
- DIN Controllers & Indicators - Product Manual
59305, Issue 7 – March 2014 Manual Tuning Page 119
7. Using manual control ensure that the valve is positioned away from its end stops.
8. Follow the instructions in the diagram below. At each stage, allow sufficient settling time
before moving on to the next stage.
Table 31. Manually Tuning Valve Control
Time
Process Variable
T
b
Time
Process Variable
T
a
START
Apply Power to
the load.
Does the
PV
continuously
Oscillate?
Note the time
interval T
a
Set  = 0.8%
Set  = T
a
Are the
Oscillations
decaying to
zero?
Multiply 
setting by 1.5
END
Note the period
of the decaying
oscillations (T
b
)
Multiply 
setting by 1.5
Set  = T
b
2
No
Yes
Yes
No
The controller is now tuned.
Fine-tuning may be required
to optimise the controllers
response