Answer / carl_ellis

What is the purpose of valve positioner. Explain 4 uses.

1) Use supply air pressure to ensure the correct valve
position through feedback control to overcome stiction or
forces on the valve plug.

2) Characterized the non-linear valve movement with respect
to the input signal, for instance, equal percentage or quick
opening

3) Provide position feedback to the control system via
conditioned process signal (4-20ma)

4) Provide adequate seat loading force to ensure tight
shut-off.

Carl Ellis
Measure First

Answer / as

Point No#2 The characterstics of valve for example
liner/equal percentage are defined by valve plug,cage shape
and not by valve positioner.

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