what is output bias in control valve positioner ?

[ENG__AHMED]

after installing a new control valve positioner (fisher DVC6200) & while making auto travelling
it stopped at stage "adjusting output bias" and didn't continue auto travelling .

-what is meant by "output bias" & why it stopped ??

 

[danw2]

The term 'output bias' is mentioned as part of the auto-travel calibration routine, but the term is not defined.

If output refers to the positioner's pneumatic output, it could be a pressure offset needed to move off the zero % point (?).

The auto-travel section of the manual (below) lists some other errors that might warrant looking at for things to check, because I'm guessing that the auto-travel calibration did not complete because of this output bias error?

is anything moving at all during the test?
Linkage alignment issue?
inadequate air supply?

 

[IRstuff]

Is there some reason you can't talk to the supplier of the control valve positioner?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[Skogsgurra]

One good reason may be that EngTips is available for this kind of questions 24/7. And that you usually get answers a lot faster than the supplier's help desk (if it exists at all).

Gunnar Englund

http://www.gke.org

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