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Ask The Experts"Ask The Experts" is moderated on ControlGlobal.com by noted process control authority and CONTROL Columnist Bela Liptak. Liptak either answers the questions himself, or brings in one or more experts from his cadre of co-authors that worked with him on the Instrument Engineers' Handbook, Fourth Edition. Save yourself the hefty consulting fees by getting the answers to your questions here.

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When to use positioners in flow control

A positioner on an actuator that’s too slow for the process can be worse than none.

Aug 1, 2019

*Q: I stumbled on www.ControlGlobal.com while searching for information about PID control of flow. This question may have been answered, but the couple of threads I found didn't seem helpful specifically for my problem. I'm controlling gas flow with a flow sensor and an electrically actuated (servo) valve positioner. The positioner is slow, taking up to 90 seconds for full travel.*

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