Forcing controller in Auto
Forcing controller in Auto
(OP)
Just ran across a request by operations where they want to force a flow controller in Auto, such that the operator can not place it in Manual.
Looking at the process, they couldn't think of any reason why an operator would need to place it in manual. They have in the past, only for them to make bad product, because they've forgotten to place back in Auto.
I'm not comfortable not allowing the operator to have control when needed. To me it should be handled with operational procedures. (Written: Don't touch this!)
What's the best practice? Is it okay to force the controller in Auto (done in a DCS)? (of course, we would allow it when unit/phase is not running).
Looking at the process, they couldn't think of any reason why an operator would need to place it in manual. They have in the past, only for them to make bad product, because they've forgotten to place back in Auto.
I'm not comfortable not allowing the operator to have control when needed. To me it should be handled with operational procedures. (Written: Don't touch this!)
What's the best practice? Is it okay to force the controller in Auto (done in a DCS)? (of course, we would allow it when unit/phase is not running).
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RE: Forcing controller in Auto
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Forcing controller in Auto
Preventing operators from operating is not a good idea.
RE: Forcing controller in Auto
RE: Forcing controller in Auto
Moreover, if there are such anomalies, the control system should be designed to mitigate them or control through them.
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Forcing controller in Auto
For example:
A pressure control loop where you drop down from a high pressure to a lower pressure. If you put the loop in manual how would you prevent the output from over pressurizing the LP.
Sometimes a PID doesn't even need an operator faceplate.
RE: Forcing controller in Auto
Is that considered a "shut the line down" situation?
RE: Forcing controller in Auto