Low Selector Switch (LSEL)
Low Selector Switch (LSEL)
(OP)
Attached is the Process Control Loop. I would like to know how the Low Selector Switch work.
Thanks.
Thanks.
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Low Selector Switch (LSEL)
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RE: Low Selector Switch (LSEL)
Good luck,
Latexman
RE: Low Selector Switch (LSEL)
I don't like the scheme as shown if both level and pressure controllers were simply PID (proportional, integral, derivative). With a simple PID scheme, the outputs from both pressure and level controllers would be fighting for the flow setpoint rate. A control algorithm with both high and low setpoint brackets (no output change when within limits) on each pressure and level would seem like an improvement. I have not played with the recent DCS algorithms but setpoint bracket configuration would exist.
RE: Low Selector Switch (LSEL)
Consider overrides via a safety control system. Normally the operator can select the controller on automatic mode that ignores the level and pressure controllers + the low output selector. Trip the pump on low level. Trip the inlet valve on high level. ...
RE: Low Selector Switch (LSEL)
The bigger turn-down ratio of the drum, the large control range control valve may be required, and the smaller turn-down ratio to the drum, the smaller control range control valve may be required.