Asking about everyone's PID issue
Thread Content
We have a base-type regulator here that supplies pressure to the equipment; the set value is 4.83 Mpa, while the desired process value ranges from 4.0 Mpa to 4.2 Mpa. The valve should be fully open at this range, and it should be closed gradually when the pressure is between 4.2 Mpa and 4.83 Mpa. It also needs to be closed when the pressure exceeds 4.83 Mpa, and it should be opened slowly again to increase the pressure when it’s below 4.83 Mpa. How should I adjust the PID settings? (I know nothing about PID.)
Is (4.83-4.00)/4.83 the proportional band?
It can be regulated using PID within the range of 4.2–4.83; for cases where everything is on or off, simply set the value directly.
PID is difficult to tune; if linearity is good, try using range control
I don’t understand what the point is of setting a value of 4.83 MPa with so many switching conditions available.
This is too professional; I can’t answer it
It’s best to draw a diagram to see the control method, and then determine the control scheme
For example, if your pressure gauge has a range of 0-10 Mpa, and the proportional band is set to (4.83-4)/10*100, with a pressure setting of 4.83, then when the pressure drops to 4, the pressure valve will open fully.
It can be controlled in the following way: if 4.0≤pv≤4.2, PID manual, out=100%； if 4.2
This post was last edited by liaifeng on 2018-6-20 21:33. Is this the control logic, the control scheme for writing to the DCS? The approach proposed by the original poster belongs to a fuzzy control scheme; it should be similar to the analysis given above, and constitutes regional control!