User Forum of Software BASEMENT

wld2008

User

Registered: 2014-09-12

Posts: 5

How to use a PID-controller to maintain the water surface elevation

I am learning the PID-controller in 2D simulations for tidal movement around a gate in the natural estuary.
The gate is located between a lake and the natural estuary.
The water surface elevation in the estuary changes with the time.
When there is no gate, the water flows freely between the lake and the estuary.
In time t1 the wse(water surface elevation)=s1,
in time t2 the wse=s2,
in time t3 the wse=s3.
in time t4 the wse=s4.
and
s1<s2<s3<s4.

When a gate is set, the water surface elevation in the lake maybe s-lake.

I need to close the gate when the s-lake>=s3 and keep the water surface elevation in the lake below s3.
I need to close the gate when the s-lake<=s2 and keep the water surface elevation in the lake above s2.
If the s3>s-lake>=s2 and the wse in the estuary >s-lake, the gate should be open until the s-lake=s3.
If the s3=>s-lake>s2 and the wse in the estuary <s-lake, the gate should be open until the s-lake=s2.

The main aim of the gate controlling is to promote the exchange of water between the lake and estuary.

My question is how to set the PID-controller? how to set the MONITORED_VARIABLE, the MANIPULATED_VARIABLE and related files?
Thanks a lot.