Modelica_StateGraph2.Examples.Applications.ControlledTanks

Package Content

Name	Description
ControlledTanks1
ControlledTanks2
Internal	Utility components for the examples

Modelica_StateGraph2.Examples.Applications.ControlledTanks.ControlledTanks1

Information

With this example the controller of a tank filling/emptying system is demonstrated. This example is from Dressler (2004), see Literature which in turn is based on an example model from Karl Erk Arzen of JGraphCharts.

The basic operation is to fill and empty the two tanks:

1. Valve 1 is opened and tank 1 is filled.
2. When tank 1 reaches its fill level limit, valve 1 is closed.
3. After a waiting time, valve 2 is opened and the fluid flows from tank 1 into tank 2.
4. When tank 1 is empty, valve 2 is closed.
5. After a waiting time, valve 3 is opened and the fluid flows out of tank 2
6. When tank 2 is empty, valve 3 is closed

The above "normal" operation can be influenced by three buttons:

• Button start starts the above process. When this button is pressed after a "stop" or "shut" operation, the process operation continues.
• Button stop stops the above process by closing all valves. Then, the controller waits for further input (either "start" or "shut" operation).
• Button shut is used to shutdown the process, by emptying at once both tanks. When this is achieved, the process goes back to its start configuration. Clicking on "start", restarts the process.

The tank controller has some safeguards to prevent the tanks to overflow even if there are errors in the control system:

• Valve 1 is closed in any case, if the fill level of tank 1 is 1.01*fill limit.
• Valve 2 is closed in any case, if the fill level of tank 2 is 1.01*fill limit.

The default simulation time is 900 s. The result can be animated. For this, set in Dymola in the command window: "animationSpeed(speed = 50)".

Extends from Internal.PartialControlledTank.

Modelica definition

model ControlledTanks1
  extends Internal.PartialControlledTank;
  Internal.TankController1 tankController(
  limit1=0.9*tank1.height,
  limit2=0.9*tank2.height,
  waitTime=50,
  minLevel=0.01);

  Modelica_StateGraph2.Blocks.Interactive.RadioButtonSource start(
                                                    reset={stop.on,shut.on},
    buttonTimeTable={20,280});
  Modelica_StateGraph2.Blocks.Interactive.RadioButtonSource stop(
                                                   reset={start.on,shut.on},
    buttonTimeTable={220,650});
  Modelica_StateGraph2.Blocks.Interactive.RadioButtonSource shut(
                                                   reset={start.on,stop.on},
    buttonTimeTable={700});
  Modelica.Blocks.Sources.RealExpression level1(y=tank1.level);
  Modelica.Blocks.Sources.RealExpression level2(y=tank2.level);
equation 

connect(level1.y, tankController.level1);
connect(level2.y, tankController.level2);
connect(tankController.valve1, valve1.open);
connect(tankController.valve2, valve2.open);
connect(tankController.valve3, valve3.open);
connect(start.on, tankController.start);
connect(stop.on, tankController.stop);
connect(shut.on, tankController.shut);
end ControlledTanks1;

Modelica_StateGraph2.Examples.Applications.ControlledTanks.ControlledTanks2

Information

This is the same model as "ControlledTanks1". The only difference is how the tank controller is implemented:

• All signals are reported via a signal bus.
• The controller is hierarchically structured for the different tasks.

Extends from Internal.PartialControlledTank.

Modelica definition

model ControlledTanks2
  extends Internal.PartialControlledTank;
  Modelica_StateGraph2.Blocks.Interactive.RadioButtonSource start(
                                                    reset={stop.on,shut.on},
    buttonTimeTable={20,280});
  Modelica_StateGraph2.Blocks.Interactive.RadioButtonSource stop(
                                                   reset={start.on,shut.on},
    buttonTimeTable={220,650});
  Modelica_StateGraph2.Blocks.Interactive.RadioButtonSource shut(
                                                   reset={start.on,stop.on},
    buttonTimeTable={700});
protected 
  Internal.SignalBus bus;
public 
  Internal.TankController2 tankController(
  limit1=0.9*tank1.height,
  limit2=0.9*tank2.height,
  minLevel=0.01,
  waitTime=50);
  Modelica.Blocks.Sources.RealExpression level1(y=tank1.level);
  Modelica.Blocks.Sources.RealExpression level2(y=tank2.level);
equation 
  connect(level1.y, bus.level1);

  connect(level2.y, bus.level2);
connect(shut.on, bus.shut);
connect(stop.on, bus.stop);
connect(start.on, bus.start);
connect(valve1.open, bus.valve1);
connect(valve2.open, bus.valve2);
connect(valve3.open, bus.valve3);

connect(tankController.bus, bus);
end ControlledTanks2;