PID Controller Exercise 4— Defining Physics Modules
1. In the Flow Analysis Tree, right-click Physics and click Select Physical Models or click 
Physics Module in the Operations group from the Flow Analysis ribbon. The Physical Model Selection dialog box opens.
Physics Module in the Operations group from the Flow Analysis ribbon. The Physical Model Selection dialog box opens.2. Under Available Modules, select Flow and click 
3. Under Available Modules, select Heat and click
4. Under Available Modules, select Controller and click
5. Click Close to close the Physical Model Selection dialog box.
Controller Module
• The process variable for controller module is the temperature at the pipe outlet, which is defined using an expression as follows:
1. Select Common under Physics in the Flow Analysis Tree.
2. Select Expression Editor in Operations Tab. An Expression Editor dialog box appears.
3. Enter the following under Global Expressions
▪ pv=heat.T@pipe_outlet-273
4. Click OK to close the Expression Editor dialog box.
• The parameters of controller module are set as follows:
1. In the Flow Analysis Tree, select Controller.
2. In the Model tab, select the following values for the options listed:
▪ Setpoint—39
▪ Process Variable—pv
▪ Kp (Proportional Gain)—0.1
▪ Ki (Integral Gain)—0.1
▪ Time Step For Steady State Run—1 sec