Here's a simple sample Structured Text ST program. It starts when the PLC application starts. It enables the motor (MC_Power), homes the axis (MC_Home), and then extends and retracts repeatedly with a time delay after each move.
Select the project that matches your version of Parker Automation Manager:
Under the "Online" tab at the top of the PAM window, make sure "Simulation" is checked. Whenever you go to login now, PAM will run a simulated device to run your project.
Make sure to uncheck this box when you want to connect and login to a physical PAC.
For PAM1.3 or earlier:
You can use an application with a CODESYS Control Win V3 device (You must add this). Under Online > Simulation. Then you can after Build (F11), click Online > Login.
This will create a virtual PLC and allow you to run PLC simulation (Play or F5). Here's some screen captures: