Schema Compilation

A schema diagram is a representation of a control algorithm (or an algorithm fragment) to be executed by the controller hardware. In order for the algorithm to be executed, it must be translated or compiled into a form that the device's central processing unit (CPU) can understand. Design Pad G4 has a built-in compiler that does just that.

A schema can be processed individually as a standalone document, or it can be compiled during node configuration processing.

Process Schema

To process an individual schema document, select the Process Schema item in the Schema menu. Alternatively, you can press the corresponding button on the speed-bar menu (shown to the right.) Design Pad will then convert your schema into executable form

Process All Schemas

To process all the schema documents associated with a hardware interface file, select the desired .hwi document and click the Process All Schemas button in the speed-bar menu. Every time you hit a compile button, the executable program is generated and placed next to the .hwi file with the .run extension.  When you click the Process Schema or Process All Schemas button, Design Pad checks whether the .run file is up to date and regenerates the executable program if needed. 

During the compilation process, Design Pad G4 checks for errors or anomalies in your schema(s). For instance, Design Pad G4 will alert you if you have left an input pin disconnected or if you have combined an analog signal with a digital one. All the errors and warnings that Design Pad G4 may issue during compilation are described in the following section.

View Message Window

Design Pad G4 displays compilation errors, warnings, and notes in its Message window. Each line in the message window refers to an individual compilation error, warning, or note. When you select an item in the message window, Design Pad G4 will highlight the corresponding offending object(s) and/or signal(s) in the relevant schema document. Design Pad G4 will also re-center the schema view so that the highlighted object(s) appear at the center of the document window. You can toggle the visible state of the message window (shown or hidden) from the view menu. When you make the message window visible, Design Pad G4 displays a check mark next to the Message Window item in the View menu; it removes the check mark when the window is not visible. You can also toggle the visible state of the message window by pressing the corresponding button on the toolbar menu (shown to the right).

The message window is always displayed on top of other windows in the Design Pad G4 application environment. By default, it is docked on the bottom-left side of the screen. But it can be positioned (and resized) anywhere on the screen---it can be docked at the top, bottom, left side or right side of the client area or it can be floating anywhere on your computer screen (even outside of the application's client message). If the message window is docked and you wish to position it elsewhere, click on the window handle (two raised lines adjacent to the close button) and drag it to the desired location. To resize the message window while it is docked, click the right mouse button on the inner edge of the window and drag it to the desired location. When the message window is floating, you can resize it as you would any other window.