FUPLA (Function Block Diagram) Language

FUPLA is a graphical language specifically designed for controller programming in the Mervis IDE. It is highly suitable for continuous processes, such as HVAC regulation and basic logic interlocking. In a single project, you can freely combine FUPLA with Structured Text (ST) depending on which language best suits each specific task.

The FUPLA editor follows a logical “Signal Flow” structure from left to right:

• The Left Ladder (Inputs): This is where you place global variables or physical inputs that the program reads from.
• The Work Area (Canvas): The central space where function blocks are placed and interconnected. You can increase or decrease this area using the grip points in the corners.
• The Right Ladder (Outputs): This area holds the variables to which you want to write results.

To build an executable program, follow these standard proceedings:

• Variable Placement: Right-click a field in the left ladder to insert a variable to read.
• Adding Blocks: Right-click in the working area and select “Add library box”. You can use filters or arrow keys to find blocks like PID controllers, timers, or logic gates.
• Wiring: Link output ports of variables in the ladder to input ports of blocks by clicking and dragging a “wire”. Similarly, connect block outputs to the next block or to the right ladder for final output.
• Configuration: Click on any function block to adjust its properties in the property grid, such as toggling pin visibility or setting fixed default values.