Instruction Parameters in FBD

All instructions in FBD are boxes.

Box Parameters

The instruction label is located in the topmost cell of the instruction. Note that labels are also assigned to parameters.

Small lines are shown jutting outward from the box at each parameter location. The assigned text of a parameter resides to the immediate left and right of the box, or, immediately above the box for box top parameters. The default parameter text, shown in red, indicates if logic flow is valid for the parameter.

The diagram above depicts the five regions of box instruction parameters which relate to the five different types of parameters. While there can only be one box top parameter and only one logic flow output parameter, the other three regions can contain multiple parameters.