Routines and blocks¶

A program can hold many routines, each in LD, ST or FBD, each open in its own tab.

• Main routine: runs every scan.
• Subroutine: runs when called with JSR (ladder) or JSR(Name); (ST). Shares the program's tags.
• Function (FC): has an interface of Input, Output, InOut and Temp variables. Call it with a CALL box or "Name"(In := x, Out => y);.
• Function block (FB): like a function plus Static variables that keep their value between calls. Each instance (a tag of the block's type) has its own copy: one motor-starter block, ten motors.

Inside a function or block, #Name refers to its own interface variables.

Create one with Project → Add routine or block…: choose the kind and the language. Rename or delete it from the project tree.

Examples: Traffic lights (routines) (a ladder main calling an ST sequence), Silo (function block), Motor starters (function block).