PLC basics

How a PLC runs your logic, and the tags, arrays, structures and Logic Classes it works with.

• The scan cycleRead inputs, run the rungs, write outputs. Repeat.
• Tags and data typesNamed values your rungs read and write.
• ArraysOne tag that holds a numbered list or grid of BOOL, DINT or REAL values.
• User-defined typesA structure groups related values, such as a motor's Run and Speed, into one tag.
• Logic ClassesWrite rungs once in a class, then call them for each machine, each use keeping its own values.