Structured Text and Program Architecture

Ladder is excellent for what it was designed for and painful for everything else. This course covers the everything else, and the program structure that holds it together.

You start with tasks (continuous, periodic and event) and what scan time and task overlap really mean for a running machine. Then Structured Text: syntax, IF and CASE, loops, calling instructions, and the jobs where it wins outright. State machines, recipe handling and maths-heavy routines are all far shorter and far clearer in ST.

There is a module on diagnostics that most training skips: GSV and SSV, the controller fault routine, major against minor faults, and logging enough about a failure that whoever is called out at 3am can act on it.

One note that matters if you are heading for the safety course: Structured Text is not available inside a GuardLogix safety task. Safety routines are ladder. This course is about the standard side of the controller.

1. 1

   Tasks, programs and routines

   Continuous, periodic and event tasks, scan time and task overlap, and how to lay out a program that the next person can follow.

   Available now 7 slides ~60 min 60 min lab
2. 2

   Structured Text basics

   Syntax and assignment, IF and CASE, FOR and WHILE, calling instructions from Structured Text, and the jobs where it beats ladder outright.

   Available now 7 slides ~60 min 60 min lab
3. 3

   Structured Text in practice

   State machines built on CASE, recipe handling, maths-heavy routines, and the readability rules that stop ST becoming write-only code.

   Available now 7 slides ~60 min 60 min lab
4. 4

   Diagnostics and fault handling

   GSV and SSV, the controller fault routine, major against minor faults, and logging enough about a failure that the next person can act on it.

   Available now 7 slides ~60 min 60 min lab
5. 5

   Putting a machine program together

   One machine program built from tasks, AOIs and ST routines, reviewed against a checklist and handed over the way a real job is.

   Available now 7 slides ~60 min 60 min lab

Lab times are approximate: they are a guide to how long the hands-on part usually takes, not a limit. You can ask for more lab time whenever you need it.