Static And Temp Variables In Plc

To better understand these variables and how they work let’s start by creating a simple plc programto help us understand what static and temp variables are Static variables and temporary variables are only available to logic block itself, and cannot be used as data interfaces between different blocks.

We will start by creating a function block fb and we will call this fb inside the main ob1 As a result, you can reuse a block you have already programmed for various. Use static when the variable must retain its value between block calls (state machines, edge detection, counters)

Static and Temp Variables in PLC

Use temp for intermediate calculations within a single scan.

This is one of the most confusing things for beginners in plc programming

You write a simple counter Then it resets “for no reason” Twincat 3 | plc variables the scope of a variable defines how and where you can use the variable You specify the scope of validity in the variable declaration

Learn the critical difference between static and temporary variables in plc programming in just 5 minutes. It looks like they are all for conventions and dont throw errors if you use them wrong but can someone run down what each should be used for. In this post i will discuss and explain the usage of the variable sections var_temp, var_stat and var constant. To do this, you can use the fact that a temporary structured variable contains the start values specified in the type definition after the fb is called and therefore serves as a template for.