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Table Of Contents
Mastering PLC Programming
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It is often necessary to have an immutable variable. In other words, it is often necessary to declare a variable, assign it a value, and ensure that the value never changes. Possible examples of required constants are as follows:
This list is by no means comprehensive, nor will you always need to declare constants for the preceding bullet items. Whether or not you declare a constant is up to you and the application that you’re developing. In short, you will declare a constant when you want to add a level of protection so that a variable’s value never changes.
Declaring a constant is very simple. You can either use the Auto Declare tool and simply check the CONSTANT box, or you can declare one manually with the following syntax:
VAR CONSTANT const: INT :...