CodeSys - Data Types

Variables.

Definition: Variables - They hold values that can change over time. A Variable is a name that is associated with a value.

Example: You could make a variable called temperature. The value in temperature can be changed.

Code Syntax: iTemperature := 90; // Notes- Temperature is set at 90 Degrees.

Variables can be of any data type. You could have made your variable called iTemperature a type DINT, LREAL, and more.

Variable Declaration: iTemperature : INT; //Notes- Value of data type INT.

Basic Data Types.

Definition: Data Types - They are simply type of a classification which tells the compiler how the programmer intends to use the data.

Example 1: A data type of BOOL, can only have 1 of 2 values. True or False.

Example 2: A data type of UINT, can have value from 0 to 65535.

NOTES: Most common data types could probably be debated but I find more often than not i use, BOOL, INT, DINT, LREAL. But you will use other types too.

Data Type - Enumeration.

Definition: Enumeration - Is a data type consisting a set of named values to replace normal values.

Example 1: Lets say you wanted a variable that did not show a number but showed a word that represented a value. This would be a great place for a Enum.

Example 2: Lets say you wanted something called eError. You wanted the eError to show a word to the program and not just a value. Lets say you wanted 0 = NA, 1=OK, -1 =error, -2 = Out of range.

Code Syntax:

TYPE eErrors : (

NA :=0, OK :=1, Error := -1, OutOfRange := -2

)INT; END_TYPE

Variable Declaration:

MyError : eErrors ; //Notes - This is how to Declare a custom Enum.

Data Type - Structures

Definition: Data Types - These types let a Variables hold more then 1 value at a time.

Example 1: Lets say you are making a simple video game. You could use a structure called Player. This player would have many variables inside it. Some of the things you might want your player to know is, Is it good or bad, what color is it, what is its health level, and more.

Example 2: Let's say you wanted to keep all your index values under one variable, like acceleration, deceleration, speed, distance. You would make a structure called Indexs or something.

Variable Declaration:

MyIndex_1: Indexs ; //1st index that has all of the var in it

MyIndex_2: Indexs ; //2nd index that has all of the var in it.