Global/Local Variables

Video Tutorial

XG5000 allows the user to define Global and Local variables.

  • Global variables can be accessed from any Scan Program and Task.

  • Local variables can only be accessed from the Scan Program and Task it is defined in.

  • Variables must be declared before using them in Scan programs and Tasks.

Variable Type Description
VAR_GLOBAL Global variable type available to read/write.
VAR_GLOBAL_CONSTANT Global constant type that is read only.
VAR Local variable type available to read/write.
VAR_CONSTANT Local constant variable that is read only.
VAR_EXTERNAL Declaration to use a Global Variable in local program.
VAR_EXTERNAL_CONSTANT Declaration to use Global Constant in local program.
Step Action
1

In an open XG5000 Project, open the Global/Direct Variables file in the Project window.
2

Choose the Variable Kind for the Global variable.
3

Enter a variable name in the Variable column. This example has the variable name GlobalTest1.
4

Choose a Type for the Global variable.
5

An Address can be entered if this Global Variable accesses a Direct Variable address. This example shows the variable accessing Direct Variable Address %MX0.
6

An Initial Value can be given to the variable. This is the value of the variable on first scan of the CPU. This example shows an initial value of FALSE.
7

Select if the variable value is retained on power cycle of the CPU. Check the Retain box to store value on power cycle.
8

Check EIP/OPC UA if the variable is going to be used in EtherNet/IP P2P communication.
9

Add a comment to describe the variable.
Step Action
1

In an open XG5000 Project, open the Local Variables file in the desired Scan Program or Task. This example shows a Scan Program called NewProgram.
2

Choose the Variable Kind for the local variable.
3

Enter a variable name in the Variable column. This example has the variable name LocalTest1.
4

Choose a Type for the local variable.
5

An Address can be entered if this local variable accesses a Direct Variable address. This example shows the variable accessing Direct Variable Address %MX1.
6

An Initial Value can be given to the variable. This is the value of the variable on first scan of the CPU. This example shows an initial value of FALSE.
7

Select if the variable value is retained on power cycle of the CPU. Check the Retain box to store value on power cycle.
8

Check EIP/OPC UA if the variable is going to be used in EtherNet/IP P2P communication.
9

Add a comment to describe the variable.

To use a Global variable in a Scan program or Task, it must be declared as a VAR_EXTERNAL variable type for that Scan program.

  • This variable type can be found in the drop down when creating a variable.

  • VAR_EXTERNAL_CONSTANT is used the same way for a Global constant variable.

This Example shows declaring the VAR_EXTERNAL to allow the NewProgram Scan Program to use the GlobalTest1 global variable in code.

 

 

 

 

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