Variables

All variables within the entire system project are grouped as follows:

Variable	Description
Global variables	List all global variables that are used and accessible throughout the entire program
Retain Variables	List all variables that are to be retained when the system is powered down
Program variables	List the variables related to your specific selected program

For each variable, the Dictionary toolbox allows you to set the following parameters:

Field	Description
Name	The variable name
Value	All the variables in the Dictionary are animated with real-time values 1 Note that this column is only displayed when your application is running For more details, see "Variable Monitoring"
Type	The variable type (which can also be UDFB"User Defined Function Block" UDFB can be used as a sub-function block in another program of the application. It is described using FBD, LD, ST or IL language. Input / output parameters of a UDFB (as well as private variables) are declared in the variable editor as local variables of the UDFB or complex structure)
Dim.	To declare an array, you can specify dimension(s) for an internal variable
Attrib.	The variable attributes (Read Only, External, IN, OUT) as defined: Read Only: a variable set as Read Only is a constant (it cannot be modified in your PLC"Programmable Logic Controller" A Programmable Logic Controller, PLC, or Programmable Controller is a digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines. Used to synchronize the flow of inputs from (physical) sensors and events with the flow of outputs to actuators and events code, but it can be forced manually). Read Only variables can be mapped to Outputs but not to Inputs. This is because Inputs can change state and a Read Only variable would not be able to change its value to match the input state. External: this attribute is not used IN or OUT: Input or Output parameters of User Defined FunctionA function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances. Blocks
Init value	The variable initial value when you start your application (see more details here)
User Group	The variable user group (used for sorting variables)
HMI"Human-machine interfaces " Also known as computer-human interfaces (CHI), and formerly known as man-machine interfaces, they are usually employed to communicate with PLCs and other computers, such as entering and monitoring temperatures or pressures for further automated control or emergency response	Select variables to be used in HMI (see Map Variables to HMI)
Tag	The variable tag is a short comment, that can be displayed together with the variable name in graphical editors. See example here Edit the variable parameters Add the variable to your FBD"Function block diagram" A function block diagram describes a function between input variables and output variables. A function is described as a set of elementary blocks program Resize the rectangle to make the Tag and Description visible
Description	The variable description is a long comment text that describes the variable
Syb.	reserved