Declaring Variables
As can be seen from the GVL field list, each variable has a set of elements as follows:
쎲
Class
The class keyboard assigns the variable a specific property that defines how it is to be
used in the project
쎲
Identifier
Each variable is given a symbolic address, i.e.a name.This is referred to as the identifier.It
consists of a string of alphanumeric characters and ‘underscore’characters.The identifier
must always begin with a letter or an underscore character. Spaces and mathematical op
-
erator characters (e.g. +,-,*) are not permitted.
쎲
MIT-Addr
This is the absolute address referenced in the PLC.
쎲
IEC-Addr
The IEC syntax of the address.
쎲
Ty p e
Referrerstothedatatype,i.e.BOOL,INT,REAL,WORDetc.
쎲 Initial
The initial values are set automatically by the system and cannot be changed by the user.
쎲 Comment
Comments up to 64 characters may be added for each variable
If symbolic identifiers are not to be used in the program but only Mitsubishi addresses, then there
is no need to fill out the Global Variable List (GVL). However the program will no longer be truly
IEC61131-3 compliant.
Application Program Building a Project
4-10 MITSUBISHI ELECTRIC
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