Introduction

What is a data instance reference?

At a Glance

A reference to a data instance by a value is an instance which does not have a name (symbol) or topological address.

This corresponds to an immediate value which can be assigned to a data type instance belonging to the EDT family.

Standard IEC 1131 authorizes immediate values on instances of the following data types:

• Booleans

  • BOOL

  • EBOOL

• integers

  • INT

  • UINT

  • DINT

  • UDINT

  • TIME

• reals

  • REAL

• dates and times

  • DATE

  • DATE AND TIME

  • TIME OF DAY

• character strings

  • STRING

The programming software goes beyond the scope of the standard by adding the bit string types.

• BYTE

• WORD

• DWORD

Examples of Immediate Values:

This table associates immediate values with types of instance