Data definitions

The IEC61131-3 specification provides access to memory through named variables.

IEC61131-3 names for variables follow these naming conventions:

Contains a minimum of six characters (
FactoryTalk Design Workbench
applications support a minimum of one character).
Starts with an underscore or a letter (A–Z), followed by underscores, letters, or numbers.
Supports lowercased letters (a–z) if they are case-sensitive (A = a, B = b, C = c...).

Micro800

controllers fully comply with this definition, support the lowercased option, and extend names to up to 40 characters.

Data variables in IEC61131-3 can be defined to be accessible to all programs in a resource or controller, or to be limited to functions in a single program.

Access paths can be configured to define the location of data in a system to pass the data between multiple resources or controllers.

Micro800

controllers comply by offering program-scoped and controller-scoped data, and they allow configuration of access paths using produced or consumed data.