Safety, PDOs, and Variables

This topic is about PDOs, safety objects, and variable mapping.

• Within the PDO Selection / Mapping tab any safety-related objects are clearly identifiable by being in a yellow table. (Figure 1)
• Mapping a variable to an object is easily done by any of these methods:
  • Double-click the object and select or create a variable.
  • Right-click the object, select Map, and select or create a variable.
  • Drag an existing variable from the Dictionary to the object.

Variables assigned to a safety object must be Read Only.

Variables that are Read/Write do not appear in dialogs and drag-and-drop does not work.

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• • Once a variable is assigned, there is no further validation until the project is compiled.
  • That means a variable could be changed to Read/Write and still be assigned.
  • When you compile the project an error is generated.

Figure 1: PDO Selection/Mapping tab with FSoE objects (in yellow).

See Set Up a Variable to Monitor Safety Data.