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Video: How to create persistent variables in EcoStruxure™ Machine Expert (SoMachine)

Issue:
Need to save the values of variables after a PLC power cycle in EcoStruxure™ Machine Expert.

Product Line:
EcoStruxure™ Machine Expert (formerly SoMachine)

Cause:
Variables are losing their values after a PLC power cycle.

Resolution:
A persistent variables object needs to be added under "Applications Tree" in SoMachine, by right-clicking on "MyApplication".
All variables inside this object will become automatically persistent.

The commands for managing persistent variables are available in the menu Declarations. This menu is visible in EcoStruxure Machine Expert if a PersistentVars node is available in the Applications tree and the cursor is placed in the corresponding PersistentVars editor.

The persistent variable editor handles the order of persistent variables autonomously. It is possible to add or remove persistent variables without losing data independent of their position in the declaration.

If you delete a variable in the declaration, it will be replaced by an invisible placeholder variable in the process image. This placeholder variable, which has the same storage size as the deleted variable, helps to ensure that the subsequent variables keep their addresses. When a new variable is added at any position, it is added at the end of the list in the process image. This also helps to ensure that existing variables keep their addresses.

The modification of variables (name or data type) is handled like a deletion and a creation. This results in a placeholder gap and a new entry at the end of the list in the process image (not in the declaration). If variables are added from programs or function block instances by executing the command Add all Instance Paths, they are handled in the same way.

The persistent variable editor provides the following commands to determine the number of gaps and to remove them as well as functions to save and restore the variable values.

oAdd all Instance Paths

oReorder List and Clear Gaps

oSave Current Values to Recipe

oRestore Values from Recipe

Listed below are two FAQs that answer how to assign modbus addresses to variables:

https://www.se.com/ww/en/faqs/FA248757/