Control Builder Attributes explanations
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I also attached a screen cap of the "attributes" section of the F1 help. I'll paste it here for easier reference:
The variable value is not maintained after a restart, or a download of changes. Instead, it is set to the initial variable value. If the variable has no initial value assigned, it will be assigned the default data type value.
The variable value is maintained after a warm restart, but not after a cold restart. Control Builder sets retain on all variables by default. To override this, the attribute field must be left empty in declaration pane.
The parameter value is saved in the aspect directory, and retained after warm or cold restart.(*) Coldretain overrides the retain attributes in a structured data type.
You cannot change the value online once assigned. This attribute overrides the coldretain and retain attributes in a structured data type.
The variable will be hidden for an OPC client connected to an OPC server for AC 800M. This attribute is used for variable values not necessary to a supervisory system.
This attribute suppresses the code sorting feature for control module types. Do not use the nosort attribute unless you know the data flow characteristics in detail.
This attribute will let the variable retain its old value between two scans for control module types. The old and new value can be read by adding :old and :new to the variable name. be read by adding :old and :new to the variable name.
Source: 800xA Help Files, 800xA Getting Started Manual