About Variables

Variables are measurements or calculations attached to a given production unit that produce values either by time or event. Variables are created in Plant Applications Administrator. Using the Activities application, you can:

• Enter the values for these variables while performing an activity.
• Identify whether the values are within acceptable limits.
• Analyze the trend of the values using charts.
• Depending on the configuration in Plant Applications Administrator, receive alarm notifications and acknowledge them. For information, refer to About an Alarm Event Notification.

The following conditions apply when you enter or modify a variable value:

• You must configure a variable and include that variable on an autolog display using Plant Applications Administrator.
• You must create an activity for the autolog variable.
• If the data source of the variable is Historian or Calculation Manager, you must have the Admin privilege. Note that when the data source is Historian or Calculation Manager, the variable already contains a value, and you can only modify the value.
• If the data source of the variable is Autolog, you must have the Read/Write, Manager, or the Admin privilege.
• In Plant Applications Administrator, when the status of a production-based or user-defined event associated with the activity is set to a production status that has the Lock Event Data option enabled, you do not have the privilege to modify the autolog variables.
• In Plant Applications Administrator, if the LockUnavailableCells option is enabled for the display associated with the activity, only the users in the Administrator security group with an access Level other than Read can enter values for the modifiable autolog variables that have no available data.