You can use some types of Variable in a similar way to internal Points. Like internal points, Variables only exist within the master station software. You can use Variables in Logic programs, Value Maps, and so on. However, unlike internal points, Variables do not have the additional ‘overheads’ associated with points, such as the ability to generate events or alarms.
Create and configure a Variable on your system if you require:
- a value that is not associated with plant
- a value that does not need any of the ‘overheads’ associated with internal points (see the bullet list in the Points section, above)
- a value that can be changed when required, including, if need be, on a scheduled basis. (Unlike Parameters, most Variables support the Set Value pick action and method, allowing the Variable’s value to be changed quite readily.)
- a value that does not require exporting to, or importing from, another ClearSCADA database. (Unlike Parameters, Variables are stored as data, rather than configuration, and as such are not included in .sde export or import files.)
Consider using an Array Variable, rather than a single-value Variable, if a series of values are required.
For more information on Variables and Variable arrays, see Using Variables to Store Data Values.
