Figure 2.   Simplified history process

• Collecting data involves defining the properties that specify what data to record and how often to record it. For example, you can collect data whenever a change of value occurs - or at a regular time interval that you specify. To collect history information you need to:
  • Add history extensions to components.
  • Configure the extensions.
  • Use a valid history name (part of the configuration).
• Storing data involves defining the properties of the history database file. For example, you can customize the name of the database file, define the maximum number of records to save, and choose metadata to add to the records.
• Archiving data includes importing and exporting (transferring) records from one station to another station. For example, you can limit your local station records to a small number, which you specify while archiving all collected records to another station.

To extend the functionality of the component, you add extensions to a component’s Property Sheet. By adding a history extension, you can collect a time-stamped entry in the associated history table for a the real-time value or the status of the component’s output. The history palette makes history extensions available.

Figure 3.   History extensions in the history palette

The history table is not stored as part of the component’s data but is a separate collection of data referred to as the “history.”