Historical data

Historical data are data from earlier points in time that are stored in a database. Any server symbols of the TwinCAT HMI (e.g. numerical value from the PLC) can be historized using a Historize Extension. The extension saves the data in a ring memory in a database. The interval at which the data are saved in the database can be defined for each symbol. The data are saved in the database only as long as the server is running. No historical data are written to the database if the server is terminated.

The TwinCAT HMI has various extensions for recording historical data.

SQLite

Use the Historize Extension in connection with an SQLite database.

PostgreSQL

Use the Historize Extension in connection with a PostgreSQL database.

Controls

The historical data are displayed in an included control – the Trend Line Chart. The control enables the display of various historical data at the same time.