Recording History

Ignition has two main approaches to recording historical data:

• Tag Historian: Individual or groups of tags can be configured to record history based on scan class execution.

• Transaction groups: Groups of OPC items that are recorded on an execution cycle. More information on Transaction Groups can be found in the SQL Bridge (Transaction Groups) section.

Historian Charts

Creating charts to display historical data or realtime data is a snap! The Easy Chart component allows you to make powerful, runtime-configurable time series charts from the Tag Historian data. Simply drag and drop history-enable tags onto a chart a chart to create chart pens and data trends. Your charts and graphs can include subplots, axes, digital offsets, and a moving average pen. You can quickly and easily turn your historical and realtime data into dynamic charts and graphs for your users.

To see all the chart options and features, refer to the section on Using the Easy Chart.

Historian Tables

Just like charts, creating tables using the Table component is just as easy! Drag and drop historian enabled tags onto a table component to display historical values in many different ways depending on how you customize your table. You can bring back the most recent history, a specific date range, fixed sample size, interval sample size, and more. To see all the table options and features, refer to the section on Tag Historian and Tables.

Tag Historian Querying

While the data is stored openly in the database, the format does not lend itself well to direct querying. Instead, Ignition offers a range of built-in querying options that are very powerful and flexible. In addition to the simple on-change querying, the system can perform advanced functions such as querying many tags from multiple providers, calculating their quality, interpolating their values, and coordinating their timestamps to provide fixed resolution returns.

Querying can be performed on tables and charts through the Historical Binding, and through scripting. You can also query tags from the Reporting Module.

Other Methods of Storing Historical Data

SQL Bridge (Transaction Groups) perform a variety of tasks, one in particular, to store data historically. In their simplest form, transaction groups read values from the OPC addresses, and store them into a SQL database. There are four types of Transaction Groups; Standard, Block, Historical, and Stored Procedures. Each transaction group handles data a little differently.

• Standard Group - is the most flexible, and can also write database values to OPC addresses or synchronize data changes between both the database and PLC. This allows you to create true realtime values tables in a database, and push values to a PLC.

• Historical Group - can quickly store data from the plant floor into any kind of SQL database.

• Block Group - transfers large amounts of data very efficiently.

• Stored Procedures - uses PLC data as inputs and outputs from your existing stored procedures.