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What are Transaction Groups? They allow you to create simple bi-directional links between your PLCs and databases using Transaction Groups. With Transaction Groups you can perform tasks such as database to OPC synchronization, recipe management, and historical data logging.

Video recorded using: Ignition 7.9

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[00:00] Transaction groups are objects that map data in Ignition to and from a database. For example, they could be used to map data from tags to a row in a database table. They have a wide range of settings that affect how and when the synchronization takes place. Transaction groups are provided by the SQL Bridge Module. When the module's installed, you will see a new node in the designer under the product resource tree. When you create groups, they are part of the current project that you are editing. Groups are designed and modified in the designer, but execute on the gateway. Once started, groups run indefinitely. In the designer, we'll configure the groups as we like, saving them as we go. When we're ready to run the group, we can set it to enabled and save again. Then we'll begin to get status information coming back into the designer. At any time, we can come into the group and edit it as it runs. It's important to note that while we're editing, the previous configuration continues to run on the gateway. When we're happy with our configuration, we can save, and a new instance of our group replaces the previous one. However, if you're not happy with your executing group, you can choose to pause it while you modify it. There are several types of groups that accomplish different goals. All group types, however, follow a few common principles. Once started, they all execute on a timer. They contain data items, which can be from OPC, configured tags, or might be expressions or SQL queries. Items can be mapped one way, either to or from the database, or by directionally. This means that the database will be monitored and when data changes on one side or the other, it will automatically be written to the other side. They can use several different triggering mechanisms, which in conjunction with the timer, can specifically dictate when the group should actually execute. When the group is finished running, success or failure can be communicated back to other tags through the handshake mechanisms. The additional videos in this series will dive deeply into each of these features and provide examples of how they might be useful. In short though, the ability to map data to custom or existing tables to synchronize data one way or by directionally, flexible triggering, and the ability to modify groups with minimal downtime make transaction groups a key component to many Ignition projects.

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