This lesson is part of the Transaction Groups in Ignition course. You can browse the rest of the lessons below.

Supplemental Videos


Learn how to use One-Shot execution on a Transaction Group while using either the Timer or Schedule option of the Execution Scheduling setting.

Video recorded using: Ignition 8.1


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[00:00] It is common to trigger a transaction group to execute on the rising edge of a Boolean value. For example, let's say I wanted this Boolean tag here to act as the trigger for the historical transaction group I have configured here. I could add this tag into the group by simply dragging it over like so. I can choose to either store my trigger value to the database, or I can make it Read Only by setting the target name to Read Only. The target name in this case translates to the table column where this tags value will be written to. Making it Read Only means my trigger will not be written to the database at all. On the trigger tab of my group, I can enable this group to execute on a trigger. I can use this dropdown to select my Boolean tag as my trigger item. I will then set my trigger condition to not equal to zero which means this group will execute if an only if my trigger item has a non-zero value.

[01:09] More importantly, however, I want to enable this setting here. Only execute once while the trigger is active. This means that the first time the group evaluates and sees the trigger value in a high state it will allow the group to execute once and it will not execute again until the trigger item goes from a low state to a high state again. If I save my group with this configuration we can now see that rows are only inserted each time the trigger tag transitions to true. Nothing happens until we toggle the trigger tag to false, and then back to true again. This is what is considered a rising edge trigger and allows you to trigger a group's execution only once based on a trigger condition.

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