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LESSON LIST
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2:56About Transaction Groups
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4:42Types of Groups
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2:48Group Update Rate
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3:17Item Types
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3:19Tag References vs. OPC Items
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2:58Expression Items
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4:03SQL Query Expression Items
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3:14Run Always vs. Triggered Items
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3:04Hour and Event Meters
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3:17Resetting Hour and Event Meters
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2:50Trigger – On Value Change
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2:21Trigger – While Condition is True
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1:42Trigger – Rising Edge (Once)
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2:12Trigger – Reset Trigger
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1:50Trigger – Handshakes
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LESSON
Trigger – While Condition is True
Description
Learn how to execute a group only while a trigger condition is true. This is most commonly accomplished on Boolean or Integer triggers, or on Execution Scheduling.
Video recorded using: Ignition 7.9
Transcript
(open in window)[00:00] Many times when we want to execute a group on a trigger, we want the group to run continuously while the trigger is active. Essentially this is the default triggering method in the group. If we take a tag suitable for triggering such as this Boolean, come over to the trigger tab and enable the trigger, the default settings would cause the group to run while this Boolean was true. We see that the trigger condition is greater than zero, which for Boolean means true. And without any of the other settings, the group would run continuously. Another example of this type of trigger would be to instead use an integer tag, and to run the group while the integer was in a certain range. So if we bring integer tag over, on the trigger tab, we can select that value. And then down in the free form condition section, we can specify when the group will be active or nonactive. So for example, we could say that the group will be active when greater than 50 and then inactive when less than or equal to 10. If we enable the group with these settings, we will not see any rows inserted unless the integer meets our conditions. If we go to 65, the group will begin logging and will continue until we go below 10. Till this value can float down and it will not affect the logging until we get down to a value outside of our range. Using this mode, it is easy to capture data while other conditions are true. For example, you may choose to only record values while a machine is running. In that case, you would have the group trigger off of Run bit. Or, as another example, a numeric range like that just shown, could be used to capture abnormal events. For example, you could capture groups of related data whenever a temperature was outside of a certain tolerance.