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Any object in class 1/2/3 will also be in class 0. When class 1/2/3 items are first activated, they'll be initialized with a class 0 data integrity check poll, unless the option No “No class zero poll to initialize itemsitems” is checked in the Device tab.
There's also an option in the Device tab called Initialize “Initialize class 1-3 after comm failurefailure”. Since class 1/2/3 polls only return values for objects that have changed since the previous class 1/2/3 poll, if the class 1/2/3 items are invalidated after a communication failure, by default they won't become valid again until their values change in the device. Selecting this option will send a class 0 data integrity check poll to initialize the class 1/2/3 items after a communication failure, so that all class 1/2/3 items will become valid again immediately when communication is restored.
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The item DataIntegrityCheck sends a class 0 poll, and updates all items activated for the device with the data from that class 0 poll, regardless of what modifiers those items have. This item can be used to perform class 0 data integrity checks on a polling interval. To prevent data integrity checks from being performed by demand polls as well, check the option No “No data integrity check in demand pollpoll” on the Device tab.
Using Class 1/2/3 Items with Class 0 Items
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