I can’t figure out how to use the scan classes with MQTT (Tags).
I have a MQTT publisher the publishes the tags every 3 minutes (180000 ms).
Now in Ignition (7.9.10) I have just 4 tags set to store to a MSSQL database.
I can create a new scan class but when trying to setup the TAG to store to database and I goto
dropdown of the scan class my new scan class is NOT is the list.
I only have “Evaluate on Charge” and “Default Historical” scan class to select from?
All 4 tags are analog but - 1 tag only changes every 24 hours(daily).
I only need to store the daily tag a single record per day. The other 3 tags I need to store to database every 3 minutes.
Use a transaction group, there you can set the recording for every three minutes very easily. I’m not sure what scan class would have to do with you logging the tag in a db as long as it is a shorter duration than the transaction group timer. Are you trying to use tag history? I would recommend the transaction group over tag history if so.
If you want to make sure you have an entry every 3 minutes for the 3 tags and once a day for the other, I wouldn’t use the historian. You don’t gain anything by doing that. If you only need an entry when the value changes by a set point then historian would work. That is what the historical deadband is for. If you set that to 0 then your negating the historians ability to limit the number of entries you have. Personally I’d use a transaction group to store data in a table in your DB if you want to an entry at a set period, same as dkhayes117 already mentioned. Even if they are in a regular table, there is no reason you can’t trend them on an easy chart. You would just have to do a query to retrieve the data in the right format.
But as for not seeing the new scan class you created. If you can still see it as created when you go into your scan class editor, did you hit the refresh icon next to “Historical Scanclasses” in the history section of your tag?
Thanks for all the tips/information I will do more research on Transaction Groups. I will also double check on refreshing when I create new scan classes.