Default Scan Class Edit


We had an issue a couple weeks ago where a SQL query tag was accidentally set to a scan class that didn’t exist, due to a typo. When this happens on a regular tag (not a UDT), Ignition will create a scan class for you (without any message popup) with a scan rate of 1,000 ms. We’ve confirmed this with support, although it seems like it was not 100% intentional design.

My question is, Is there any way to get into the install files/config and change the default scan class to be something like 10 or even 30 seconds to guard against this in the future? We had a catastrophic failure of our gateway and the system was down for over 24 hours as it was being rebuilt due to this.

I’ve already confirmed that simply changing the scan classed named ‘Default’ does nothing about the scan classes auto-created.



I’ve also had problems (errors) where tags were imported that used a scan class that didn’t exist.
There should be some kind of warning or error message to alert us to the problem so we can proactively correct missing scan classes when tags are saved or imported.

What does it name the new class? Could you browse through the tags on the system and have it warn you (via another tag that counts instances of auto-assigned tags) that it’s set them? Or it could even correct it to a default 30 second scan class?

I would be possible to make your own alert whenever a new scan class is made. I don’t think Ignition will let you programmatically edit it though.

There still should be a config file somewhere that has the default settings stored in it, but it might not be available to the administrator. It does sound like it could use some more alerts though at least. An alert would have let us fix the issue immediately instead of having the server run away from us with a cascading failure (took 2 hours before complete loss).

No you wouldn’t edit the new class, but you could change the scan class on the tag programmatically in response to the alarm. So if you had a pre-existing 30 second scan class and the alarm goes off for an auto-assigned scan class, you could have it programmatically change the scan class from the 1 second default one to the 30 second one you have set up.

In my case, I’ve made it a practice to import the Scan Classes before I import Tags.
It would be nice if the Scan Classes were exported with the Tags so that an import would include all of the Scan Classes used by the Tags being imported.
It would also be nice to have a “Where Used” or “Dependencies” view to be able to find all the tags that use a particular Scan Class.

You can do a couple of things to find tags from a particular scan class:
a) Add the scan class column and just look for them. or
b) Do a search within the tag browser for the scan class you want.

I had completely forgotten about adding columns to the Tag Browser. Thanks for the reminder.
I had never used the search before and it worked well.
I still would like to see a warning message if I import Tags that use a Scan Class that doesn’t exist on the gateway where I’m doing the import.
Another option would be to include Scan Classes in the Tag export and import .XML file.

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