Disabled tags - OPC Server limit impact

Hi folks,

Did my homework and went thorugh all related posts in the forum, but couldn’t find a specific answer to our specific -temporary- situation. Usual disclaimer, I’m just an average Ignition enthusiatic…who can’t easily take a “no” for an answer.

  1. We have to competing systems polling an OPC DA server for the same tags (we are migrating the old system to Ignition), which has a capacity limit of 20k tags.
  2. Each system is polling the same 12k tags, so in total we are polling 24k tags and that puts us above the server limit, generating random problems (missed data) in both systems sort of randomly.
  3. For business reasons -don’t ask :slight_smile: - we cannot simply shut down the older system yet. They have to coexist for a while.

QUESTION: If we temporarily disable a group of 4k tags in Ignition (uncheck the “Enable” attribute thorugh some script), will they still occupy tag capacity in the OPC Server? I understand the Tag Group will no consider disabled tags (and they shouldn’t add to the OPC Server count), but we are being told differently, that the only way to achieve that is to completely delete the tags in Ignition (we don’t want to do that).

Thanks and regards.

Who is telling you differently? I would expect that disabling a tag deletes the corresponding item from the OPC subscription.

1 Like

Thanks Kevin, now I can challenge with confidence! That’s what I would also expect; besides our particular issue at the moment, completely disabling -in all possible aspects- without deleting tags seems like a handy feature in many situations.

Let’s not put anyone on the spotlight, but it wasn’t just another Ignition enthusiastic :wink: