TrendMiner does not support changing the (interpolation) type of a tag in the data source. This implies that for example when you change a tag from linear to stepped interpolation in your historian the tag will not load anymore in TrendHub and an error will be shown. You will also notice that the tag index can no longer be updated and goes to a STALE state.

TrendMiner support can typically derive this from the logfiles, but if you already know this is the root cause of the problem then there are a few steps you can perform to resolve the issue.

• Refresh the tag cache manually in ConfigHub for the data source the tag is synced from (or wait up to 24h for the changes to be synced automatically)

• Restart the tm-compute service in ConfigHub or Edge Manager. Keep in mind that restarting tm-compute will entail downtime for the users (typically a few minutes).

• Re-index the tag.

• Edit and save all calculated tags which depend on the changed tag (it is not required to make any changes to the calculated tags). Calculated tags cache the interpolation type of their underlying tags. By resaving the calculated tags this cached type will be updated to the correct type. (Not resaving calculated tags might result in wrong search and monitoring results or errors when trying to load the tags.)

After performing these steps the changed tag should be able to load again in TrendHub.