Hello, I've encountered an unexpected problem with using nHaystack v1.2.4 to sync histories between a Tridium AX and SkySpark.

The AX lost communication temporarily with the BAS network, and the history data on the AX have a status value of down during this time. However, the SkySpark points continued to sync the down history data through nHaystack, without any indication on the SkySpark side that the history was down. The SkySpark point's hisStatus value remains ok, although on the AX the history is down. I have screenshots that capture this behavior better than I can explain it in text.

Ideally, I'd like the SkySpark point either to not sync when the AX history is down or stale. Has this issue been addressed in a more recent version of nHaystack? If not, is there a way to configure nHaystack not to sync down history data?

Thanks, Jerry

I guess this would have to be a change on the nhaystack/AX side of things, rather than SkyFoundry, since there is no concept of the status of a history item in the hisRead op.

So I've added this to the to-do list as something we can try to add to the project in the future. In the mean time, you can try to figure out if there is some way to rig up AX to skip logging those values.

We've spent a lot of time thinking about this issue, and in SkySpark we are moving toward representing "bad values" with a new NA data type which is a concept from the statistical programming language R. I think it might be good to standardize that as part of Haystack too. Then for nHaystack the hisRead op can return NA for all values with a non-ok status value. But in the meantime, it might be best to just filter out any data that has a non-ok status value (by definition the value isn't trustworthy anyways).

Brian, Mike; Thanks for your feedback and getting this on the issue list for nHaystack. I'll see what we can do to filter out these values on the AX side.

Jerry