Re: PVA custom structs

[Sky Brewer via Tech-talk <tech-talk at aps.anl.gov>]

Hi, 

Looks like null/empty alarm data is acceptable: https://github.com/archiver-appliance/epicsarchiverap/blob/5045ec3939532bff67a10fbd59d76d9545375841/src/main/org/epics/archiverappliance/data/DBRAlarm.java#L6 

Error results are not awesome for the archiver appliance, but they are there. The reports pages covers a lot of the information needed for figuring out why a PV is not archiving.

I have an idea of improving workflows with the archiver, but it is a big refactor that is pretty low down in my priorities right now.

Hope that helps.

Sent from Outlook for Mac

From: Sky Brewer <sky.brewer at ess.eu>
Date: Tuesday, 12 May 2026 at 11:23
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>; junkes at fhi-berlin.mpg.de <junkes at fhi-berlin.mpg.de>
Cc: Ralph Lange <ralph.lange at gmx.de>; Michael Davidsaver <mdavidsaver at gmail.com>; Shankar, Murali <mshankar at slac.stanford.edu>; Timo Korhonen <Timo.Korhonen at ess.eu>
Subject: Re: PVA custom structs

Hi Heinz,

As other have mentioned for custom structs the Archiver expects:

NTScalar

where the value field is a structure. In particular timeStamp structure (including userTag) and alarms structure.  This is probably not well documented...

Maybe this is a type to add to the normative types documentation? NTStructure? Which actually could supersum NTScalar, NTScalarArray, NTEnum?

Note to retrieve the json api does unpack the data and return a sort of standard json output. I would like to upstream that from the Archiver Appliance to core-pva.

Hope that helps,

Sky