timestamps from control system (eg. Tango or EPICS)

[sona-patel]

Hello,
When we read any parameter from a control system (eg. Tango or EPICS) it always has a timestamp telling us when this parameter was processed/read. This is irrespective of whether this parameter is a static parameter (for eg. detector_number in NXdetector) or a new value (for eg. time_of_flight in NXdetector). We want to collect these timestamps in NeXus for debugging in case of some problem at the beamline. Would you suggest a place for these in NeXus?

Thank you :-)
Bluesky team of HZB

[rayosborn]

Parameters that are measured asynchronously during an experiment are normally stored in a NXlog group. There is a discussion of such use here. However, if you just store a single parameter as a scalar value, it would be possible to add an attribute to the field called 'timestamp'. Since it is impossible to specify the units of an attribute, it would have to be a ISO8601 string. There is an example of such use in the NXcanSAS application definition, although it is a group attribute in this example. I think the NIAC should consider adding documentation to formally approve this kind of use case.