Experimental Physics and
Industrial Control System

Hello,

I’m trying to instantiate a NTNDArray with some NTAttributes in my IOC using QSRV group PV definitions, as the example in pva2pva (https://github.com/epics-base/pva2pva/blob/master/iocBoot/iocimagedemo/image.db ).

If I set the database as the following:

record(waveform, "$(P)ArrayData") {

    field(FTVL, "USHORT")

    field(NELM, "262144")

    info(Q:group, {

        "$(N):Array":{

            +id:"epics:nt/NTNDArray:1.0",

            "value":{+type:"any",

                     +channel:"VAL",

                     +trigger:"*"},

            "":{+type:"meta", +channel:"SEVR"}

        }

    })

}

record(mbbi, "$(P)FOO") {

    info(Q:group, {

        "$(N):Array":{

            "attribute[0].value":{+type:"any", +channel:"VAL"},

            "attribute[0].timeStamp":{+type:"meta", +channel:"TIME"}

        }

    })

}

the resulting NTNDArray PV will have the following structure in its attribute[0] field:

structure

            structure timeStamp

                alarm_t alarm

                    int severity 0

                    int status 0

                    string message NO_ALARM

                time_t timeStamp

                    long secondsPastEpoch 1667394506

                    int nanoseconds 335496073

                    int userTag 0

            any value

                double  0

The timeStamp values of the top structure are correctly taken from the “ArrayData” record. However, for the “attribute[0]” field, the timestamp values are taken from the “FOO” record, but the structure of the NTAttribute contains two other structures (alarm and timeStamp) inside the “top” timeStamp structure.

The question is: how one can set the “timeStamp” structure of the attribute[] taking the TIME information from a different record than the one used to get the array value?

Thanks in advance!

João Paulo Martins

European Spallation Source ERIC