Experimental Physics and
Industrial Control System

Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov> · Mon, 16 May 2022 22:29:07 -0700

On 5/16/22 04:47, Nicklas Holmberg via Tech-talk wrote:

Hi,

I am using pva input links for two different records, a longin and a bi record. The “longin” record works without any problem, but the “bi” does not.

This is the expected behavior of QSRV as currently defined.
A biRecord (enumeration with two labels) isn't the same as
a PVA boolean type.  To map into bi or mbbi records, your
PVA server should provide an NTEnum.

The error shown in the IOC shell is:

pvaLink long int {anonymous}::pvaGetValue(DBLINK*, short int, void*, long int*) fails my-bi:pvapy-bool: castUnsafeV: Conversion not supported

which, of course, repeats every time the record is processed.

The PVs are served from a python pvapy application, and I have no problem reading them using general EPICS commands like pvget, pvinfo, etc. I use them as input links to the bi and longin records like this:

record(longin, "my-longin:pvapy-int"){

field(INP,      {pva:{

                 pv:"plc-ts:PLC:ts_1252_ns",

                 proc:"CPP"

           }})

}

record(bi, "my-bi:pvapy-bool"){

field(INP,      {pva:{

                 pv:"plc-ts:ptp:synchronized ",

                 proc:"CPP"

            }})

}

The IOC uses EPICS 7.0.6.1 and the following st.cmd:

#!/usr/bin/env iocsh.bash

dbLoadRecords("nsrecord.db")

iocInit()

Doing “pvinfo” on the incoming PVs show:

$ pvinfo plc-ts:ptp:synchronized

plc-ts:ptp:synchronized

Server: 10.102.10.19:5075

Type:

     epics:nt/NTScalar:1.0

         boolean value

         string descriptor

         structure alarm

             int severity

             int status

             string message

         structure timeStamp

             long secondsPastEpoch

             int nanoseconds

             int userTag

         structure display

             double limitLow

             double limitHigh

             string description

             string format

             string units

         structure control

             double limitLow

             double limitHigh

             double minStep

$ pvinfo plc-ts:PLC:ts_1252_ns

plc-ts:PLC:ts_1252_ns

Server: 10.102.10.19:5075

Type:

     epics:nt/NTScalar:1.0

         string value

         string descriptor

         structure alarm

             int severity

             int status

             string message

         structure timeStamp

             long secondsPastEpoch

             int nanoseconds

             int userTag

         structure display

             double limitLow

             double limitHigh

             string description

             string format

             string units

         structure control

             double limitLow

             double limitHigh

             double minStep

______________________

*Nicklas Holmberg*

Senior Engineer, ICS HWI

*European Spallation Source ERIC*

P.O. Box 176, SE-221 00 Lund, Sweden

Visiting address: Partikelgatan 2, 224 84 Lund

Mobile: +46 76 168 06 60

E-mail: nicklas.holmberg at ess.eu <mailto:nicklas.holmberg at ess.eu>__

ess.eu <ess.eu>__

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System