Experimental Physics and
Industrial Control System

Hi,

Thanks! But what EPICS record type should I then use to read a PVA Boolean type, like the "plc-ts:ptp:synchronized" PV described below? My end goal is to have a PV served from my IOC, which can be picked up by the Archiver service.

Best regards,

Nicklas Holmberg
Senior Engineer
Hardware and Integration Group
ICS Division
+46761680660

-----Original Message-----
From: Michael Davidsaver <mdavidsaver at gmail.com> 
Sent: den 17 maj 2022 07:29
To: Nicklas Holmberg <nicklas.holmberg at ess.eu>
Cc: tech-talk at aps.anl.gov
Subject: Re: Conversion error when using (pvapy served) PVA input link in a "bi" record

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>__
> 

References:

Conversion error when using (pvapy served) PVA input link in a "bi" record Nicklas Holmberg via Tech-talk

Re: Conversion error when using (pvapy served) PVA input link in a "bi" record Michael Davidsaver via Tech-talk

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