Experimental Physics and
Industrial Control System

Hello Érico.

 

Thank you so much. Now I'm starting to grasp the philosophy and workings behind the EPICS Modules. I have already managed to compile the RecCaster with QSRV in order to work with pvAccess. Now, I will start to compile the EPICS Device Support for OPC UA with QSRV.

 

Cheers and Happy Christmas,

Eusebio.



El 2023-12-20 15:04, Érico Nogueira Rolim escribió:

Hi Eusebio,

On 20/12/2023 10:44, Eusebio Naif Al-Soliman Fuentes via Tech-talk
wrote:

Hello Ralph.

Sorry, I don't see the binary distribution in the 'Assets' folder of
the releases in GitHub
(https://github.com/epics-modules/opcua/releases [1]), all the
releases need to be compiled, apparently.

IOC_opcua-0.9.4_Base-${BASE_VERSION}_${DISTRO}.tar.gz files are binary
releases.

If I define the EPICS_BASE = /path/to/my/EPICS/Base/install inside
the configure/RELEASE file of the EPICS Module, and I compile with
'make', I obtain a binary file inside bin/linux-x86_64/

However, I have found that the binaries that I obtain with the
compilation of RecCaster and the OPC UA Module work only with
Channel Access and not pvAccess. That's why I'm trying to "compile"
or "use" in some way the "softIocPVA" binary. What should I have to
do to in order to use pvAccess in that case?

You would create your own IOC, as explained in [1], which links to the
two modules you want to use, RecCaster and OPC UA.

Then, in your App's src/Makefile, you would add the DBD and LIBS line
documented in the "Adding QSRV to your IOC" section in [2]. This will
make it so your PVs are available over PVA.

[1]
https://docs.epics-controls.org/en/latest/getting-started/creating-ioc.html
[2] [2] https://epics-base.github.io/pva2pva/ [3]

Also, I still don't know how to run at the same time two or more
modules, for example, the RecCaster and the OPC UA module with the
same PV like 'temperature:water'. In summary, what I want to do is
to use at the same time the ChannelFinder service and the OPC UA
Device Support for the same PVs (from an IOC db). Additionally
better if we can use PVA.

I think you misunderstood how these modules interact with records. OPC
UA is a device support module, which connects your records to a given
device; this is the one you can only have one of per record.
RecCaster, when built into an IOC, provides a list of all available
records on that IOC, without requiring any sort of configuration in
your record (it is not a device support support).

Sorry for being so annoying, I'm having big issues understanding how
the EPICS Support Modules are used.

Thanks Eusebio.

---
Saludos/Best regards

University of Granada  

Eusebio Naif Al-Soliman Fuentes
MSc. Data Science and Computer Engineering

eunaif at correo.ugr.es

El 2023-12-20 10:12, Ralph Lange escribió: Hi Eusebio,

On Wed, 20 Dec 2023 at 08:53, Eusebio Naif Al-Soliman Fuentes <
eunaif at correo.ugr.es> wrote:

In that case, I understand that I have to use the binaries of the
EPICS
Support Module instead of the ones from EPICS Base.

I'm not sure I understand what you mean.

If you are referring to the OPC UA Device Support, you can use the
binary
distribution if you don't want to or can't compile the low-level
client
library. When you use the binary distribution, you don't need to
download/compile the Device Support module nor the low-level client
library, as both are part of the binary distribution.

However, what happens if I want to use, with the same PVs, EPICS
Base and the EPICS Support Module? Or, for instance, two different
EPICS Modules
with the same PVs?

That question does not really make sense.

EPICS Base contains some libraries and configuration files.
Additional
EPICS support modules contain more libraries and configuration
files.
To create an IOC that uses things from support modules, you need
both EPICS
Base and the support modules. The IOC binary needs to be linked
against the
libraries from the support modules and EPICS Base. Configuration
files from
the support modules and EPICS Base are used to create the
configuration
files for the IOC.

EPICS relies on PV names to be unique in the system. Running
multiple IOCs
with the same PVs is an error. Clients will connect to one or
another
quasi-randomly and spit out error messages.

I've to use a RELEASE.local file, but what do I have to write on it
and in which location should reside in order to use EPICS Base and
the modules
together?

Any EPICS build (when you run "make" inside an EPICS module) will
look for
RELEASE.local files in different places, including in the directory
above
its TOP and inside the TOP/configure directory.
If you don't want to repeat the configuration inside every support
module,
putting a single file one level above the modules is read by all of
them.

RELEASE and RELEASE.local files contain (that's documented) the
locations
of all support modules as multiple lines of the form
MODULE_NAME = /absolute/path/to/the/module
with the EPICS_BASE definition usually last.

Cheers,
~Ralph

Aviso Legal: Esta mensagem e seus anexos podem conter informações
confidenciais e/ou de uso restrito. Observe atentamente seu conteúdo
e considere eventual consulta ao remetente antes de copiá-la,
divulgá-la ou distribuí-la. Se você recebeu esta mensagem por
engano, por favor avise o remetente e apague-a imediatamente.

Disclaimer: This email and its attachments may contain confidential
and/or privileged information. Observe its content carefully and
consider possible querying to the sender before copying, disclosing or
distributing it. If you have received this email by mistake, please
notify the sender and delete it immediately.

Links:
------
[1] https://urldefense.com/v3/__https://github.com/epics-modules/opcua/releases__;!!D9dNQwwGXtA!QI32nlQl0XrheiQoUIZYKzzrJ8LN4SLRuo6elZLkLd5a50XuHMTuAgDyPN9BLFq-wZv57pX8GY4V-5bxL0lDLWSM$
[2] https://urldefense.com/v3/__https://docs.epics-controls.org/en/latest/getting-started/creating-ioc.html__;!!D9dNQwwGXtA!QI32nlQl0XrheiQoUIZYKzzrJ8LN4SLRuo6elZLkLd5a50XuHMTuAgDyPN9BLFq-wZv57pX8GY4V-5bxL6Ypevrn$
[3] https://urldefense.com/v3/__https://epics-base.github.io/pva2pva/__;!!D9dNQwwGXtA!QI32nlQl0XrheiQoUIZYKzzrJ8LN4SLRuo6elZLkLd5a50XuHMTuAgDyPN9BLFq-wZv57pX8GY4V-5bxL31aXjr0$