Re: Some questions about CaLab (Dariush Hampai)

[Kathryn Baker - STFC UKRI via Tech-talk <tech-talk at aps.anl.gov>]

Hi Dariush,

I know I'm not Carsten, but I've used his software in LabVIEW. I'm not sure I understand what you are trying to achieve, so apologies if I over explain things, I'd rather ensure the fundamentals are clear in our minds so that we can communicate clearly.

As regards the array version of the VI, it is a different VI to the single one and is using an overloading pattern which means it looks the same, but isn't, whether you send it an array or a direct item. So the act of sending it an array is the same effect as doing one then then other.

The LabVIEW architecture will not be having any influence here as the programs are talking via channel access, which is one of the EPICS protocols, neither program knows about the other, they just have these tokens on a channel and they use those to do other things with them.

The above means that the IOC needs to be running to see anything. So for an array, the code to send it would actually make it two sends. using the example that Carsten gave it would send:

caput mm4006:m11.HOME 12

caput mm4006:m11.MOVN 24

I'm struggling to understand what you are trying to do with the second part, what is the workflow you have? From a quick look at the VI CaLab Info caches the data, as it isn't data to retrieve regularly in most use cases. Knowing what you are trying to achieve, not just the problem, will help people provide good information and answers.

Regards,

Kathryn

 

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Dariush Hampai via Tech-talk <tech-talk at aps.anl.gov>
Sent: 23 June 2025 10:11
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: Some questions about CaLab (Dariush Hampai)

 

Hi Carsten,
this means that if I send a CaLab get.vi with PV mm4006:m11 and the array field [HOMF,MOVN] I receive an array of value [12,24]... is it right?

The second question is more important... in someway even using disconnect all PV (or sending directly the names of PV to disconnect), with CaLab Info.vi I have in back all the PVs.
Is it possible that the problem is with the architecture of Labview? i.e., Labview64 or Labview32?

Awaiting your replay

Dariush

Il 23/06/2025 07:31, Carsten Winkler ha scritto:

The CA Lab does not have a function for writing multiple fields in a single channel access command.

Fields are written by adding the field name with a dot.

If you need to write to multiple fields, you can use array parameters as follows:

Carsten

Am 20.06.2025 um 21:02 schrieb tech-talk-request at aps.anl.gov:

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Message: 3
Date: Fri, 20 Jun 2025 17:27:15 +0200
From: Dariush Hampai <dariush.hampai at lnf.infn.it>
To: tech-talk at aps.anl.gov
Subject: Some questions about CaLab
Message-ID: <239527c2-f231-4cea-b327-d81f47d38a06 at lnf.infn.it>
Content-Type: text/plain; charset=UTF-8; format=flowed

Hi all,
I have some problems with CaLab, necessary to integrate epics with a 
LabView interface. In particular now I have two big problems:
1) i don't understand how to use multiple field in the same CA. For 
example, my newport IOC includes some records of the type
mm4006:m11.HOMF
mm4006:m11.MOVN
etc...
CaLab Put.vi does not include the field. What do I do? if I put (for 
example) mm4006:m11.HOMF and mm4006:m11.MOVN as PV I find two distinct 
PVs...
2) I am trying to generate a monitor of the various IOCs. When starting 
LabView there is no PV (via CaLab info.vi). If I start the IOCs I see 
the PVs. However if I stop the IOCs, via command prompt (caget etc...) I 
do not see (obviously) the active CA, while via CaLab info.vi the CA are 
still active and give me the last values read. Even after a reset of PV, 
using CaLab_Disconnect.vi, I still see the active CAs with the last 
value read. Where am I going wrong?

Dariush

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