Experimental Physics and Industrial Control System
|
Hi Ben
thanks for the more detailed explanation.
In the doc, this example is given:
{calc: {expr:"A*B", args:[{db:"record.VAL"}, 1.5], prec:3}}
which uses the link type 'calc', which must be a valid link type according to the documentation. However, I receive the same error. Whenever I use anything author than 'pva'.
Also, if (and it doesn't sound that strange) "{db:"${SYS}:constFloatPi"}"
is as valid PV, so is "{pva:"${SYS}:constFloatPi"}",
which works perfectly fine.
Maybe it has change when this feature was introduced?
best
Niko
--
Paul Scherrer Institute
Dr. Niko Kivel
Forschungsstrasse 111
WBGB/017
5232 Villigen PSI
Switzerland
phone: +41 56 310 2226
email: niko.kivel at psi.ch
From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Ben Franksen via Tech-talk <tech-talk at aps.anl.gov>
Sent: Thursday, March 26, 2020 09:22
To: EPICS Tech Talk
Subject: Re: PV Access
Am 26.03.20 um 07:09 schrieb Ralph Lange via Tech-talk:
>> # not working: error --> dbJLinkInit: Link type 'db' not found
>>
>> record(ai, "${SYS}:dbInput") {
>>
>> field(INP, {db:"${SYS}:constFloatPi"})
>>
>> }
> The key is the second sentence in the documentation you refer to:
> The IOC continues to support the older link types that do not use JSON to
> specify their link addresses.
Hi Ralph,
I think your answer, while not exactly wrong, is a bit cryptic, so let
me explain.
The docs list the available link JSON types. There is no "db" link type
listed, which explains the error you get. What Ralph alluded to is the
reason /why/ there is no JSON "db" link type. This is because, strange
as it may sound, '{db:"${SYS}:constFloatPi"}' is actually a valid name
for a record and thus for a PV. A long, long time ago it was decided
that a PV name may contain any byte that is not reserved for a special
purpose by EPICS base (such as '.' and a few others), instead of a
priori limiting this set to something reasonable.
Cheers
Ben
________________________________
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
Mitglied der Hermann von Helmholtz-Gemeinschaft Deutscher Forschungszentren e.V.
Aufsichtsrat: Vorsitzender Dr. Volkmar Dietz, stv. Vorsitzende Dr. Jutta Koch-Unterseher
Geschäftsführung: Prof. Dr. Bernd Rech (Sprecher), Prof. Dr. Jan Lüning, Thomas Frederking
Sitz Berlin, AG Charlottenburg, 89 HRB 5583
Postadresse:
Hahn-Meitner-Platz 1
D-14109 Berlin
|
- Replies:
- Re: PV Access Ben Franksen via Tech-talk
- Re: PV Access Ralph Lange via Tech-talk
- References:
- PV Access Rolf Keitel via Tech-talk
- Re: PV Access Johnson, Andrew N. via Tech-talk
- Re: PV Access Kivel Niko (PSI) via Tech-talk
- Re: PV Access Ralph Lange via Tech-talk
- Re: PV Access Ben Franksen via Tech-talk
- Navigate by Date:
- Prev:
Re: PV Access Ben Franksen via Tech-talk
- Next:
Re: PV Access Ben Franksen via Tech-talk
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
<2020>
2021
2022
2023
2024
- Navigate by Thread:
- Prev:
Re: PV Access Ben Franksen via Tech-talk
- Next:
Re: PV Access Ben Franksen via Tech-talk
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
<2020>
2021
2022
2023
2024
|
ANJ, 26 Mar 2020 |
·
Home
·
News
·
About
·
Base
·
Modules
·
Extensions
·
Distributions
·
Download
·
·
Search
·
EPICS V4
·
IRMIS
·
Talk
·
Bugs
·
Documents
·
Links
·
Licensing
·
|