Re: Linking a HIGH and LOW field to a PV

["Hu, Yong" <yhu@bnl.gov>]

The magic word "CP"  does magic thing (automatically getting updated value) only when it is used in a field whose type is INLINK (DBF_INLINK, input link), i.e. the field DOL of ao, INP of ai, etc.

See "5.12 Channel Access Links" at http://www.aps.anl.gov/epics/base/R3-14/12-docs/AppDevGuide/node6.html

The field type of LOW/HIGH of ao is DOUBLE. See https://wiki-ext.aps.anl.gov/epics/index.php/RRM_3-14_Analog_Output

And what is more: you should see error message during iocInit if you load your .db file just like you wrote below (... field(LOW, "$(P):SUBCRYO_SETP_MIN.VAL CP") ... ).

Yong HU

NSLS-II Controls Group

From: <tech-talk-bounces@aps.anl.gov> on behalf of "Dudley, David" <dudleyd@frib.msu.edu>
Date: Monday, November 21, 2016 at 11:30 AM
To: "tech-talk@aps.anl.gov" <tech-talk@aps.anl.gov>
Subject: RE: Linking a HIGH and LOW field to a PV

Wouldn’t a SEQuencer record be more appropriate for moving a bunch of values from one place  to another?

 

Later-

 

David Dudley Controls Engineer III Facility for Rare Isotope Beams Michigan State University 640 South Shaw Lane East Lansing, MI 48824-1321, USA Tel. 517-908-7133 Email: dudleyd@frib.msu.edu

 

 

From: tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Steiner, Mathias
Sent: Monday, November 21, 2016 9:13 AM
To: Bo Jakobsen <lister@f77.dk>; tech-talk@aps.anl.gov
Subject: RE: Linking a HIGH and LOW field to a PV

 

The brute force approach would be to use a calcout...

 

record(calcout, "$(P):SUBCRYO_SET_LOW") {

  field(INPA, "$(P):SUBCRYO_SETP_MIN.VAL CP")
  field(CALC, “A”)

  field(OUT , "$(P):SUBCRYO_SETP_S.LOW PP")
}

..and similar for .HIGH.

 

It’s the opposite of elegant but it’ll work.

 

cheers -mathias

 

 

From:tech-talk-bounces@aps.anl.gov [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of Bo Jakobsen
Sent: Monday, November 21, 2016 09:01
To: tech-talk@aps.anl.gov
Subject: Linking a HIGH and LOW field to a PV

 

Hi

I am trying to get "limits" to work on a "Soft Channel" record.
The challenge is that I have the limit values in another record, and want to make a link between the two records.

I would therefore like to something like this:

record(ao, "$(P):SUBCRYO_SETP_S") {
  field(DESC, "Huginn Sub-cryostat system setpoint")
  field(DTYP, "Soft Channel")
  field(VAL, "300")
  field(PREC, "3")
  field(EGU, "K")
  field(PINI, "YES")
  field(HSV, "MINOR")
  field(LSV, "MINOR")
  field(LOW, "$(P):SUBCRYO_SETP_MIN.VAL CP")
  field(HIGH, "$(P):SUBCRYO_SETP_MAX CP")
}


which, however, does not work.
It this possible, and in that case how.

Thanks in advance.
    Bo