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<== Date ==> <== Thread ==>

Subject: Re: Enable or select records
From: "Dr. Simon Friederich via Tech-talk" <tech-talk at aps.anl.gov>
To: Ralph Lange <ralph.lange at gmx.de>, EPICS Tech Talk <tech-talk at aps.anl.gov>
Date: Mon, 2 Jun 2025 13:59:03 +0200

Dear Ralph,

Thank you very much for the hints and explanation. I am currently trying to implement your advice.

I got rid of the calc record, the mbbi + Raw Soft Channel works nicely.

I've started with two types of modules and created the "Disable<type>" records.

#=============== bo Disable records ===============
record(bo, "$(P)$(R)slot$(SLOT):_disable_4chunit") {
    field(DESC, "Disable 4CH UNIT records")
    field(VAL,  "1") # disabled by default
    field(ZNAM, "enable")
    field(ONAM, "disable")
}
record(bo, "$(P)$(R)slot$(SLOT):_disable_output") {
    field(DESC, "Disable OUTPUT records")
    field(VAL,  "1")
    field(ZNAM, "enable")
    field(ONAM, "disable")
}

Unfortunately the SDIS="Disable<type> CA" does not work as expected or at least from what I see, all types are processed. Here an example

#===========================================
# Valid data (4CH UNIT, OUTPUT)
#=============== Read data valid ===========
record(bi, "$(P)$(R)slot$(SLOT):validdata_get") {
    field(DESC, "Read data is valid")
    field(INP, "$(P)$(R)slot$(SLOT):info_get.VAL[3] CP")
    field(ZNAM, "NO")   field(ZSV, "MAJOR")
    field(ONAM, "YES")  field(OSV, "NO_ALARM")
    field(DISV, "1") # Disable record if DISA=DISV
    field(SDIS, "$(P)$(R)slot$(SLOT):_disable_4chunit CA") # Sets DISA value
}

If I read the reference manual correctly it should work like this:
A not-empty SDIS-field sets the value for DISA and if DISA=DISV, then the record should be disabled, right?
Or the other way around: If DISA!=DISV, the record is enabled.

Although my bo records "_disable_4chunit" are set correct (the VAL fields are 0 for this modules and 1 else), the DISA is 1 for all my slots and hence all "validdata_get" are enabled.

What am I missing?

Best regards
Simon


Am 27.05.2025 um 09:24 schrieb Ralph Lange:
Hi Simon,

Without going into the specifics of your application...

Device type mapping:
No need for the calc - the mbbi can do the mapping itself. Use the "Raw Soft Channel" device support (in Base) to have the mbbi do RVAL-to-index mapping.

Disabling:
There are several ways, of course ... I would indeed use disabling.
Add one "Disable<type>" bo record to each per-device-type database, with a default setting of 1=disabled. Point all hardware-connected records of that device type to this Disable<type> using SDIS="Disable<type> CA". (CA option to avoid pulling all records into the same lock set.)

The missing link:
Connecting its SELL to your mapping mbbi, use e.g. a dfanout record with SELM=specified to write a 0 (=enabled) to the Disabled<type> record of the recognized card type. (Don't forget the PP flag to process the Disabled<type>.)

The whole thing is a template per slot that you instantiate for each slot that is used. (Or the max number of slots if you don't care about unconnected records.)

Cheers,
~Ralph

ps. Database links work only locally, Channel Access links work locally and remotely.
CP on input links means "set up a monitor and process me when the value changes" - which is perfectly legal in any case.


Replies:
Re: Enable or select records Ralph Lange via Tech-talk
References:
Enable or select records Dr. Simon Friederich via Tech-talk
Re: Enable or select records Ralph Lange via Tech-talk

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