Re: [EXTERNAL] Does every DB record need to produce a PV?

["Johnson, Andrew N. via Tech-talk" <tech-talk at aps.anl.gov>]

Hi Andrei,

I suspect that you only see this device’s internal PV names because you're running the recsync module’s RecCaster or its equivalent on the IOC, making all of its PVs visible through the Channel Finder. The device documentation probably doesn’t list or describe the internal PVs because the supplier didn't intend them to be accessed by users.

Do other sites using the Channel Finder have similar issues with internal PVs being included in its PV name database and making it harder to identify the public ones? Do you filter out the internal PVs at all?

We have Channel Finder installed at APS, but I suspect only a few people use it. Our naming convention allows us to mark internal PV names as such, but I don’t know if we filter those out of the CF database, and we do have commercial IOCs that don’t follow that convention. The PV name files that our IOCs generate (we don’t use recsync) are searchable, but only with some expert-level command-line programs or directly using grep, so our non-expert users normally only see the PV names on their GUI display widgets.

- Andrew

-- 

Complexity comes for free, Simplicity you have to work for.

On 2/17/26, 1:19 PM, "Andrei Sukhanov" <sukhanov at bnl.gov> wrote:

From my perspective, an EPICS IOC with ~2000 PVs lacking descriptions, for a device without a Programmer’s Manual, is unmanageable.

---

From: Hartman, Steven <hartmansm at ornl.gov>
Sent: Tuesday, February 17, 2026 12:58 PM
To: Sukhanov, Andrei <sukhanov at bnl.gov>; David Bracey <dbracey at fnal.gov>
Cc: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: [EXTERNAL] Does every DB record need to produce a PV?

 

This Message Is From an External Sender

This message came from outside your organization.

 

What makes you think this is unmanageable? There are plenty of counter examples of existing facilities where this works.

-- 

Steven Hartman

hartmansm at ornl.gov

On Feb 17, 2026, at 12:12 PM, Sukhanov, Andrei via Tech-talk <tech-talk at aps.anl.gov> wrote:

This Message Is From an External Sender

This email was sent from a non-ORNL address. If suspicious, use the Report Phish button in Outlook.

Mark, Kai,
The multitude of the PVs, not related to real device parameters, may pose real trouble for end users. For example, we were provided with an EPICS-driven PSC (power supply controller). The controller itself has ~200 of control parameters. But the IOC hosts ~2000 of PVS. This is just not manageable without tight support from original designers.

/Andrey Sukhanov,

Collider-Accelerator Department, BNL.

---

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>
Sent: Tuesday, February 17, 2026 11:54 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>; David Bracey <dbracey at fnal.gov>
Subject: Re: Does every DB record need to produce a PV?

 

This Message Is From an External Sender 

This message came from outside your organization. 

Hi Dave,

• A naïve user of EPICS would think that every database record of every IOC gets exposed as a PV.

Note that there is not a 1:1 relationship between records and PVs.  Even simple records like "bi" expose many record fields as PVs, not just the .VAL field.  For example, the .SCAN, .ZNAM, .ONAM, .SDIS, .DESC, and many more.  More complex records like the "motor" record have dozens of PVs, like .VELO, .ACCL, .STOP, .DVAL, .RVAL, etc.

Mark

---

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of David Bracey via Tech-talk <tech-talk at aps.anl.gov>
Sent: Monday, February 16, 2026 10:15 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Does every DB record need to produce a PV?

 

A naïve user of EPICS would think that every database record of every IOC gets exposed as a PV.

 

Is this truly the case?  If so, has any mechanism for hiding the “internal” records ever been discussed?

 

The PV-space of an EPICS deployment seems very crowded.

 

Dave Bracey

AD Controls

Fermi National Accelerator Laboratory