Re: Probe plug-in for the Probe panel?

["Kasemir, Kay via Tech-talk" <tech-talk at aps.anl.gov>]

> display for custom CA record types

Not sure what that means.

CA/Channel Access and record types are fundamentally different.

EPICS was on purpose designed to separate them.

Channels and their properties, no matter if Channel Access or PV Access, are separate from records and their fields.

In fact you can have a CA or PVA server, i.e. channels on the network, without any IOC and thus no records at all.

See https://controlssoftware.sns.ornl.gov/training/2022_USPAS/ "10a CA vs Records vs CAS" for more.

For example, there is no "power supply" record. You'll instead have an analog output record to set the voltage, an analog input record to read the current, a binary output to turn the PS on/off, ... and then create a display that shows those values the way you like to present them.

Something like probe etc. is just a channel access or PV access client. It sees a value with units, it can display that no matter if it's the voltage setpoint, the current readback, the on/off switch. No client will automatically figure out that there's a power supply behind this.

If we kept adding new record types like a Power Supply record, each with their own new data type, then we'd also have to keep updating all the clients to learn about the new data types. So EPICS has basic analog and binary data types for the channels, and you then create a display in edm, medm, CS-Studio, PyQtDm, ... as you see fit.

-Kay

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From: William F Badgett Jr <badgett at fnal.gov>
Sent: Tuesday, April 4, 2023 3:50 PM
To: Michael Davidsaver <mdavidsaver at gmail.com>
Cc: Kasemir, Kay <kasemirk at ornl.gov>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: [EXTERNAL] Re: Probe plug-in for the Probe panel?

 

OK, that's a bit disappointing about the Probe.

But customizing PV Table and PV Tree would be useful to do, too.  Where would that start?

thanks

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From: Michael Davidsaver <mdavidsaver at gmail.com>
Sent: Tuesday, April 4, 2023 2:28 PM
To: William F Badgett Jr <badgett at fnal.gov>
Cc: Kasemir, Kay <kasemirk at ornl.gov>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: Probe plug-in for the Probe panel?

 

On 4/3/23 14:35, William F Badgett Jr via Tech-talk wrote:
> Hello Kay (or anyone who knows),
>
> Could you please advise on how to customize the Probe panels metadata display for custom CA record types?  Where to start?  (And eventually custom PVAs)

Do you mean "PV Tree" instead of "Probe"?

By design, Probe has no knowledge of any database record type (as in ao, longin, waveform, ...)
and only deals in protocol meta-data.

Unless you mean something else by "CA record types"?