Experimental Physics and
Industrial Control System

Kevin Peterson via Tech-talk <tech-talk at aps.anl.gov> · Tue, 28 Nov 2023 09:50:11 -0600

I wrote some general support (database + sequence program) to allow

things to happen after a delay:

  https://github.com/epics-modules/std/blob/master/docs/delayDo.md

It wasn't designed for this duty-cycle application, but two instances of

delayDo (one for enabling and one for disabling) are likely to provide

the needed functionality.

Kevin

On 11/22/23 03:07, Ralph Lange via Tech-talk wrote:

On Wed, 22 Nov 2023 at 09:43, Gerrit Kühn via Tech-talk

<tech-talk at aps.anl.gov <mailto:tech-talk at aps.anl.gov>> wrote:

    Instead, I'd like to send an "enable" command, have the device
    running for
    a configurable time (like 5min), then send a "disable" command and wait
    for a longer time (like 55min) until the next cycle is started.

As so often, the best solution depends on your requirements.

- Simple: seq record that fires links with delay. A single record could

do the job, but once it runs, you have zero control and zero visibility.

- Flexible: sequencer state machine. Define the interface you need

(control and monitoring) then implement the business logic in SNL. Yet

another tool and workflow. Any change needs recompilation.

- Transparent: use a few calcout records that basically count down,

initiating actions on "change to zero". More records for the interface

as needed.

I would probably go for the database solution, because of the full

transparency and online modifiable functionality (good when developing).

Also, counters are good for displaying progress bars on the GUI.

But that's clearly personal preference. I know colleagues that would

without hesitation use a sequencer state machine or a client-side Python

script.

In case you eventually have a generic database solution, please consider

posting it to https://github.com/epics-docs/database-examples

<https://github.com/epics-docs/database-examples>, which is a good place

to share such patterns.

Cheers,
~Ralph

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System