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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | Re: add fields to an existing record |
| From: | Mark Rivers via Tech-talk <tech-talk at aps.anl.gov> |
| To: | "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>, "Wolfman, Mark" <wolfman at anl.gov> |
| Cc: | "Delgado, Uriel" <udelgado at anl.gov> |
| Date: | Sun, 18 Jun 2023 15:07:27 +0000 |
|
Hi Mark,
Since this new field is intended for use by a single CA client (Ophyd for Bluesky) I think it is a better idea to use additional records and modify Ophyd to handle them. Then all changes can be external to the MCA module, and Bluesky does not need to depend
on a new release of the MCA module.
Note that your gitlab link is not accessible to those of us who are not APS employees.
Mark
From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Wolfman, Mark via Tech-talk <tech-talk at aps.anl.gov>
Sent: Monday, June 12, 2023 11:25 AM To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov> Cc: Delgado, Uriel <udelgado at anl.gov> Subject: add fields to an existing record Hi, tech-talkers.
Apologies in advance if parts of this don't make sense, I'm not that familiar with EPICS yet. I'm hoping to add a new region-of-interest field [1] to the MCA records used in an existing IOC for our DXP fluorescence detector. Similar to the other ROI fields, I'd like to have ``20bmxmap4b:mca1.R0BH``. This will be a 'bi' field that doesn't do anything in the IOC, but is used by bluesky/ophyd during staging to determine whether the specific ROI is hinted in bluesky (hence BH for "bluesky hint") [2] and is included in the calculations for summing ROI's across elements. I've added extra records to an IOC before, and so I tried adding this as a record but EPICS complained because my record name included a '.' character. One solution is to add a record like "20bmxmap4b:mca1_R0BH", but this makes the Ophyd part more complicated since the Ophyd MCA support expects the ROI to have a ``.Rn`` prefix and then tries to append the ``BH`` on the end[3]. Adding a record like ``mca1_R0BH`` means I have to re-write the MCA support in ophyd so I'd prefer to use the ``mca1.RnBH`` PVs if I can. The full IOC is available on gitlab, though it's presently a work in progress. Looking forward to hearing any ideas on how to make this work. Thanks, Mark [1] https://epics-modules.github.io/mca/mcaRecord.html#Region-Of-Interest_Fields [2] https://blueskyproject.io/ophyd/user_v1/reference/signals.html#kind [3] https://github.com/bluesky/ophyd/blob/0802c77ec973b0ba9f8554d3bcf3a3001def7f66/ophyd/mca.py#L14 [4] https://git.aps.anl.gov/20BM/20bmdxp/-/tree/main/ |