Remove COM from DG645

[FreddieAkeroyd]

Description of work

I think COM is incorrect - seen error on EMU

[2025-03-06 10:43:52] INFO -- asynInterposeCOM options extending and perhaps overriding those of lower interface.
[2025-03-06 10:43:52] WARNING -- Can't set serial port parameters: Device says WON'T 0.

To test

Which ticket does this PR fix?

Acceptance criteria

List the acceptance criteria for the PR

---

Code Review

• A copy of the manual has been placed on the shared drive
• Pertitent information has been stored in the wiki
• Does the IOC conform to IBEX standards?
  • PV naming.
  • Disable records
  • Record simulation
  • Finishing touches
• If an OPI has been modified, does it conform to the style guidelines?
• Do the IOC and support module conform to the new build guidelines
• Have the changes been recorded appropriately in a PR for release notes?
• Is the device's flow control setting correct? For most devices flow control should be OFF.

Functional Tests

• IOC responds correctly in:
  • Devsim mode
  • Recsim mode
  • Real device, if available
• Supplementary IOCs (..._0n where n>1) run correctly
• Log files do not report undefined macros (serach for macLib: macro to find instances of macLib: macro [macro name] is undefined...

Final steps

• Update the IOC submodule in the main EPICS repo. See Git workflow page for details.
• Reviewer has merged the associated PR for the release notes

[rerpha]

do we need to test this on a device or have you done so by patching on an instrument?

[FreddieAkeroyd]

I haven't patched/tested but maybe we can/should, i was going on WARNING -- Can't set serial port parameters: Device says WON'T 0. which suggested it was not doing anything anyway and it was more on teh off chance if it caused any funny issues. So maybe we do it when they the multiple DG645 issue test at end of cycle unless we have a DG645 elsewhere?

[Tom-Willemsen]

will move to a shutdown task as I agree would like to test this on hardware before pressing merge

[esmith1729]

Talk with Steve Cottrell about testing with two DG645s on EMU for this as well