SANS2D: Front Detector Beam Stop

[kjwoodsISIS]

As a SANS2D scientist, I want IBEX to provide control for the front beam stop, so that I can control its position.

Acceptance Criteria

1. If the detector rotation is greater than 0 degrees, motion of the front beam stop must be inhibited.
2. I can control the rotation of the front beam stop via the IBEX GUI.
3. I can control the rotation of the front beam stop via genie_python.
4. Beam stop motors are de-energised when motion is complete.

Notes

1. This ticket is a sub-ticket of SANS2D: Control of Vacuum Tank (EPIC) #4576.
2. The front beamstop must not be operated if the front detector is rotated.
3. Because the motors that move the beam stops operate in a vacuum, they should be de-energised when a move is complete (otherwise they are at risk of over-heating).
4. There are schematic diagrams showing the operation of the SANS2D vacuum tank.
5. There are schematic diagrams showing the how the SANS2D vacuum tank User OPI and Advanced OPI could look.
6. The LabVIEW VI for the SANS2D vacuum tank is located at: C:\LabVIEW Modules\Instruments\SANS2D\Sans2d Tank (for more details see the S2d Tank - Front Panel.vi in the file Sans2d Tank - System Functions.llb)
7. Check the paragraph describing the Front Detector Beamstop in the Beam_line_descriptors document.

[John-Holt-Tessella]

Inhibition:

• On rbv or sp change of detector angle do the following logic
• if rbv or sp > 0:
  • call, stop motor and DISP = True
• else set DISP=False

The DISP is on the axes record. We have not used the inhibtor because it does not react to change like this and this is a

[FreddieAkeroyd]

Would we need to set DISP on both the motor and axis for safety? DISP only disables channel access puts and not ones linked from within the IOC, if this is a potential concern would it be better to disable the motor record itself from scanning?

[John-Holt-Tessella]

Would that not stop the Stop button from working on the motor because it is a field

[JamesKingWork]

PRs:

• Ticket4581 front detector beam stop EPICS-ioc#515
• Basic beamstop ibex_gui#1146
• Ticket4581 front detector beam stop EPICS-motorExtensions#26
• Ticket4581 front detector beam stop EPICS-IOC_Test_Framework#350
• Front beamstop control and inhibited light ibex_gui#1160