SANS2D: Use delayed moves for tank collision avoidance

[DominicOram]

As an IS on SANS2D I want to be sure that the hardware inside my tank doesn't collide with each other. Various methods have been tried in IBEX to do this (https://github.com/ISISComputingGroup/IBEX/issues/5894) but it was decided that we should instead do it the same way that SECI does:

• There are top-level PVs and a top level OPI for the tank
• Setting positions to these top level PVs use delayed moves
• The set PV can only be actioned if the move will not cause a collision

Acceptance Criteria

• [ ] The above is implemented
• [ ] The old way of doing collision avoidance on SANS2D is removed
• [ ] There are tests for this behaviour
• [ ] Blocks are added to these PVs
• [ ] Check if we need to take rotation into account

Notes

• Because this is a set of top-level PVs there will be no collision avoidance for moves made via the table of motors @RaiBishal to confirm with the scientists that this is ok (They are fine with it, asked Sarah on 20/09/2021)
• For the same reason blocks should not be added to the low level motors/axes

[DominicOram]

As part of removing the old code for collision avoidance we can remove https://github.com/ISISComputingGroup/EPICS-galil/blob/master/GalilSup/Db/galil_sans2d_front_det_limit_footer.dmc (also solving homing issues on S6)

[RaiBishal]

PRs: https://github.com/ISISComputingGroup/ibex_gui/pull/1358 https://github.com/ISISComputingGroup/EPICS-IOC_Test_Framework/pull/491/files https://github.com/ISISComputingGroup/EPICS-ioc/pull/639 https://github.com/ISISComputingGroup/EPICS-motorExtensions/pull/35 https://github.com/ISISComputingGroup/EPICS-upgrade/pull/61 (upgrade script) Config area to review: Ticket6785_delayed_move_SANS2D

RN: https://github.com/ISISComputingGroup/IBEX/pull/6807

[DominicOram]

Some comments on the PRs, additionally:

• Could you update https://github.com/ISISComputingGroup/ibex_developers_manual/wiki/SANS2D-vacuum-tank-collision-avoidance please?
• Have you thought about/discussed with SANS2D how this will work for scripting? It will mean that if they have a block on say baffle position just doing g.cset("Baffle_position") will not cause a move. They may need another hidden block on MOVE_ALL to actually do the move and then write to that in their scripts?

[RaiBishal]

Some comments on the PRs, additionally:

• Could you update https://github.com/ISISComputingGroup/ibex_developers_manual/wiki/SANS2D-vacuum-tank-collision-avoidance please?

I have updated it now.

• Have you thought about/discussed with SANS2D how this will work for scripting? It will mean that if they have a block on say baffle position just doing g.cset("Baffle_position") will not cause a move. They may need another hidden block on MOVE_ALL to actually do the move and then write to that in their scripts?

Yes I did ask SANS2D about it, they were happy to have a extra line in their script to do the actual move. This is what they did in SECI too.