HWP ACU checks for spin-up

[jlashner]

This PR adds a check of the ACU elevation before allowing for spinup of the HWP.

Description

Adds ACU state information to the HWPState class. This state info is used by the control-state update function to check the ACU elevation and last update time before enabling spin-up.

Motivation and Context

Motivation is described in Kyohei's discussion here: https://github.com/simonsobs/daq-discussions/discussions/96.

How Has This Been Tested?

This has not yet been tested! @ykyohei can we test this on one of the SATs? To test at a safe elevation, we can raise the acu_min_el param.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[ykyohei]

Thank you so much for doing this quickly. Yes, we can test this.

I have a question. Do you plan to implement the constraints between gripper and ACU by implementing it directly in the gripper agent? Or do you plan to add gripper control in the supervisor function?

[ykyohei]

el_commanded_position is monitored but not used for check_acu_ok_for_spinup.
I think we should check this too.

[jlashner]

@ykyohei My intention is to implement grip / ungrip procedures (or at least a wrapper for the gripper agent ops) in the supervisor, and to add the acu checks here. That will be the next PR.

[mhasself]

Just one more inline comment from me ...

And my outline comment is that you should probably add some discussion of this feature to the docs, or else make the docstrings and argument descriptions clearer. I can understand "Minimum elevation allowed before restricting spin-up" because I already know what this code is for... but I think there are clearer ways to say this. ("Elevation below which HWP spin-up is not permitted", for example)

[ykyohei]

I tested the acu_check in daq-dev and made small debugs. I believe it's working now.

[jlashner]

Great, thanks Kyohei!

I just implemented Matthew's suggestion for acquiring the last_updated timestamp from ACU session data, and also added a brief section to the docs on ACU safety checks that we can expand as we add the gripper operations and checks.

[mhasself]

Thanks for the additional clarifications.

[BrianJKoopman]

This seems ready to merge, but there are some merge conflicts in the agent code. Can you resolve these @jlashner?

[jlashner]

Looks like tests are failing due to this issue: simonsobs/ocs#391

Do we need to pin setup-tools in socs or upgrade the ocs version?

[BrianJKoopman]

Looks like tests are failing due to this issue: simonsobs/ocs#391

Do we need to pin setup-tools in socs or upgrade the ocs version?

I was thinking the later, but neither option is working...I might end up switching build systems, was trying to make that decision yesterday.