Move flag into beam (mode-dependent)

Warning

STATUS: STUB. Placeholder for the procedure that satisfies the precondition flag_in_beam of Detector Z-rail alignment to the beam (detector_z_rail_alignment). The flag is now in the Beamline components inventory (as 2bma:m44); the procedure that orchestrates it is what’s still TBD.

Name

set_flag_in

Source

Not yet implemented. Future location: procedures/set_flag_in.py in the 2bm-procedures repository.

Devices

Beamline components: Flag (diagnostic phosphor) — single vertical (Y) motor 2bma:m44. User/dial offset: user = dial - 5 mm. User-coord limits: -4.5 to +35.0 mm.

Preconditions

Enable beamline for beam (enable_beamline).
For mono mode: Set energy to preselect (set_energy_to_preselect) — the target flag Y depends on the current DMM energy via the energy_move_flag lookup in energy2bm.json.

Parameters

mode (enum: pink | mono) — beamline mode. Default: derived from current DMM state (out = pink, in = mono).
flag_y_mm (number, user coord) — explicit target Y. If not given, derive from mode:
- pink: flag_y_mm = 0 (lower position, out of beam).
- mono: flag_y_mm = energy_move_flag[current_energy_keV] (read from energy2bm.json). Indicative values: 13.374 keV → 23 mm, 18 keV → 17 mm, 20 keV → 15 mm, 25 keV → 12 mm, 30+ keV → 0 mm.

Steps

Determine target Y from mode + (if mono) energy lookup.
Range check: -4.5 ≤ flag_y_mm ≤ 35.0.
move_motor 2bma:m44 <flag_y_mm>; wait for DMOV.

Postconditions

Satisfies:: flag_in_beam
Predicate:: 2bma:m44.RBV within motor tolerance of the commanded flag_y_mm.

Failure modes

Motor fault on 2bma:m44 — check the motor record’s status and clear before retrying.
For mono mode: energy2bm.json has no entry for the current DMM energy — operator must either calibrate the lookup or pass flag_y_mm explicitly.
Range check fails — typically operator misread mm vs encoded units; verify against the meters_all.adl MEDM screen.

Notes

In detector_z_rail_alignment (v0.0.1) the procedure assumes the flag is already in the appropriate position for the running mode. If pink-beam alignment is being done, the operator should have driven 2bma:m44 to 0 mm beforehand. The set_flag_in procedure formalises that step so cora’s dependency graph can resolve it.