Cautions

Caution BC Cautions targeting 2-BM Assets and Procedures.

Operator tribal knowledge captured at shakedown, first-light, or production time. Surfaced on every future Run start via the CautionLookup snapshot. See Model for the aggregate shape.

Target	Category	Severity	Text
Aerotech_ABRS_rotary	Wear	Caution	Misses index pulse on cold-start home; retry after 5s
Hexapod_2BM	Wear	Caution	Locks up under sustained load; recover via hexapod_reboot

Aerotech cold-start index miss

Wear / Caution. Tags: aerotech, home, cold_start.

Observation. The Aerotech ABRS rotary stage misses its index pulse on the first home attempt after a power cycle. Subsequent homes work; only the cold-start first attempt is affected. Observed during 2-BM shakedown on 2026-05-17.

Workaround. Issue HOME command, wait 5s for settling, re-issue HOME. Verify index_pulse=1 on encoder readback before treating home as successful. Optionally pre-warm the stage by jogging +/-1° before the first home.

Lifetime. No expires_at (permanent until superseded or retired). Persists on the operator banner for every future Run start at 2-BM until the underlying stage is replaced or recalibrated.

Hexapod controller lockup

Wear / Caution. Tags: hexapod, controller_lockup, pdu_power_cycle, ioc_restart.

Observation. The PI-Hexapod sample-positioning controller occasionally locks up under sustained load: the 2bmHXP:HexapodAllEnabled EPICS PV reads 0 while motion commands return no error. Operator-observable symptom is the hexapod stops responding to position requests even though no fault has been raised by the motion-control layer.

Workaround. Run hexapod_reboot.py (in 2bmb-bin): stops the hexapod IOC, power-cycles PDU outlet 4 with 10s settling each way, restarts the IOC, polls HexapodAllEnabled for up to 180s. If the PV is still 0 after the timeout, caput 2bmHXP:EnableWork.PROC 1 to force-enable, then re-poll. Manual checks during recovery: verify outlet state via NetBooter /status.xml; SSH 2bmb@arcturus for IOC log inspection.

Lifetime. No expires_at (permanent until superseded or retired). Surfaces on every future Run start at 2-BM that targets the Hexapod, so operators know to run the recovery routine on first sign of unresponsiveness rather than chasing a phantom motion-control bug.

Pending

Target	Category	Severity	Text
2-BM Unit			Vibration threshold exceeded after air-handler shutdown
Oryx_5MP_camera			Detector dark-frame drift after long beam-off periods
Scintillator_LuAG			Scintillator browning under prolonged white-beam exposure
Sample-stage Devices			Sample-stage backlash after manual handling