ZFront and ZCal operations and commands

Scope: beam routing, calibration injection, and calibration sources. Items share physical space but do not necessarily share a controller or software owner.

Diagram: ZFront D2. Connections: ZFront harness. Related operations: digital functions and calibration and acquisition procedures.

Beam routing

Function	Positions and optical path	Status and feedback
Neighbor/instrument selection	Left, right, ZShooter	Requested route; actuator position/state; intermediate, unknown, or active route
ZImage/ZSpec selection	Full imager field, or central spectrograph field with the remaining field to the imager	Requested route; actuator position/state; active route
Calibration insertion	Upstream of ZI/ZS selection and compatible with adjacent-instrument operation	Inserted/retracted/unknown; actuator position/state

Motion capabilities

Capability	Inputs	Status and feedback	Details still needed
Select neighbor or ZShooter path	Left, right, zshooter, engineering value	Requested and sensed position	Final route names, actuator, exposure overlap, sensor states and conflicting readings
Select ZImage/ZSpec configuration	zspec, zimage, engineering value	Requested and sensed position	Final route names, actuator, exposure overlap, sensor states and conflicting readings
Insert/retract calibration beam feed	in, out, engineering value	Requested and sensed position	Actuator, exposure overlap, sensor states and conflicting readings
Select point or extended illumination	Illumination mode	Requested and sensed position	Actuator, exposure overlap, sensor states and conflicting readings
Inspect or establish reference position	Mechanism	Whether position is known and how it is known	Reference method
Halt a move	Mechanism, if needed	Stationary state	Mid-travel state and impact on other axes

Command latency, travel, settling, and optical readiness will need separate timing values as the mechanisms are selected.

Illumination capabilities

Setting a source’s brightness selects and enables that source. A brightness of 0 or off turns it off.

Capability	Inputs	Status and feedback	Details still needed
Set brightness	Source and requested level	Commanded brightness, actual source state, and relevant fault	Brightness units and calibration; available electrical/optical measurements
Stop illumination	Source or selected group	Off state and relevant fault	Response time and behavior on control loss

Illustrative commands:

Example	Result
UNe 100	Select UNe, enable it, and set brightness to 100
UNe 0 or UNe off	Turn UNe off

The syntax and brightness units are still to be settled with ICS.

Operating case example: named calibration illumination config

UNe ZImager Point Source. This is an illustration of the requested configuration.

config:
    name: UNe ZImager Point Source
    path: none  # don't care
    selector: zimage
    cal: in
    pointsource: in
    source: UNe
    brightness: 10

Protection, faults, and recovery

Conditions that permit lamp activation and what locally prevents hazardous illumination still need doing. Any hardware lockout/protection is yet to be defined and will be distinct from a software inhibit.

For a failed move, failed lamp, lost controller, or interruption, the measured state, affected capability, permitted recovery, and any effect on alignment/calibration need to be determined. Recovery cannot require moving every selector or restarting unrelated components.

Team notes: Controller consolidation, embedded/host interfaces, source inventory, actuator selection, exposure overlap, and source-ready indications remain open. These choices need another pass against the developing L2 and L3 requirements.