Calibration Unit Compensators

Overview

When sources and filters change within the calibration unit, the image of the source moves with respect to the fiber. We had expected to compensate for these motions during alignment, but in practice this has not been possible.

As such, we have added two motorized compensators into the system, which will correct alignment for each source (8x) and filter (12x) combination. One motorized stage will move the exisiting beamsplitter in pitch and yaw, and the other will move a new fold mirror in pitch and yaw.

The position of these motors will be determined via a look-up table (i.e. if source is A and filter1 is B and filter2 is C, move mirror1 to X1,Y1 and move mirror2 to X2,Y2).

Relevant Devices

Description	Qty	Source	Part Number	Link
Galil 4040 Motor Controller	1	Galil	DMC-4040(MO)-C022(5V)-I000-D4040	https://www.galil.com/order/part-number-generator/dmc-40x0#DMC-4040(MO)-C022(5V)-I000-D4040
Motorized Actuator, Miniature, 12 mm Travel, Stepper, 25-pin D-Sub	4	Newport	TRA12PPD	https://www.newport.com/p/TRA12PPD

Relevant Functional Block Diagram

Software Actions

	Action	Notes
1	Home	Each motor will need a home command, where the actuator is retracted until a limit switch is hit.
2	Move to a position	Position given by number of steps away from home.
3	Two modes: automatic and manual	Automatic mode: Dispatcher reacts to any of the following: Octagon Source Change ND1 Filter Wheel Filter Change ND2 Filter Wheel Filter Change The dispatcher will then move all 4 compensator mirrors to the correct positions for the new source and filter wheel settings. Manual mode: the dispatcher does not react to changes of the sources or filter wheels.
4	Error catching	Motors can never be commanded beyond XXXXX steps as it will cause the actuator to damage itself by extending too far.

Required Adjustable Settings

Setting

When Needed

Notes

Build

Observing

Maintenance

Look up table of positions

YES

NO

YES

Look-up table contains a set of 4 motor positions for each combination of:

octagon source
ND1 filter wheel position
ND2 filter wheel position

Required Telemetry

	Parameter	Report Frequency	Purpose	Notes
1
2

Required Alarms

	Parameter	Threshold	Notes
1
2

Relevant Datasheets & Manuals

	Description	File	Source
1
2

Relevant Software

	Description	File	Source
1
2

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