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Table of Contents:

Table of Contents

Page Status

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Introduction

The Laser Frequency Comb (LFC) is a ‘black box’ system purchased from Menlo Systems. It provided a high-line density calibration source for KPF that offers high wavelength stability,

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Relevant Devices

Description

Qty

Source

Part Number

Menlo Laser Frequency Comb

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Relevant Functional Block Diagram

Note the LFC computer will sit on the Keck ‘ops’ network at the summit, not the KPF private network.

Software Actions

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Action

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Notes

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Not applicable

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-

Note: No KPF software actions required. That is, we don’t need to control the comb, only get telemetry values from it.

Required Adjustable Settings

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Setting

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When Needed

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Notes

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Build

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Observing

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Maintenance

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Not Applicable

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Comb settings are set and maintained by manufacturer.

Required Telemetry

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Parameter

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Report Frequency

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Purpose

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Notes

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f_rep

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TBD

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Used to define comb output frequencies

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Should be written to FITS header

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f_0

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TBD

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Used to define comb output frequencies

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Should be written to FITS header

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Comb lock status

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TBD

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Ensure comb stability is locked.

Required Alarms

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Parameter

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Threshold

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Notes

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Relevant Datasheets & Manuals

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Description

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File

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Source

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Fiber Comb Control software User Manual

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View file
name5.1) Fiber Comb Control-1.pdf

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From NEID Menlo comb

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Software Interface Control Document for XLMRPC-protocol

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View file
name5.5) Interface Control Document.pdf

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From NEID Menlo comb

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Relevant Datasheets & Manuals

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Relevant Software

The Menlo LFC uses websockets to communicate with other processes.

Menlo has written an API layer in Python that has two requirements:

Menlo also suggests that you can use

with pywebchannel but you have to roll your own interface.

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Dispatcher

Keyword

Value

Type

AMPLIFETIME

22.004 sec

Float

DEVICE(#)

Menlo LFC - device name

AstroComb_AU06112

String

PCFSERIAL

####### - serial number of PCF

String

OPERATIONMODE

0 - AstroComb (or On)

1 - StandbyHi (preferred when not in use)

2 - StandbyLow

3 - Off

4 - Manual

Enumerated

Values 2 through 4 are NOT writeable.

IRFLUX

13451234

Integer - no units

VISFLUX

12341234

Integer - no units

OFFSETFREQ

135928345 Hz

Double

LFCCEOFR

-30000000.00 Hz

CEO filtered setpoint

Double

LFCCWFERR

34412342 Hz

CW frequency error

Double

LFCCWFREF

-30000000 Hz

CW reference frequency

Double

LFCCWFREQ

288005504412342 Hz

CW frequency

Double

LFCCWMDN

0

Integer

LFCF0

250000163.02 Hz

LFC filtered offset frequency

Double

LFCFOREF

250000000.00 Hz

LFC filtered offset freq ref

Double

LFCFRR

20000013041.2758 Hz

LFC Filtered Rep Rate

Double

LFCFRREF

20000000000.0000 Hz

LFC Filtered Rate Ref

Double