Table of Contents:
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,
Relevant Devices
Description | Qty | Source | Part Number |
|---|---|---|---|
Menlo Laser Frequency Comb | |||
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
Action | Notes | |
|---|---|---|
| 1 | Turn LFC On and Off | On is AstroComb and “off” is StandbyHi |
Required Adjustable Settings
Setting | When Needed | Notes | ||
|---|---|---|---|---|
Build | Observing | Maintenance | ||
Not Applicable | Comb settings are set and maintained by manufacturer. | |||
Required Telemetry
Will/Brad: this is the telemetry list from the LFC that NEID puts into their FITS headers. We’re planning to use the same list. However, I’m not sure how well these descriptions line up with how Menlo describes the same parameters. I presume it’s similar but flagging that here in case the two are different.
Parameter | Example Values | NEID FITS Keywords (for reference) | Report Frequency | Purpose | Notes | |
|---|---|---|---|---|---|---|
| 1 | LFC PCF Serial Number | VIS0002 | LFCPCFSN | PCF could be changed out at some point, this records which one was installed when | This has to be done by hand. | |
| 2 | LFC Amplifier Runtime | 16.171 | main.core.modules.Lifetime.mainAmpDuration | |||
| 3 | LFC PCF Runtime (s) | 1590962+ | LFCPCFRT | PCF has limited lifetime | This will be in the dispatcher internally | |
| 4 | LFC Fiberlock IR Intensity | 1332 | LFCFLIR | main.core.modules.ualigna.wobbling.intensityIr | ||
| 5 | LFC Fiberlock VIS Intensity | -36 | LFCFLVIS | main.core.modules.ualigna.wobbling.intensityVisible | ||
| 6 | LFC Filtered Offset Freq (Hz) | 244999999.75 | LFCFO | RR Comb counted main.core.functionalLayer.rr.frequencies.combCounted | ||
| 7 | LFC Filtered Offset Freq Ref (Hz) | 250000000.00 | LFCFOREF | RR Comb setpoint main.core.functionalLayer.rr.frequencies.combSetpoint | ||
| 8 | LFC Filtered Rep Rate (Hz) | 20000000000.000 | LFCFR | RR filtered counted main.core.functionalLayer.rr.frequencies.filteredCounted | ||
| 9 | LFC Filtered Rep Rate Ref (Hz) | 20000000000.000 | LFCFRREF | RR filtered setpoint main.core.functionalLayer.rr.frequencies.filteredSetpoint | ||
| 10 | CEO Filtered setpoint | 572000000 | LFCCEOFR | filtered setpoint main.core.functionalLayer.ceo.frequencies.filteredSetpoint | ||
| 11 | CW Freq | 288005612438981 | LCFCWFR | main.core.functionalLayer.cw.wavemeter.frequency | ||
| 12 | CW Mode number | 1152023 | LFCCWMDN | main.core.functionalLayer.cw.wavemeter.modeNumber | ||
| 13 | CW Frequency Error | -107561019 | LFCCWFER | main.core.functionalLayer.cw.wavemeter.error | ||
| 14 | CW Freq Ref | 288005720000 | LFCCWFRF | main.core.functionalLayer.cw.wavemeter.expected | ||
| 15 | LFC Status Bitfield | LFCSTAT |
Required Alarms
Parameter | Threshold | Notes | |
|---|---|---|---|
| 1 | |||
| 2 |
Relevant Datasheets & Manuals
Description | File | Source | |
|---|---|---|---|
| 1 | ClientAPI.zip: documentation of and client libraries for the remoting interface of the system. The documentation is system-agnostic, describing the data-format and some of the general data structures you will encounter. The client libraries are for Python, JavaScript, C++ and C# users, each with a small bare-bones example of reading values. | Email from Tilo Steinmetz at Meno (email text at left) | |
| 2 | API-Docs.zip: documentation of many of the classes exposed through the API. Frankly, this documentation is still pretty erratic: some parts are not documented at all while other parts still contain internals in the user-documentation. But once you have established connection to the system, this is still the best source available for details of the objects tree you see through the API | Email from Tilo Steinmetz at Meno (email text at left) | |
| 3 | menlosystemcore_with_plugins-1.7.0-installer.exe, coreui-2.5.0-installer.exe and systemlogic.zip: releases of the PC-version of the main application and the GUI component, to allow you to install on any of your (Windows-)PCs and get them to pretend to be an LFC. Useful for testing before the actual system gets shipped. Please note: we expect to have one more bugfix release of the software and to do lots of editing of the systemlogic (which is a high-level, scriptable configuration of the system). The bugfix release is needed because the GUI still crashes sometimes during startup and the systemlogic as attached still needs some work: a few elements GUI pages are not working and the automation is still missing | Email from Tilo Steinmetz at Meno (email text at left) | |
| 4 | |||
| 5 | OUTDATED Fiber Comb Control software User Manual | From NEID Menlo comb | |
| 6 | OUTDATED Software Interface Control Document for XLMRPC-protocol | From NEID Menlo comb |
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.
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 |
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