Menlo FXE¶
From: Menlo Systems
Class: herosdevices.hardware.menlo.fxe.FXE
Driver Quality Index: alpha
Additional Information Check before use¶
Menlo OFC Setup
This driver is split into one core device and several modules attached to it.
OFC opens the single QWebChannel websocket connection to the comb and
exposes its raw control/status tree via get_node/set_node/explore.
Each functional-layer module (DDS,
LaserLock, DualLaserLock,
FXE, RepetitionRate,
CEO, Oscillator) is a
separate HERO. It takes the already-running OFC
HERO as a constructor argument via BOSS’s "ofc": "$device_menlo_ofc" reference, so all modules share the
one physical connection instead of each opening their own.
See examples/menlo/ofc.json for a complete BOSS config wiring one comb with all its modules.
Some CW channels lock two wavelengths through one shared lock loop, with two separate frequency-distribution
blocks instead of one. Deploying plain LaserLock against one of these fails, since it hardcodes a single
frequency-distribution node name that these channels don’t have. Use
DualLaserLock instead, passing both wavelengths’ node names
explicitly; see examples/menlo/ofc.json for an example.
FXE wraps the comb’s 16-channel frequency counter. Unlike the other
modules, it has no default observables, since which channel carries which signal is deployment-specific.
Pass observables for the channels relevant to your comb, e.g. a beat on channel 3:
"arguments": {
"ofc": "$device_ofc",
"observables": {
"cw_beat": {"path": "counterFrequencies.channel03", "unit": "Hz"}
}
}
Node paths (used in get_node/set_node/observables) are firmware-dependent and not documented by
Menlo. Use format_tree() to find them interactively:
>>> print(ofc.format_tree("functionalLayer.rrSettings", depth=2))
functionalLayer.rrSettings
|-- dds
| |-- ddsFrequency = 28286800
| |-- outputOn = True
| `-- outputPower = 0.64
|-- mainControls
| |-- fastOutput ...
| |-- lock = True
| `-- slowOutput ...
`-- repetitionRate
|-- rrCounterRepRate = 250105340.0
`-- rrTargetBeatRF = 250105340
Nodes shown as ... are unexpanded branches; raise depth or call format_tree again rooted at that
path to descend further. explore() returns the same tree as a plain
dict instead of a rendered string, if you want to process it programmatically.
For anything specific to your comb (e.g. a customer-specific fiber-noise-cancellation module),
poll or control it directly instead of adding a new class: every module accepts an observables argument,
merged on top of its DEFAULT_OBSERVABLES, and OFC.get_node/OFC.set_node give full read/write
access to any node regardless.
"arguments": {
"host": "IP_OR_HOSTNAME",
"observables": {
"fnc578_locked": {"path": "functionalLayer.fnc578Settings.mainControls.lock", "unit": ""},
"fnc1157_locked": {"path": "functionalLayer.fnc1157Settings.mainControls.lock", "unit": ""}
}
}
Important
The OFC device’s _ensure_connected method must be reachable from the other modules over the
network. HEROS excludes underscore-prefixed methods from a RemoteHERO proxy unless marked
force_remote, so the OFC row in your BOSS config needs:
"extra_decorators": [["_ensure_connected", "heros.inspect.force_remote"]]
See examples/menlo/ofc.json for this in context.
Warning
The PyPI package named pywebchannel is an unrelated project; installing it will not work. Install it
from source instead:
pip install "pywebchannel @ git+https://github.com/MenloSystems/pywebchannel"
pywebchannel is not declared as a project dependency, so this install step must be run manually wherever the Menlo driver
is used: locally, in CI, and in any Docker image.
In a Docker Container deployment via BOSS, use the BOSS_PIP_PKGS environment variable (see the
BOSS documentation)
instead of extending the image:
services:
device_ofc:
image: registry.gitlab.com/atomiq-project/herosdevices:latest
restart: always
network_mode: host
volumes:
- ./ofc.json:/ofc.json:ro
environment:
- BOSS_PIP_PKGS=pywebchannel@git+https://github.com/MenloSystems/pywebchannel
command: python -m boss.starter -u file:///ofc.json --log info
Driver for the frequency-counter (FXE) module of a Menlo Systems frequency comb.
Wraps the OFC’s functionalLayer.fxeSettings sub-tree, a fixed, singleton module (there is only one FXE
counter per OFC, so unlike DDS/
LaserLock there is no funclayer_identifier to select). Confirmed
reachable directly at functionalLayer.fxeSettings (the same object is also reachable via
modules[“SYNCRO3U”].functionalLayer.fxeSettings).
Unlike the other functional-layer modules, FXE has no lock loop or DDS - it is a pure 16-channel
frequency counter. Use channel_frequency() to read a specific channel; which channel carries
which physical beat signal is deployment-specific, so there is no fixed per-channel DEFAULT_OBSERVABLES
here - pass observables to poll the channels relevant to your comb.
Bold arguments are mandatory. For more information on the listed arguments refer to the class documentation: herosdevices.hardware.menlo.fxe.FXE If parameters appear in this list but not in the class definition, please recursively check the linked base classes for the definition of the parameter.
Argument |
Type |
Default Value |
Description |
|---|---|---|---|
ofc |
<class ‘herosdevices.hardware.menlo.ofc.OFC’> |
The OFC HERO this counter belongs to. |
|
observables |
dict[str, dict[str, str]] | None |
None |
Additional observables to poll, merged on top of DEFAULT_OBSERVABLES, see |
The following JSON strings can be used to start a HERO device representation of FXE using BOSS.
{
"_id": "device_menlo_ofc_fxe",
"classname": "herosdevices.hardware.menlo.FXE",
"arguments": {
"ofc": "$device_menlo_ofc"
},
"datasource": {
"async": false,
"interval": 15
}
}
Note
This example contains a variable that references another HERO with $.
from examples/menlo/ofc.json
{
"_id": "my_FXE",
"classname": "herosdevices.hardware.menlo.fxe.FXE",
"arguments": {
"ofc": "<class 'herosdevices.hardware.menlo.ofc.OFC'>",
"observables": null
}
}
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