alicatlib

Python library for Alicat Scientific instruments over serial — the full {flow, pressure} × {meter, controller} × {gas, liquid} matrix, plus the CODA Coriolis line. Covered prefixes include M- / MC- gas mass flow, P- / PC- gas pressure, L- / LC- liquid flow, the K-family (K- / KM- / KC- / KF- / KG-) CODA Coriolis prefixes, and all documented specialty variants (MCDW-, PCD-, LCR-, BASIS-, SFF-, …). The Medium model is flexible enough to handle devices configured for gas, liquid, or both — users narrow to the specific unit configuration via assume_media= on open_device.

alicatlib is focused on correctness, typed APIs, and reliable multi-device acquisition.

Status: beta. Documentation and release prep in progress; see docs/design.md for the architecture and remaining future work.

Highlights

• Typed end to end. Gas.N2, Unit.SCCM, Statistic.MASS_FLOW, frozen dataclass responses. py.typed shipped. mypy --strict passes.
• Declarative commands. One Command object per Alicat command with encoding, decoding, firmware gating, device-kind gating, and medium gating (gas vs. liquid, for CODA and friends) as metadata — adding a new command is ~50 lines.
• Typed errors. Distinct exception types for timeout, malformed response, unsupported firmware, and device error markers — all carrying structured ErrorContext for debuggability.
• Safety. Destructive operations (factory reset, baud change, exhaust) require confirm=True. Setpoints are range-checked before any I/O.
• Multi-device, correctly. AlicatManager runs many devices concurrently; same-port requests serialize via a shared lock, different ports run in parallel, resources unwind cleanly on partial-open failures.
• Acquisition built in. record() drives one or more devices at an absolute-target cadence with no cumulative drift, and pipe() drains samples into any SampleSink. First-party sinks: InMemorySink, CsvSink, JsonlSink, SqliteSink (stdlib WAL), plus ParquetSink and PostgresSink behind extras.
• Streaming mode. dev.stream(...) opens a bounded-memory StreamingSession that normalises the wire and fast-fails any concurrent request/response command on the same bus; NCS sets the device's continuous-stream rate on V10 firmware 10v05+.
• Swappable transports. SerialTransport for hardware, FakeTransport for tests; TCP / Modbus can land behind the same interface later.
• Sync or async. The core is async (built on anyio), and a sync facade (alicatlib.sync.Alicat) wraps it for scripts, notebooks, and REPLs.
• Lean core. pip install alicatlib pulls in anyio and anyserial — and nothing else. Parquet, Postgres, and docs live behind extras.

Install

pip install alicatlib
# optional sinks
pip install 'alicatlib[parquet]'
pip install 'alicatlib[postgres]'

Requires Python 3.13+.

Quickstart (sync)

from alicatlib.sync import Alicat

with Alicat.open("/dev/ttyUSB0") as dev:
    frame = dev.poll()
    print(frame.get_float("Mass_Flow"))
    dev.setpoint(50.0, "SCCM")

Quickstart (async)

import anyio
from alicatlib import Gas, open_device

async def main():
    async with await open_device("/dev/ttyUSB0") as dev:
        frame = await dev.poll()
        print(frame.get_float("Mass_Flow"))
        await dev.gas(Gas.N2, save=True)

anyio.run(main)

Development

Uses uv for env and lock management, hatchling for the build backend, ruff for format and lint, and mypy --strict for types.

uv sync --all-extras --dev
uv run pytest
uv run ruff format --check .
uv run ruff check .
uv run mypy

See CONTRIBUTING.md for the full workflow, and docs/design.md for the architectural design.

License

MIT. See LICENSE.