sartoriuslib

Async-first Python driver for Sartorius lab balances over RS-232 / USB. Speaks both wire protocols the hardware exposes — xBPI (binary, length-prefixed, checksum-protected, SBN-addressed) and SBI (ASCII command/response and autoprint) — behind a single semantic Balance API that decodes to the same typed Reading either way.

Built as a sibling to alicatlib: the same async core, sync facade, multi-device manager, fake transport, acquisition helpers, and pluggable sinks.

Status: alpha. Architecture is frozen and the public API is stable. Both protocol clients, the Balance facade, SartoriusManager, the recorder, first-party sink classes, the sync facade, and the sarto-* CLIs ship in the base install. Parquet and Postgres sinks lazy-load their optional backends. Hardware-coverage breadth and documentation polish are the active work; see the CHANGELOG.

Highlights

• One protocol-neutral API. Balance.poll(), tare(), zero(), identify(), status(), parameter R/W — the same calls work over xBPI and SBI, decoding to identical Reading / BalanceStatus / DeviceInfo models.
• Auto-detect. open_device(..., protocol=ProtocolKind.AUTO) does passive autoprint sniff → xBPI probe → SBI probe and reports clearly when nothing answers.
• Typed end to end. Unit.G, FilterMode.STABLE, Capability.HIRES_WEIGHT, frozen-dataclass responses, py.typed, mypy --strict clean.
• Typed errors. SartoriusError root with structured ErrorContext; every xBPI 0x01 error subtype maps to a distinct exception.
• Safety gates. Persistent and destructive operations require confirm=True. Family/capability mismatches are soft by default (warn + attempt); opt in to strict=True for pre-I/O refusal.
• Multi-device. SartoriusManager runs many balances concurrently — same-port requests serialize, different ports run in parallel.
• Acquisition built in. record(...) drives one or many devices on an absolute-target cadence into pluggable sinks: InMemorySink, CsvSink, JsonlSink, SqliteSink in core, plus ParquetSink and PostgresSink behind extras.
• Swappable transports. SerialTransport for hardware, FakeTransport for tests, fixture-backed transports for regression goldens.
• Sync or async. Async core on anyio; complete sync facade at sartoriuslib.sync via a blocking portal — every async method has a sync parity.
• CLI tooling. sarto-read, sarto-discover, sarto-capture, sarto-raw, sarto-decode, sarto-configure, and the sarto-diag reverse-engineering namespace.
• Lean core. pip install sartoriuslib pulls in anyio and anyserial — nothing else.

Install

pip install sartoriuslib

# optional sinks
pip install 'sartoriuslib[parquet]'   # ParquetSink (pyarrow)
pip install 'sartoriuslib[postgres]'  # PostgresSink (asyncpg)

Requires Python 3.13+. Linux, macOS, BSD, and Windows are supported via anyserial. On Linux, the user running sarto-* needs read/write access to the serial device — usually by joining the dialout group.

Quickstart (async)

import anyio
from sartoriuslib import open_device

async def main() -> None:
    async with await open_device("/dev/ttyUSB0") as bal:
        reading = await bal.poll()
        print(reading.value, reading.unit, "stable" if reading.stable else "unstable")
        await bal.tare()

anyio.run(main)

Sartorius balances ship from the factory speaking SBI. Pass protocol=ProtocolKind.SBI (or ProtocolKind.AUTO) on first contact; xBPI is a configuration choice you make on the device. See the troubleshooting guide.

Quickstart (sync)

from sartoriuslib.sync import Sartorius

with Sartorius.open("/dev/ttyUSB0") as bal:
    print(bal.poll())
    bal.tare()

Multi-device acquisition

import anyio
from sartoriuslib import SartoriusManager
from sartoriuslib.streaming import record
from sartoriuslib.sinks import CsvSink, pipe

async def main() -> None:
    async with SartoriusManager() as mgr:
        await mgr.add("bal1", "/dev/ttyUSB0")
        await mgr.add("bal2", "/dev/ttyUSB1")
        async with (
            record(mgr, rate_hz=10, duration=60) as stream,
            CsvSink("run.csv") as sink,
        ):
            await pipe(stream, sink)

anyio.run(main)

The recorder runs on an absolute target cadence (drift-free), batches samples per tick, and reports send/receive timing on every Sample. See examples/ for a runnable script that streams an Alicat MFC and a Sartorius balance into one shared SQLite database concurrently.

Command-line tools

sarto-discover /dev/ttyUSB0                       # probe + identify
sarto-read /dev/ttyUSB0 --protocol auto           # one decoded poll
sarto-capture /dev/ttyUSB0 --rate 10 --duration 60 --out run.csv
sarto-decode --xbpi 02 02 48 ...                  # offline frame decode
sarto-raw /dev/ttyUSB0 --xbpi 0x02 --confirm      # raw escape hatch
sarto-configure switch-protocol /dev/ttyUSB0 --confirm
sarto-diag snapshot /dev/ttyUSB0 --out diag.json  # reverse-engineering aids

All CLIs accept --fixture FILE to drive a scripted FakeTransport, so end-to-end tests and demos work without hardware.

Documentation

Full docs live at https://GraysonBellamy.github.io/sartoriuslib/. Useful entry points:

• Async quickstart / Sync quickstart
• Balances and capabilities
• Commands and safety tiers / Safety
• Streaming and acquisition / Logging
• Wire protocol reference
• Testing — FakeTransport, fixtures, hardware tiers
• Architecture (design doc)

Development

uv for env and lock management, hatchling + hatch-vcs for builds, ruff for format and lint, mypy --strict and pyright for types, AnyIO's pytest plugin for the test suite (parametrised across asyncio, asyncio+uvloop, and trio).

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

Hardware tests are gated behind SARTORIUSLIB_ENABLE_STATEFUL_TESTS=1 and SARTORIUSLIB_ENABLE_DESTRUCTIVE_TESTS=1 and require a connected balance.

See CONTRIBUTING.md for the workflow and SECURITY.md for the disclosure policy.

License

MIT. See LICENSE.