Analytical equipment

Verified against PyLabRobot 0.2.2 on 2026-10-01. This reference describes APIs without connecting to or commanding instruments.

Plate-reader frontend

Stable imports include:

from pylabrobot.plate_reading import (
    CLARIOstarBackend,
    Cytation5Backend,
    PlateReader,
    PlateReaderChatterboxBackend,
)

PlateReader is a resource and requires dimensions plus a backend:

PlateReader(name, size_x, size_y, size_z, backend, rotation=None,
            category="plate_reader", model=None,
            child_location=Coordinate(...), preferred_pickup_location=None)

Do not copy the stale constructor PlateReader(name="CLARIOstar", backend=CLARIOstarBackend()); the stable frontend requires size_x, size_y, and size_z.

Verified frontend methods include:

open(**backend_kwargs)
close(**backend_kwargs)
read_absorbance(wavelength, wells=None, use_new_return_type=False,
                **backend_kwargs)
read_fluorescence(excitation_wavelength, emission_wavelength, focal_height,
                  wells=None, use_new_return_type=False, **backend_kwargs)
read_luminescence(focal_height, wells=None, use_new_return_type=False,
                  **backend_kwargs)

In 0.2.2 use_new_return_type=False returns the first measurement's nested data matrix, despite the annotated List[Dict] return type. Set use_new_return_type=True to retain measurement dictionaries, timestamps, wavelengths and temperature. Chatterbox returns synthetic zero measurements, None for unselected wells and a NaN temperature; strict JSON exporters must represent missing temperature explicitly. An empty wells=[] means all wells because the frontend uses wells or plate.get_all_items().

Record exact arguments, plate/well mapping, settings, raw response, and package version. Wavelengths are nm and focal height is mm. The legacy default discards additional measurement records; do not use it for kinetics or multi-read data.

PlateReader does not expose a universal set_temperature method in the verified 0.2.2 frontend. Temperature, shaking, injectors, kinetics, pathlength, read mode, and optics are backend/model-specific; do not infer them from another reader.

Offline interface checks

PlateReaderChatterboxBackend is available for software-only frontend testing. It can exercise method calls and resource state without an instrument, but it does not simulate optics, plate seating, thermal behavior, gain, focus, measurement noise, or assay chemistry.

For import and method-presence checks without backend construction:

python3 skills/pylabrobot/scripts/inspect_backends.py \
  --expected-version 0.2.2 --strict

The inspector does not call setup() and makes no transport connection.

Released plate-reader inventory

The 0.2.2 module exports CLARIOstarBackend, Cytation5Backend, SynergyH1Backend, Byonoy and SpectraMax drivers, plus ExperimentalTecanInfinite200ProBackend and ExperimentalSparkBackend. The Experimental names remain significant. Verify the exact import and required serial/FTDI/USB/SiLA/microscopy extra without constructing a device.

The current hosted machine table describes development drivers, including Cytation 1 microscopy and Cytation 5 multi-mode reading. Its model labels do not establish matching modalities or firmware compatibility for every 0.2.2 backend. Avoid copying the old blanket Cytation 1 absorbance/fluorescence/ luminescence claim; check the exact model, optics, plate and implementation.

Plate-reader live-run checklist

Before a separately authorized connection or read:

1. Confirm instrument model, serial/device ID, firmware, approved transport, exclusive control, and current calibration/QC.
2. Confirm plate manufacturer/catalog, format, material, bottom, lid/seal, orientation, barcode, and correct seating.
3. Confirm read mode and units: wavelength(s), focal height, gain, flashes, integration, shaking, temperature, kinetics, injectors, well selection, and read direction as applicable.
4. Check tray/door state and robot/manual transfer path; prevent closing on an obstruction or moving a plate while a device is active.
5. Include blanks, standards, controls, expected ranges, saturation rules, and acceptance criteria.
6. Save raw data and complete settings before derived analysis.

Opening/closing a tray is physical motion. Never call it merely to test connectivity.

Scales

Stable frontend:

from pylabrobot.scales import Scale

Verified methods are:

read_weight(**backend_kwargs) -> float
tare(**backend_kwargs)
zero(**backend_kwargs)

get_weight() is a deprecated alias. read_weight() reports grams; stability and timeout semantics depend on the selected backend. The scale constructor requires a name, dimensions, and backend.

The released package provides the model-specific backend:

from pylabrobot.scales import MettlerToledoWXS205SDUBackend

The old pylabrobot.scales.mettler_toledo module is absent in 0.2.2. MettlerToledoWXS205SDU is a deprecated class that raises on construction; use the Backend-suffixed class. Do not instantiate it or call setup() during planning. The current inventory distinguishes models and suffixes; its Full entry is WXS205SDU/15, not a claim about every WXS205 variant.

Before live weighing, verify:

• model, port, units, resolution, range, calibration, leveling, warm-up, and environmental limits;
• tare container, stability/status flags, vibration, drafts, static, and evaporation;
• whether returned values are stable/net/gross and how errors are represented;
• physical placement/removal route and collision clearance.

Mass is not automatically volume. Converting grams to microlitres requires a validated density at the relevant temperature and uncertainty propagation. Do not assume water density equals exactly 1 g/mL.

Coordinating liquid handlers and analytical devices

Treat each device as a separate state machine:

• never overlap motion unless the workcell has an approved interlock and scheduler;
• transfer ownership of a plate explicitly between deck, arm, reader, scale, and operator;
• verify doors/trays/buckets are in the required state;
• use unique plate IDs and record handoff timestamps;
• stop safely on partial failure; do not blindly retry a measurement or move;
• distinguish software resource assignment from physical plate location.

An async Python call does not create a physical safety interlock.

Data integrity

For every measurement, retain:

• protocol and manifest revisions;
• PyLabRobot/backend version and instrument identity/firmware;
• plate/barcode and well map;
• complete acquisition settings and units;
• calibration/QC status, blanks/controls, timestamps, and error/status fields;
• unmodified raw output plus checksums;
• transformation code/version and rejected/out-of-range values.

Validate dimensions and well labels before joining measurement data to sample metadata.

Sources

Reviewed 2026-10-01: 0.2.2 released source files (plate_reading/plate_reader.py, plate_reading/chatterbox.py, scales/scale.py), current machine inventory, and release review. Native chatterbox tests cover selected-well masking and both return contracts; no reader, microscope or scale was connected.