Changelog#

All notable changes to QInstrument are documented here. The format follows Keep a Changelog.

3.0.2 — 2026-04-29#

Fixed#

  • lib/QInstrumentWidget, lib/QInstrumentTree: _firstShow() now calls _syncProperties() before _startDeviceThread(). Previously the sync ran after the device was moved to its worker thread; because _syncProperties() uses direct Python method calls (not Qt queued slots), the serial I/O executed on the main thread while the QSerialPort was owned by the worker thread. This triggered Qt’s “QSocketNotifier: cannot be enabled from another thread” warning, caused waitForReadyRead() to fail, and left every property getter returning None — producing errors such as “Could not set harmonic to None” and locking the UI. Running the sync on the main thread (before the move) eliminates the cross-thread access entirely.

3.0.1 — 2026-04-29#

Fixed#

  • lib/QInstrumentWidget, lib/QInstrumentTree: removed automatic startPolling() call from _firstShow(). Auto-polling caused a race condition when SR830/SR844 instruments were embedded in scan-driven applications that also called report() from the main thread. Callers that need continuous updates must now invoke startPolling() explicitly (via QMetaObject.invokeMethod(device, 'startPolling', QueuedConnection) so it executes on the worker thread).

Changed#

  • instruments/StanfordResearch/SR830, instruments/StanfordResearch/SR844: removed x, y, r, and theta from the property registry and dropped QPollingMixin from the class hierarchy. Both instruments are now pure control panels (sensitivity, time constant, frequency, etc.), consistent with their widgets and trees. The report() method remains as the measurement API for embedding applications. SR844 additionally drops reference_frequency and if_frequency.

  • instruments/PriorScientific/Proscan: QProscan now inherits QPollingMixin and implements _poll() — each cycle queries position() and active_limits(), emitting positionChanged and a new limitsChanged signal. POLL_INTERVAL defaults to 200 ms. QProscanWidget drops its main-thread QTimer and cross-thread direct calls; it now connects to the device signals and starts polling via invokeMethod(QueuedConnection) in _firstShow(), keeping all serial I/O on the worker thread.

  • lib/QPollingMixin: updated docstring to reflect that startPolling() must be called explicitly; it is no longer started automatically by QInstrumentWidget or QInstrumentTree.

3.0.0 — 2026-04-29#

Changed#

  • lib/QSerialInterface.py: non-blocking mode removed entirely. The blocking property, dataReady signal, _buffer, and _handleReadyRead slot have been deleted. receive() and readn() use waitForReadyRead() directly and are intended to run in a dedicated worker thread rather than on the GUI thread. The QEventLoop-based approach introduced in 2.4.0 has been reverted; waitForReadyRead() is safe in a worker thread and avoids reentrancy hazards.

  • lib/QSerialInstrument.py: QSerialInterface is now constructed as a Qt child of the instrument (parent=self), so it migrates automatically when the instrument is moved to a worker thread.

  • lib/QInstrumentWidget.py: on first show, the device is moved to a dedicated QThread so serial I/O no longer competes with the GUI event loop. Property sync is now fire-and-forget (device.get()); values are delivered asynchronously via the propertyValue signal to a new _onPropertyValue slot that applies them with signals blocked. closeEvent stops the thread before saving settings.

  • lib/QInstrumentTree.py: full parity with QInstrumentWidget — same first-show threading lifecycle, _restoreSettings() with QReconcileDialog, and closeEvent save. HARDWARE_DOMINANT class attribute added.

  • lib/Configure.py: save() accepts an optional settings parameter to avoid cross-thread reads when the device lives in a worker thread.

  • lib/lazy.py: values_differ() extracted from QInstrumentWidget (was duplicated) and exported in __all__. find_fake_cls() added to __all__.

  • lib/QAbstractInstrument.py: handshake(), expect(), and getValue() moved to QSerialInstrument. QAbstractInstrument now has no concept of hardware communication; it models only instrument state (property and method registry). A future transport subclass (e.g. QGPIBInstrument) would provide the same communication helpers over a different physical layer.

  • lib/QAbstractInstrument.py: persist metadata flag removed from settings getter and setter. The base class now treats all writable properties as persistent. Instruments that need to exclude specific properties from save/restore should override settings in the instrument subclass (see QProscan).

  • instruments/PriorScientific/Proscan/instrument.py: speed and zspeed are excluded from save/restore via a settings override and a _VOLATILE class attribute, replacing the former persist=False argument to registerProperty().

  • lib/QInstrumentWidget.py: _firstShow() now invokes startPolling via a queued QMetaObject.invokeMethod call after moving the device to its worker thread, if the device inherits QPollingMixin. closeEvent() calls stopPolling() before stopping the thread when the device supports it.

  • lib/QInstrumentTree.py: same polling integration as QInstrumentWidget.

  • instruments/StanfordResearch/SR830/instrument.py: QSR830 now inherits QPollingMixin and overrides _poll() to use the SNAP?9,3,4 batch command, emitting frequency, r, and theta as propertyValue signals on every tick.

  • instruments/StanfordResearch/SR844/instrument.py: same as SR830.

Added#

  • lib/QPollingMixin.py: new mixin class that adds a self-scheduling poll loop to any instrument. startPolling() begins the loop; stopPolling() ends it (safe to call from any thread). The loop uses QTimer.singleShot so the next query starts only after the current one completes, preventing query backup under any load. POLL_INTERVAL (default 0) sets the delay between the end of one response and the start of the next. The default _poll() calls get() for every registered property; instruments that can batch multiple properties into a single query should override it.

Removed#

  • lib/QInstrumentWorker.py: QInstrumentWorker removed. Use QPollingMixin on the instrument class instead.

  • instruments/StanfordResearch/SR830/worker.py: QSR830Worker removed. Polling is now handled by QSR830._poll().

  • instruments/StanfordResearch/SR844/worker.py: QSR844Worker removed. Polling is now handled by QSR844._poll().

2.4.1#

Fixed#

  • lib/QSerialInterface.py: receive() now decodes bytes with errors='replace' instead of the strict default. Prevents a UnicodeDecodeError when find() scans a port occupied by an instrument that responds to *IDN? with non-UTF-8 bytes.

2.4.0#

Changed#

  • lib/QSerialInterface.py: receive() and readn() switched from waitForReadyRead() to a scoped QEventLoop driven by readyRead and a QTimer. (This approach was reverted in the following release; see Unreleased above.)

Deprecated#

  • lib/QInstrumentWorker.py: QInstrumentWorker is deprecated and will be removed in a future release.

2.3.2#

Fixed#

  • lib/QInstrumentWidget.py: showEvent now defers first-show reconciliation via QTimer.singleShot(0, ...) instead of calling _restoreSettings() synchronously. Opening a QReconcileDialog (nested exec() event loop) from inside Qt’s show-event sequence caused a segfault on all platforms; the deferred call runs after the show sequence completes, eliminating the re-entrancy.

2.3.1#

Fixed#

  • lib/lazy.py: new make_getattr(lazy, package) factory replaces the hand-written __getattr__ boilerplate in every instrument __init__.py. The resolved value is cached back into the package __dict__ via sys.modules[package].__dict__, preventing Python’s import machinery from shadowing it with the submodule object on subsequent accesses. All eleven leaf instrument packages updated to use the factory.

2.3.0#

Added#

  • instruments/__init__.py: dynamic __getattr__ aggregates all instrument classes from subpackages via pkgutil.walk_packages. Instrument classes can now be imported directly from QInstrument.instruments (e.g. from QInstrument.instruments import QDS345Widget, QFakeSR830) without specifying the full subpackage path. Adding a new instrument requires no changes to instruments/__init__.py.

2.2.0#

Added#

  • QAbstractInstrument.registerProperty accepts a persist keyword (default True). Properties with persist=False are excluded from settings and never written to or restored from configuration files. Proscan: speed and zspeed set to persist=False.

  • Configure.read() reads the saved JSON without applying it, enabling comparison before commit.

  • QInstrumentWidget._restoreSettings(): on first show, hardware state is compared against the saved configuration. If no file exists the hardware state is saved; if values match nothing happens; if they differ a QReconcileDialog is shown so the user can choose which values to adopt. HARDWARE_DOMINANT = True on QProscanWidget makes “Keep Hardware” the default button.

  • QInstrumentWorker: runs an instrument in a dedicated QThread with a zero-interval poll loop. QSR830Worker and QSR844Worker emit [frequency, R, theta] via SNAP?9,3,4.

  • Opus laser: STATUS? property returns True (ENABLED) or False (DISABLED); logs a WARNING when DISABLED is received.

  • Opus laser: CONTROL=POWER sent in identify() to establish power-control mode on every connection.

Fixed#

  • QLedWidget rewritten to use QPainter instead of QSvgRenderer. Eliminates the QtSvg dependency and fixes a silent packaging bug where QLedWidget.svg was never included in the distributed wheel, causing FileNotFoundError on construction for PyPI installs.

  • Opus laser: POWER=, CURRENT=, ON, and OFF setters now call handshake() instead of transmit(), consuming the acknowledgement response and preventing read desynchronisation.

  • QInstrumentWidget.set(): replaced blockSignals(True/False) pair with QSignalBlocker so signals are correctly restored even if the setter raises.

2.1.0#

Added#

  • QInstrumentRack now supports drag-to-reorder instrument slots. A ⋮ drag handle appears on each slot; dragging highlights the target with a colored bar and commits the move on release.

  • QInstrumentRack close button (×) overlaid on each slot.

  • QInstrumentRack.editable property (default True) hides or shows the toolbar, drag handles, and close buttons as a unit. Set editable=False for embedded rack contexts where the instrument set should be fixed.

  • -f / --fake command-line flag for the qinstrument CLI and QInstrumentRack.example(): loads all instruments in fake (simulated) mode without probing hardware. The flag is remembered by the rack, so instruments added interactively via the picker dialog also use fake devices.

  • QLedWidget: disabled widgets now render as WHITE/OFF (grayed out) regardless of their current color. Re-enabling restores the original color and state.

  • Tests: QInstrumentRack, QLedWidget, and QRotaryEncoderSpinBox now have pytest coverage.

Fixed#

  • Opus widget: poll timer is no longer started when the device port is not open, preventing spurious “Cannot send data: device is not open” log messages at startup.

  • Opus widget: maximum_power is now initialized from the model subclass constant (MAXIMUM_POWER) rather than a hard-coded default.

2.0.0#

Added#

  • Instruments are now organized in a two-level manufacturer hierarchy: instruments/<Manufacturer>/<Name>/. The instrument picker in QInstrumentRack discovers all packages that contain a widget.py at this depth.

  • Novanta Opus family: Opus base class plus Opus532, Opus660, and Opus1064 model subclasses. Each subclass sets WAVELENGTH, MINIMUM_POWER, and MAXIMUM_POWER as class attributes — no code duplication.

  • QInstrumentRack: “Add instrument…” toolbar button that opens a picker dialog listing all discovered instrument widgets.

  • QInstrumentRack: right-click context menu on each instrument slot to remove it at runtime.

Changed#

  • All existing instrument packages moved to their manufacturer subdirectory. Import paths change from QInstrument.instruments.<Name> to QInstrument.instruments.<Manufacturer>.<Name>.

1.3.0#

Added#

  • QInstrumentTree: a pyqtgraph ParameterTree-based inspector that presents all registered properties and methods for any instrument without requiring a .ui file. Properties are editable live; methods appear as buttons. Read-only properties are displayed but cannot be edited.

  • tree.py module added to each instrument package (QDS345Tree, QSR830Tree, QOpusTree, etc.).

  • [tree] optional dependency (pip install 'QInstrument[tree]') pulls in pyqtgraph>=0.13.

  • QInstrumentTree.fields / FIELDS: restrict the parameter tree to a named subset of properties and methods.

1.2.0#

Added#

  • registerProperty accepts a debounce keyword (milliseconds). QInstrumentWidget coalesces rapid UI changes and sends only the final value to the device after the user pauses. Designed for controls (e.g. laser power) that must not receive a rapid stream of intermediate values.

  • QJoystick: padColor and knobColor style properties, setRange() method, and several paint-event improvements.

Changed#

  • IPGLaser widget overhauled: LED fault indicator, aiming-beam toggle, emission toggle, and improved status polling.

1.1.0#

Added#

  • QInstrumentRack: top-level widget that holds multiple QInstrumentWidget instances in a vertical layout.

  • qinstrument CLI entry point (also invokable as python -m QInstrument). With no arguments it restores the last session; with instrument names it loads those instruments.

  • Instrument list is persisted to ~/.QInstrument/QInstrumentRack.json on close and restored on next launch.

1.0.2#

Fixed#

  • QSerialInterface: corrected PyQt6 compatibility — integer enum values are now accessed via the long-form scoped path (BaudRate.Baud9600, etc.) throughout.

1.0.1#

Added#

  • GitHub Actions CI workflow: runs the full test suite on push/PR.

1.0.0#

Added#

  • PiezoDrive PDUS210 ultrasonic amplifier: fully migrated to the registerProperty() API with fake device and widget.

  • Configure: JSON-based save/restore gated on the _shown flag so test widgets closed during teardown do not write config files.

  • Expanded pytest suite covering QSerialInterface and QInstrumentWidget auto-binding.

0.4.0#

Added#

  • pyproject.toml-based packaging; installable from PyPI as pip install QInstrument.

  • Initial Sphinx documentation published to Read the Docs.

  • pytest test suite.

  • LICENSE.md (GPLv3).