PreciseFlex: the configuration as data - cameras counted, saved, recorded and declared

[BioCam]

The Problem

What an arm reports at setup lives only for the session. It cannot be written down, compared with another session, or handed to code that runs without the arm, and a caller who knows which arm they expect has no way to say so: setup adopts whatever answers.

is_vision_gripper is read from the last letter of the model name. A name says what was ordered, not what is fitted: an arm named without a V can carry a camera gripper, and one named with it may not.

The controller takes one connection and matches a reply to its command only by order. Nothing stops two callers from writing before either reads, and each would then take the other's reply with no error to show it.

Solution

• _locked_exchange holds a lock around each write and its reply; send_command goes through it, and the reply check is split out as _ensure_successful so a reply in another grammar can be read through the same exchange. The interrupt halt bypasses the lock.
• Discovery counts the cameras through the controller (VToolProperty System CameraCount) when its IntelliGuide module is loaded. camera_count is on the configuration, has_vision_gripper is true when it is above 0, and is_vision_gripper warns and answers has_vision_gripper.
• save_configuration(path) writes the configuration as JSON in the STAR's shape: the device's own under device, and each fitted feature's beside it under its name (arm, gripper, rail). read_configuration(path) reads the sections back into the dataclasses, with axes by name and ranges as tuples. Live state is not written, and a field or feature the driver does not know is left out.
• driver/recordings/pf400_extended_400mm.json is what an extended-reach PF400 with 400 mm of Z travel and a two-camera gripper answered, saved by the driver at setup on the arm, with its serial blanked.
• declared_configuration_json names a file save_configuration wrote, read into declared when the driver is built, as the STAR reads its own. Discovery raises, naming each difference, when it does not describe the device that answers: what is fitted, its link and tool lengths, its soft limits. Identity is not compared, so a declaration taken off one arm stands for another of the same build.

The one change on the wire is the camera count: setup reads VToolProperty System CameraCount after version on an arm with IntelliGuide, answered in the tests as the arm answered it (2).

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