qmi.instruments.thorlabs.apt_protocol

Module for the APT protocol used by Thorlabs. The documentation for the protocol can be found here https://www.thorlabs.com/Software/Motion%20Control/APT_Communications_Protocol.pdf

Classes

`AptChannelHomeDirection`(value)	Possible values for the `home_direction` field in the homing parameters.
`AptChannelHomeLimitSwitch`(value)	Possible values for the `limit_switch` field in the homing parameters.
`AptChannelJogDirection`(value)	Jog direction
`AptChannelState`(value)	Channel state
`AptChannelStopMode`(value)	Channel stop mode
`AptProtocol`(transport[, apt_device_address, ...])	Implement the Thorlabs APT protocol primitives.
`HomeParams`(home_direction, limit_switch, ...)	Homing parameters for the controller.
`MotorStatus`(forward_limit, reverse_limit, ...)	Status bits of motor controller.

class qmi.instruments.thorlabs.apt_protocol.AptChannelState(value): Channel state

class qmi.instruments.thorlabs.apt_protocol.AptChannelStopMode(value): Channel stop mode

class qmi.instruments.thorlabs.apt_protocol.AptChannelJogDirection(value): Jog direction

class qmi.instruments.thorlabs.apt_protocol.AptChannelHomeDirection(value): Possible values for the home_direction field in the homing parameters.

class qmi.instruments.thorlabs.apt_protocol.AptChannelHomeLimitSwitch(value): Possible values for the limit_switch field in the homing parameters.

class qmi.instruments.thorlabs.apt_protocol.HomeParams(home_direction: AptChannelHomeDirection, limit_switch: AptChannelHomeLimitSwitch, home_velocity: float, offset_distance: float)

Homing parameters for the controller.

home_direction

Direction of moving to home (1 = forward, 2 = reverse).

Type:: qmi.instruments.thorlabs.apt_protocol.AptChannelHomeDirection

limit_switch

Limit switch to use for homing (1 = reverse, 4 = forward).

Type:: qmi.instruments.thorlabs.apt_protocol.AptChannelHomeLimitSwitch

home_velocity

Homing velocity in degrees/second or mm/second.

Type:: float

offset_distance

Distance of home position from home limit switch (in degrees or mm).

Type:: float

class qmi.instruments.thorlabs.apt_protocol.MotorStatus(forward_limit: bool, reverse_limit: bool, moving_forward: bool, moving_reverse: bool, jogging_forward: bool, jogging_reverse: bool, homing: bool, homed: bool, tracking: bool, settled: bool, motion_error: bool, current_limit: bool, channel_enabled: bool)

Status bits of motor controller.

Note: Some of the status bits do not seem to work with the K10CR1.

moving_forward

True if the motor is moving in forward direction.

Type:: bool

moving_reverse

True if the motor is moving in reverse direction. It looks like move_forward and move_reverse are both active when the stage is moving, regardless of the actual direction of movement.

Type:: bool

jogging_forward

True if the motor is jogging in forward direction.

Type:: bool

jogging_reverse

True if the motor is jogging in reverse direction. It looks like jogging_reverse is also active when jogging in forward direction, while jogging_forward is never active.

Type:: bool

homing

True if the motor is homing.

Type:: bool

homed

True if homing has been completed.

Type:: bool

motion_error

True if an excessive position error is detected.

Type:: bool

current_limit

True if the motor current limit has been reached.

Type:: bool

channel_enabled

True if the motor drive channel is enabled.

Type:: bool

class qmi.instruments.thorlabs.apt_protocol.AptProtocol(transport: QMI_SerialTransport, apt_device_address: int = 80, host_address: int = 1, default_timeout: float | None = None)

Implement the Thorlabs APT protocol primitives.

create(msg_type: _AptMessage, **kwargs: Any) → _AptMessage

Call for creating and returning a message instance. Valid for request and get messages.

Returns:: The created message instance.
Return type:: apt_message

send_message(msg: _AptMessage) → None

Encode and send a binary message to the instrument. Before sending a new command, do a non-blocking read to consume a potential old message from the instrument. This prevents a buildup of unhandled notification messages from the instrument after several move_XXX() commands.

Parameters:: msg – An _AptMessage instance.

read_message(timeout: float | None) → _AptMessage

Read and decode a binary message from the instrument.

Parameters:: timeout – A timeout value for reading the messages.
Returns:: The obtained message instance with data from the buffer.
Return type:: message
Raises:: QMI_InstrumentException – If an unknown or partial message is received.

wait_message(message_type: type, timeout: float | None) → _AptMessage

Wait for a specific message type from the instrument.

Any other (valid) messages received from the instrument will be discarded.

Parameters:

message_type – Type of message to wait for.
timeout – Maximum time to wait for the message in seconds.

Returns:

The received message.

Raises:

QMI_TimeoutException – If the expected message is not received within the timeout.

ask(request_msg: _AptMessage, reply_msg: _AptMessage | _AptMessageHeader) → _AptMessage

A helper function for requests that expect a response.

Parameters:

request_msg – The request message to be sent.
reply_msg – The reply message expected to be received.