devices.owis:SMS

OWIS SMS motor controller class for stepper motor control.

Usage

devices.owis:SMS(
    interface,
    steps_per_revolution=200,
    gear_ratio=1400,
    angle_ratio=540,
    limits=None,
    **kwargs,
)

Interface to the SM INT controller with two SMK 02-Z stepper motor drivers. By default it is configured for a rotary stepper motor with 200 steps per revolution and a 1400:1 gear ratio, converting steps to degrees. Up to 4 axes (X, Y, Z, R) are supported with absolute and relative movement commands.

Parameters

interface: str: VISA address, e.g. ASRL/dev/ttyUSB0::INSTR.
steps_per_revolution: int = 200: Number of steps per motor revolution, default is 200.
gear_ratio: float = 1400: The gear ratio of the motor, default is 1400.
angle_ratio: float = 540: The angle ratio for conversion, default is 540 (1.5 revolutions).
limits: dict = None: Position limits per axis, formatted as {axis_number: {“lo”: lower_limit, “hi”: upper_limit}}.
**kwargs: Additional parameters passed to VisaDevice: write_termination (default “), read_termination (default”), cmdpers (default 50), timeout (default 80000), baud_rate (default 2400).

Notes

To use a different unit system (e.g. linear positioning in mm instead of degrees), adjust steps_per_revolution, gear_ratio and angle_ratio to match your mechanical setup.

Methods

Name	Description
configure_drive()	Configure the drive settings for an axis.
get_moving()	Check if the specified axis is currently moving.
get_pos()	Get the current position of an axis.
id()	Get the device identification string.
initialize()	Initialize the axis and drive the stage to position 0.
move_abs()	Move to absolute position and block until position is reached.
move_abs_nonblocking()	Move to absolute position without blocking.
move_rel()	Move relative to current position and block until complete.
move_rel_nonblocking()	Move relative to current position without blocking.
stop()	Stop the motion of an axis immediately.

configure_drive()

Configure the drive settings for an axis.

Usage

Source

configure_drive(
    stepfreq,
    ramp,
    startfreq,
    ax=0,
)

Configures the parameters used by move_abs and move_rel. If drive/axis settings are not configured, device internal defaults are used.

Parameters

stepfreq: int: Step frequency in Hz. Maximum frequency is 15 kHz.
ramp: int: Ramp time in ms.
startfreq: int: Start frequency in Hz at the beginning of the ramp.
ax: int = 0: Axis to be configured (0-3), default is 0.

Notes

(stepfreq-startfreq)/ramp must be >= 100 Hz/s (watch units). For more details, refer to the device manual.

get_moving()

Check if the specified axis is currently moving.

Usage

Source

get_moving(ax=0)

Parameters

ax: int = 0: Axis to check (0-3), default is 0.

Returns

bool: True if the axis is moving, False otherwise.

get_pos()

Get the current position of an axis.

Usage

Source

get_pos(ax=0)

Parameters

ax: int = 0: Axis to query (0-3), default is 0.

Returns

float: Current position in units defined by _steps_per_deg.

id()

Get the device identification string.

Usage

Source

id()

Returns

str: The device ID string.

initialize()

Initialize the axis and drive the stage to position 0.

Usage

Source

initialize(ax=0)

MOTION STARTS IMMEDIATELY if the axis is not at zero position!

Parameters

ax: int = 0: Axis to be initialized (0-3), default is 0.

move_abs()

Move to absolute position and block until position is reached.

Usage

Source

move_abs(
    pos,
    ax=0,
)

Adjust the timeout for very long strides to ensure the function waits until the target position is reached.

Parameters

pos: float: Desired absolute position in units defined by _steps_per_deg.
ax: int = 0: Axis to move (0-3), default is 0.

Returns

None: Function returns silently if the position is outside the configured limits or if the motor is already moving.

move_abs_nonblocking()

Move to absolute position without blocking.

Usage

Source

move_abs_nonblocking(
    pos,
    ax=0,
)

Initiates a movement to the specified position and returns immediately, without waiting for the motion to complete.

Parameters

pos: float: Desired absolute position in units defined by _steps_per_deg.
ax: int = 0: Axis to move (0-3), default is 0.

Returns

None: Function returns silently if the position is outside the configured limits or if the motor is already moving.

move_rel()

Move relative to current position and block until complete.

Usage

Source

move_rel(
    pos,
    ax=0,
)

Adjust the timeout for very long strides to ensure the function waits until the target position is reached.

Parameters

pos: float: Desired relative position in units defined by _steps_per_deg.
ax: int = 0: Axis to move (0-3), default is 0.

Returns

None: Function returns silently if the movement would exceed limits or if the motor is already moving.

move_rel_nonblocking()

Move relative to current position without blocking.

Usage

Source

move_rel_nonblocking(
    pos,
    ax=0,
)

Initiates a relative movement and returns immediately, without waiting for the motion to complete.

Parameters

pos: float: Desired relative position in units defined by _steps_per_deg.
ax: int = 0: Axis to move (0-3), default is 0.

Returns

None: Function returns silently if the movement would exceed limits or if the motor is already moving.

stop()

Stop the motion of an axis immediately.

Usage

Source

stop(ax=0)

Parameters

ax: int = 0: Axis to stop (0-3), default is 0.