# devices.owis:SMS


OWIS SMS motor controller class for stepper motor control.


Usage

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

------------------------------------------------------------------------


### configure_drive()


Configure the drive settings for an axis.


Usage

``` python
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

``` python
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

``` python
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

``` python
id()
```


#### Returns


`str`  
The device ID string.


------------------------------------------------------------------------


### initialize()


Initialize the axis and drive the stage to position 0.


Usage

``` python
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

``` python
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

``` python
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

``` python
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

``` python
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

``` python
stop(ax=0)
```


#### Parameters


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