Work with Devices
=================

.. note::

    Assuming you've followed the `quickstart guide <../index>` or otherwise got an IPython terminal to control a test rig...

There are objects provided that represent the hardware devices on the test rig, for example, the motors. The devices exist in a tree-like heirachy, 
so you can drill down into individual motors.

.. code:: IPython

    In [1]: sample_stage
    Out[1]: SampleStage(prefix='BL49P-MO-MAP-01:STAGE:', name='sample_stage', read_attrs=['x', 'x.user_readback', 'x.user_setpoint', 'theta', 'theta.user_readback', 'theta.user_setpoint'], configuration_attrs=['x', 'x.user_offset', 'x.user_offset_dir', 'x.velocity', 'x.acceleration', 'x.motor_egu', 'theta', 'theta.user_offset', 'theta.user_offset_dir', 'theta.velocity', 'theta.acceleration', 'theta.motor_egu'])

    In [2]: sample_stage.theta
    Out[2]: EpicsMotor(prefix='BL49P-MO-MAP-01:STAGE:A', name='sample_stage_theta', parent='sample_stage', settle_time=0.0, timeout=None, read_attrs=['user_readback', 'user_setpoint'], configuration_attrs=['user_offset', 'user_offset_dir', 'velocity', 'acceleration', 'motor_egu'])


You can call ``describe()`` on an Ophyd object to see what information can be recorded about it as beamline data.

.. code:: IPython

    In [3]: sample_stage.theta.describe()
    Out[3]: 
    OrderedDict([('sample_stage_theta',
                {'source': 'PV:BL49P-MO-MAP-01:STAGE:A.RBV',
                'dtype': 'number',
                'shape': [],
                'units': 'mm',
                'lower_ctrl_limit': 0.0,
                'upper_ctrl_limit': 0.0,
                'precision': 3}),
                ('sample_stage_theta_user_setpoint',
                {'source': 'PV:BL49P-MO-MAP-01:STAGE:A.VAL',
                'dtype': 'number',
                'shape': [],
                'units': 'mm',
                'lower_ctrl_limit': 0.0,
                'upper_ctrl_limit': 0.0,
                'precision': 3})])


There is a simple Bluesky plan for moving the motor:

.. code:: IPython

    In [4]: RE(bps.mv(sample_stage.theta, 0))
    Out[4]: ()

    In [5]: RE(bps.mv(sample_stage.theta, 360*5))
    Out[5]: ()


.. note:: ``RE`` refers to the Bluesky ``RunEngine``, which executes plans and does the actual talking to hardware.

While moving the motors, you can open the EDM synoptic and observe their behavoir in EPICS too (this is particularly useful for debugging). All 4 test rigs can be found in the Diamond launcher under Beamlines -> Lab IOCs.

``mv()`` can move multiple motors simultaneously too:

.. code:: IPython

    In [6]: RE(bps.mv(sample_stage.theta, -360*5, sample_stage.x, 0))
    Out[6]: ()