.. currentmodule:: omc048
.. _omc048.voltage_ref:


class Voltage Reference
=======================

Control the voltage reference output to generate a reference voltage on the given hardware port.

.. attention::
    Attention the analog reference voltage on all  OMC-048 loggers with **BL: 1.03B0** and upwards will be 5V! All other OMC-048 loggers got a 2.5V reference voltage.
    
Constructor
-----------

.. class:: omc048.voltage_ref(id: integer)

   Create a voltage reference object associated with a voltage reference hardware port.

   - ``id`` is the voltage reference hardware number, on the OMC-048  the "id" is "1" corresponding to pin 17.


Methods
-------

.. method:: voltage_ref.set(state: integer)
   
   Set the reference output on or off.

   - ``state`` is 1 or 0, corresponding to on and off.

.. method:: voltage_ref.on()

   Enable reference output to the port.

.. method:: voltage_ref.off()

   Disable reference output to the port.

.. method:: voltage_ref.toggle()

   Switch the reference output state from the current to the other state. 
   Turning it on when it was off and off when it was on.


Example
-------

The following example enables the reference output (generating 2.5V as a reference), then turns the reference off after 5 seconds.
Then again after 5 seconds the reference is toggled, which sets the reference output on again. ::

    import omc048
    import time
    
    ref1 = omc048.voltage_ref(1)

    ref1.on()

    time.sleep(5)
    ref1.off()
    time.sleep(5)
    ref1.toggle()