Source code for instruments.keithley.keithley6220

#!/usr/bin/env python
"""
Provides support for the Keithley 6220 constant current supply
"""

# IMPORTS #####################################################################


from instruments.units import ureg as u

from instruments.abstract_instruments import PowerSupply
from instruments.generic_scpi import SCPIInstrument
from instruments.util_fns import bounded_unitful_property

# CLASSES #####################################################################




class Keithley6220(SCPIInstrument, PowerSupply):
    """
    The Keithley 6220 is a single channel constant current supply.

    Because this is a constant current supply, most features that a regular
    power supply have are not present on the 6220.

    Example usage:

    >>> import instruments.units as u
    >>> import instruments as ik
    >>> ccs = ik.keithley.Keithley6220.open_gpibusb("/dev/ttyUSB0", 10)
    >>> ccs.current = 10 * u.milliamp # Sets current to 10mA
    >>> ccs.disable() # Turns off the output and sets the current to 0A
    """

    # PROPERTIES ##

    @property
    def channel(self):
        """
        For most power supplies, this would return a channel specific object.
        However, the 6220 only has a single channel, so this function simply
        returns a tuple containing itself. This is for compatibility reasons
        if a multichannel supply is replaced with the single-channel 6220.

        For example, the following commands are the same and both set the
        current to 10mA:

        >>> ccs.channel[0].current = 0.01
        >>> ccs.current = 0.01
        """
        return (self,)

    @property
    def voltage(self):
        """
        This property is not supported by the Keithley 6220.
        """
        raise NotImplementedError(
            "The Keithley 6220 does not support voltage " "settings."
        )

    @voltage.setter
    def voltage(self, newval):
        raise NotImplementedError(
            "The Keithley 6220 does not support voltage " "settings."
        )

    current, current_min, current_max = bounded_unitful_property(
        "SOUR:CURR",
        u.amp,
        valid_range=(-105 * u.milliamp, +105 * u.milliamp),
        doc="""
        Gets/sets the output current of the source. Value must be between
        -105mA and +105mA.

        :units: As specified, or assumed to be :math:`\\text{A}` otherwise.
        :type: `float` or `~pint.Quantity`
        """,
    )

    # METHODS #



    def disable(self):
        """
        Set the output current to zero and disable the output.
        """
        self.sendcmd("SOUR:CLE:IMM")