Source code for device.power_supply_langmuir

from types import SimpleNamespace

from . import base




class PowerSupply_Langmuir(base.ArduinoBase):
    """Arduino controller that handles a power supply that generates plasma
    in the Langmuir probes experiment.

    Communication:

    - serial interface to Arduino
    """

    def __init__(self, bus, **kwargs):
        """Constructor

        :param str bus: Name of serial bus where Arduino is connected,
                        e.g. '/dev/ttyUSB0'
        """
        super().__init__(
            serial_cfg=base.SerialConfig(bus, 9600, "START lagmuir VN zdroj"),
            **kwargs,
        )

        self._last = SimpleNamespace(
            switched_on=False,
            voltage=0,
            current=0,
            current_limit=0,
        )

    # ==== Commands ====



    @base.base_command
    def switch_on(self):
        self._write("0")
        # Arduino does not give any response
        self._last.switched_on = True




    @base.base_command
    def switch_off(self):
        self._write("0")
        # Arduino does not give any response
        self._last.switched_on = False




    @base.base_command
    def is_switched_on(self):
        return self._last.switched_on




    @base.base_command
    def voltage(self):
        """Return output voltage [V]."""
        self._write("u")
        self._last.voltage = float(self._readline())
        return self._last.voltage




    @base.base_command
    def current(self):
        """Return output current [mA]."""
        self._write("i")
        self._last.current = float(self._readline())
        return self._last.current




    @base.base_command
    def increment_max_current(self):
        """Increment max current by 1 step. Returns the value in %."""
        self._write("+")
        # Arduino responds with arbitrary 0-31 value
        self._last.current_limit = float(self._readline()) / 31 * 100
        return self._last.current_limit




    @base.base_command
    def decrement_max_current(self):
        """Decrement max current by 1 step. Returns the value in %."""
        self._write("-")
        # Arduino responds with arbitrary 0-31 value
        self._last.current_limit = float(self._readline()) / 31 * 100
        return self._last.current_limit


    # ==== Methods/commands related to DeviceClient ====

    @base.idle_command
    def _idle_update_all(self):
        # Call to each of these methods updates self._last
        self.voltage()
        self.current()



    def update_frontend(self, device_client):
        self._idle_update_all()
        for var, unit, max_ in zip(
            ["voltage", "current", "current_limit"],
            ["V", "mA", "%"],
            [900, 50, 100],
        ):
            value = getattr(self._last, var)
            device_client.emit("value", {
                "value": value,
                "formatted": "{:.0f} {}".format(value, unit),
                "label": var.capitalize().replace("_", " "),
                "min": 0,
                "max": max_,
                "id": var,
            })