Source code for device.langmuir_probe

from types import SimpleNamespace

from . import base

import time




class LangmuirProbe(base.ArduinoProbeBase):
    """Arduino controller that handles a Langmuir probe (Langmuir probes).

    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__(bus=bus, start_msg="START lagmuir ventil", **kwargs)

        self._last = SimpleNamespace(
            valve_open=False,
            needle_percent=0.0,
        )

    # ==== Commands ====



    def is_valve_open(self):
        """Status of the valve."""
        return self._last.valve_open




    @base.base_command
    def set_needle(self, percent):
        """Change the state of the needle valve.

        :param float precent: Percentage in range 0-100, where 0 is closed.
        """
        percent = max(0.0, min(100.0, float(percent)))
        self._write(f"p{int(percent*255/100)}\n")
        self._last.needle_percent = percent
        self._last.valve_open = (percent != 0)
        return self._last.needle_percent




    @base.compound_command
    def set_needle_for(self, percent, duration):
        """Open needle valve for a limited duration ("gas puff").

        :param float percent: Percentage in range 0-100, where 0 is closed.
        :param float duration: Time in seconds.
        """
        self.set_needle(percent)
        time.sleep(max(0, float(duration)))
        self.set_needle(0)




    @base.base_command
    def open_valve(self):
        """Open the valve."""
        if not self._last.valve_open:
            self._write("p100\n")
            self._last.valve_open = True




    @base.base_command
    def close_valve(self):
        """Close the valve."""
        if self._last.valve_open:
            self._write("p0\n")
            self._last.valve_open = False