Source code for device.magnets_ps_switch

import serial
import time

from . import base




class PowerSupply_Magnets_SwitchOnOff(base.HardwareBase):
    """Mains power switch for 2 power suplies (magnets experiment).

    Communication:

        - Serial interface to Arduino, send 's' to toggle the switch.
    """
    def __init__(self, bus, **kwargs):
        super().__init__(**kwargs)

        self._busname = bus
        self._ardu = None

        self._last = {
            "switched_on": False
        }

    # ==== Inherited abstract methods ====
    def _connect(self):
        def reset(ardu):
            ardu.dtr = False
            time.sleep(0.1)
            ardu.reset_input_buffer()
            ardu.dtr = True

        try:
            self._ardu = serial.Serial(self._busname, 9600)
        except serial.SerialException:
            self.log.debug("Failed to open serial '%s'", self._busname)
            return False
        reset(self._ardu)
        self._ardu.timeout = 5
        # TODO Not even sure if it sends any hello message
        self._ardu.readline().strip().decode("ascii")

        self._last["switched_on"] = False
        return True

    def _disconnect(self):
        self.switch_off()
        self._ardu.close()
        self._ardu = None
        return

    def _is_ready(self):
        return True

    def _safestate(self):
        self.switch_off()

    # ==== Commands ====



    def is_on(self):
        return self._last["switched_on"]




    @base.base_command
    def switch_on(self):
        if not self._last["switched_on"]:
            self._ardu.write(b"s")
            self._last["switched_on"] = True




    @base.base_command
    def switch_off(self):
        if self._last["switched_on"]:
            self._ardu.write(b"s")
            self._last["switched_on"] = False