x_sweep.py

import logging
import numpy as np
from time import sleep


from pymeasure.experiment import Procedure, IntegerParameter, FloatParameter

from ..classes.stage import Stage
from ..classes.dac import DAC

log = logging.getLogger(__name__)
log.addHandler(logging.NullHandler())

class X_Sweep(Procedure):
    name = "X-Sweep"
    acq_time = FloatParameter('Aquisition time', units='s', default=1)
    freq = FloatParameter('Aquisition Frequency', units='Hz', default=50)
    x_min = FloatParameter('From x', units='mm', default=0)
    x_max = FloatParameter('To x', units='mm', default=5)
    x_step = FloatParameter('Step', units='mm', default=0.1)
    y = FloatParameter('Position y', units='mm', default=0)
    field = FloatParameter('Magnetic field', units='V', default=0)

    DATA_COLUMNS = ['Iteration', 'X Position', 'Y Position', 'Voltage', 'Magnetic Field [A]', 'Magnetic Field [mT]']

    def startup(self):
        log.info("Setting up the data aquisition")

    def execute(self):
        log.info("Starting the voltage acquisition")

        voltage = DAC("ai0")
        field   = DAC("ao1")        

        x_positions = np.linspace(self.x_min, self.x_max, int((self.x_max-self.x_min)//self.x_step+1), endpoint=True)

        field.write(self.field)

        sleep(1)

        try:
            stage = Stage()
            stage.enable_connections()
        except:
            log.info("Close connection with motors before running an experiment, motors can not be used")

        stage.move_y_to(self.y)
        stage.move_x_to(self.x_min)
        stage.wait_stable()

        # Start sweeping loop
        for i in range(len(x_positions)):
            stage.move_x_to(x_positions[i])

            average_voltage = np.arange(0, int(round(self.acq_time * self.freq)), dtype='float64')

            for step in range(len(average_voltage)):
                average_voltage[step] = voltage.read()
                sleep(1/self.freq)
            data = {
                'Iteration': i,
                'X Position': x_positions[i],
                'Voltage': np.mean(average_voltage)
            }

            log.debug("Produced numbers: %s" % data)
            self.emit('results', data)
            self.emit('progress', 100 * i / len(x_positions))
            if self.should_stop():
                break

        field.write(0.)
        stage.close_connections()

    def shutdown(self):
        log.info("Finished acquisition")