Two channel scan using single task Daqmx with multiple output signals

[ljc19800331]

Hello, 

I am using NI-USB-6211 DAQ to control the X-Y Galvanometers and I want to input multiple angle signals. The code only move to one position and stop. I am not sure if this is the problem with my code and are there any ways to check the problems? Thanks. 

import numpy as np
from PyDAQmx import *
import PyDAQmx

class Galvo:

    def __init__(self):

        print("initialized Galvo")

        # State variables
        self.x_mirror_volt = [0.0]    # Initialize to origin
        self.y_mirror_volt = [0.0]
        self.writeFrequency = 120000.

        # Initialize the Galvo setting
        self.Galvo_MoveTask = Task()
        self.Galvo_MoveTask.CreateAOVoltageChan("Dev1/ao0", "X_Out", -10., 10., DAQmx_Val_Volts, None)
        self.Galvo_MoveTask.CreateAOVoltageChan("Dev1/ao1", "Y_Out", -10., 10., DAQmx_Val_Volts, None)
        data_init = np.array(np.append(self.x_mirror_volt, self.y_mirror_volt), dtype = np.float64)         # Initial the data with the (0.0, 0.0) pulses
        self.Galvo_MoveTask.WriteAnalogF64(1, 1, -1, DAQmx_Val_GroupByChannel, data_init, None, None)

    def raster_region(self, x_volt, y_volt):

        # taskHandle.WriteAnalogF64(number of samples per channel, automatically start task,
        #                           seconds before timeout (-1 means don't timeout), grouping of samples
        #                            (by channel or by scan), data array, array size,
        #                           number of samples actually read, None)
        data = np.array(np.append(x_volt, y_volt), dtype = float64)

        self.Galvo_MoveTask.CfgSampClkTiming(None, self.writeFrequency, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps, np.size(x_volt))
        self.Galvo_MoveTask.WriteAnalogF64(np.size(x_volt), 1, 10, DAQmx_Val_GroupByChannel, data, None, None)
        self.Galvo_MoveTask.WaitUntilTaskDone(-1)
        self.Galvo_MoveTask.StopTask()
        self.Galvo_MoveTask.ClearTask()

if __name__ == "__main__":

    test = Galvo()

    x_volt = [0.5, 1.0, 1.5]
    y_volt = [1.5, 0.5, 1.5]
    print(x_volt)
    print(y_volt)
    test.raster_region(x_volt, y_volt)