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waveform tester exercise
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Diff for: ‎.gitignore

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*-checkpoint.ipynb
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*.DS_Store

Diff for: ‎exercises/raster.png

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Diff for: ‎exercises/scan_waveform_output.py

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'''
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Exercise in which a DAQ board will generate hardware-timed continuous analog output from two
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channels without using a callback function
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scan_waveform_output
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Purpose
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You will do hardware-timed continuous analog output using sample regeneration instead of a callback function.
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The buffer contents is played out repeatedly: once the end of the buffer is reached, the DAQ returns to the
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beginning and resumes from there.
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Monitoring the output
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If you lack an oscilloscope you may physically connect the analog output to
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an analog input and monitor this using the NI MAX test panel. You likely will need
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to select RSE: http://www.ni.com/white-paper/3344/en/
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Ask MAX to display "AI0:1"
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Instructions
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- Wire AO0 to AO0 or to an osciloscope. Wire AO1 to AO1 or to an osciloscope.
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- You will need to edit the lines at the locations marked by the string ### EDIT
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- There may be hints and instructions around those lines
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Run the code at the command line thus:
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python scan_waveform_output
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For more:
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https://github.com/tenss/Python_DAQmx_examples
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'''
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import nidaqmx
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from nidaqmx.constants import (AcquisitionType,RegenerationMode)
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import numpy as np
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class scan_waveform_output():
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# Properties of the class defined here
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# Parameters for the acquisition (device and channels)
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dev_name = '' ### EDIT (The name of the DAQ device as shown in MAX)
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# Task configuration
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sample_rate = 5000 # Sample Rate in Hz
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galvo_amplitude = 5 # Scanner amplitude (defined as peak-to-peak/2)
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pixels_per_line = 256 # Number pixels per line for a sawtooth waveform (for sine wave this defines wavelength)
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x_waveform = [] # Vector containing the waveform for the x mirror (fast axis)
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y_waveform = [] # Vector containing the waveform for the y mirror (slow axis)
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daq_waveforms = [] # Will contain the x and y waveform data to be sent to the DAQ
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num_samples_per_channel = [] #The length of the waveform
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h_task = [] # DAQmx task handle
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def __init__(self, autoconnect=False):
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# This method is the constructor and runs once when the class is instantiated
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self.generate_waveforms()
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if autoconnect:
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self.create_task()
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#close constructor
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def generate_waveforms(self):
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###EDIT -- complete this method
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self.y_waveform =
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self.x_waveform =
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# This must be a two column matrix. The first column is the waveform sent to AO0
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# and the second column is the waveform sent to AO1.
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self.daq_waveforms = np.stack() ###EDIT
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#close generate_waveforms
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def create_task(self):
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# This method sets up an NI Task that will play out the waveforms
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# * Create a DAQmx task
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# http://zone.ni.com/reference/en-XX/help/370471AE-01/daqmxcfunc/daqmxcreatetask/
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self.h_task = nidaqmx.Task('scanwave')
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# * Set up analog output on channels 0 and 1
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# C equivalent - DAQmxCreateAOVoltageChan
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# http://zone.ni.com/reference/en-XX/help/370471AE-01/daqmxcfunc/daqmxcreateaovoltagechan/
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# https://nidaqmx-python.readthedocs.io/en/latest/ao_channel_collection.html
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connect_at = '%s/ao0:1' % self.dev_name
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self.h_task.ao_channels.add_ao_voltage_chan(connect_at)
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# * Configure the sampling rate and the number of samples
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# C equivalent - DAQmxCfgSampClkTiming
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# http://zone.ni.com/reference/en-XX/help/370471AE-01/daqmxcfunc/daqmxcfgsampclktiming/
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# https://nidaqmx-python.readthedocs.io/en/latest/timing.html
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self.num_samples_per_channel = len(self.waveform) # The number of samples to be stored in the buffer per channel
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buffer_length = self.num_samples_per_channel*4 # TODO -- IS THIS NEEDED??
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self.h_task.timing.cfg_samp_clk_timing(rate = self.sample_rate, \
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samps_per_chan = buffer_length, \
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sample_mode = AcquisitionType.CONTINUOUS)
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# * Set up sample regeneration: i.e. the buffer contents will play continuously
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# http://zone.ni.com/reference/en-XX/help/370471AE-01/mxcprop/attr1453/
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# For more on DAQmx write properties: http://zone.ni.com/reference/en-XX/help/370469AG-01/daqmxprop/daqmxwrite/
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# For a discussion on regeneration mode in the context of analog output tasks see:
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# https://forums.ni.com/t5/Multifunction-DAQ/Continuous-write-analog-voltage-NI-cDAQ-9178-with-callbacks/td-p/4036271
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self.h_task.out_stream.regen_mode = RegenerationMode.ALLOW_REGENERATION
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print('Regeneration mode is set to: %s' % str(self.h_task.out_stream.regen_mode))
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# * Write the waveform to the buffer with a 5 second timeout in case it fails
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# Writes doubles using DAQmxWriteAnalogF64
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# http://zone.ni.com/reference/en-XX/help/370471AG-01/daqmxcfunc/daqmxwriteanalogf64/
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self.h_task.write(, timeout=2). ###EDIT
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#close create_task
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#close class scan_waveform_output
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if __name__ == '__main__':
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print('\nRunning demo for hardwareContinuousVoltageNoCallback_twoChannels\n\n')
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AO = hardwareContinuousVoltageNoCallback_twoChannels()
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AO.create_task()
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AO.h_task.start()
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input('press return to stop')
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AO.h_task.start()

Diff for: ‎exercises/scanwaveforms.ipynb

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{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"[](raster.png)"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"In this exercise you will generate scanner X/Y waveforms capable of producing a raster pattern that moves the beam in shape over the image:\n",
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"![alt text](raster.png \"Title\")\n",
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"The goal is to generate waveforms that will produce a square image: one where the number of pixels per line equals the number of lines. Note carefully the shape of the waveform: the beam scans across each line in the same direction. "
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]
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},
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{
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"cell_type": "code",
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"execution_count": 4,
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"metadata": {},
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"outputs": [],
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"source": [
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"import numpy as np\n",
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"import matplotlib.pyplot as plt"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {},
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"outputs": [],
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"source": [
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"# You will use the following two constants to help you build the waveforms. \n",
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"imsize = 128. # target image size in pixels (imsize x imsize)\n",
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"scan_amplitude = 2 # The scanners will move between -scan_amplitude and +scan_amplitude"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"# Over the course of one frame the slow (y) scanner will move from one \n",
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"# extreme of the amplitude range to the other to the other once. \n",
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"# The number of pixels (samples) it takes to do this will be equal to \n",
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"# the total number of pixels in the frame.\n",
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"#\n",
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"# In one line of code, define the y waveform. (HINT: linspace)\n",
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"\n",
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"y_waveform = \n"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"# The x mirror will move over the amplitude range once per line. \n",
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"#\n",
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"# In one line of code, define the x waveform for one scan line.\n",
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"# HINT: it's almost the same as what you did for y_waveform.\n",
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"one_scan_line = \n",
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"\n",
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"# Use the vector you created to generate the complete x waveform\n",
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"# for one frame. Think how many times you have to repeat the waveform\n",
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"x_waveform =\n"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## Run the following cells to check your working"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"# Y waveform\n",
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"plt.plot(y_waveform)\n",
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"plt.title('y waveform')\n",
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"plt.ylabel('voltage')\n",
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"plt.show()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"# X waveform\n",
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"plt.plot(x_waveform)\n",
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"plt.title('x waveform')\n",
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"plt.ylabel('voltage')\n",
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"plt.xlabel('# samples')\n",
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"plt.show()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": [
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"# The raster waveform\n",
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"plt.plot(x_waveform,y_waveform)\n",
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"plt.axis('equal')\n",
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"plt.axis('off')\n",
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"plt.show()\n",
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"\n",
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"print('X waveform length: %d\\nY waveform length: %d\\nLength of scan line in samples: %d\\n' % \\\n",
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" (len(y_waveform), len(x_waveform), len(one_scan_line)) )\n"
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]
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.7.4"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 4
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}

Diff for: ‎src/scanwaveforms.ipynb

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"plt.title('x waveform')\n",
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"plt.ylabel('voltage')\n",
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"plt.xlabel('# samples')\n",
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"plt.show()\n",
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"\n",
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"plt.plot(x_waveform,y_waveform_stepped)\n",
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"plt.ylabel('voltage')\n",
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"plt.xlabel('# samples')\n",
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"plt.axis('equal')\n",
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"plt.axis('off')\n",
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"plt.show()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": []
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}
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],
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"metadata": {
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.8.3"
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"version": "3.7.4"
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}
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},
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"nbformat": 4,

Diff for: ‎src/waveformTester.py

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return LP
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#close line_period
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#close class waveformTester()
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#close class waveformTester
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