nifgen_script.py

#!/usr/bin/python

import argparse
import nifgen

import math
import sys
import time

# waveform size should be a multiple of the quantum, which is 4, 2 or 1, for all devices
# minimum waveform size needed to prevent underflow varies with sample rate and device.
# If underflow occurs, increase this value.
NUMBER_OF_SAMPLES = 2096


# waveforms finish just short of 360 degrees, so that we don't repeat the first point
# if we repeat the waveform
SINE_WAVE = [math.sin(math.pi * 2 * x / (NUMBER_OF_SAMPLES)) for x in range(NUMBER_OF_SAMPLES)]
RAMP_UP = [x / (NUMBER_OF_SAMPLES) for x in range(NUMBER_OF_SAMPLES)]
RAMP_DOWN = [-1.0 * x for x in RAMP_UP]
SQUARE_WAVE = [1.0 if x < (NUMBER_OF_SAMPLES / 2) else -1.0 for x in range(NUMBER_OF_SAMPLES)]
SAWTOOTH_WAVE = RAMP_UP[::2] + [(-1 + x) for x in RAMP_UP][::2]


SCRIPT_ALL = '''
script scriptmulti
  repeat until scriptTrigger0
    generate rampup
    generate sine
    generate rampdown
  end repeat
  repeat until scriptTrigger0
    generate rampdown
    generate square
    generate rampup
  end repeat
  repeat until scriptTrigger0
    generate rampup
    generate rampdown
  end repeat
  repeat until scriptTrigger0
    generate sine
  end repeat
  repeat until scriptTrigger0
    generate sawtooth
  end repeat
  repeat until scriptTrigger0
    generate rampdown
    generate rampup
  end repeat
end script

script scriptsine
  repeat until scriptTrigger0
    generate sine
  end repeat
end script

script scriptrampup
  repeat until scriptTrigger0
    generate rampup
  end repeat
end script

script scriptrampdown
  repeat until scriptTrigger0
    generate rampdown
  end repeat
end script

script scriptsquare
  repeat until scriptTrigger0
    generate square
  end repeat
end script

script scriptsawtooth
  repeat until scriptTrigger0
    generate sawtooth
  end repeat
end script
'''


def example(resource_name, options, shape, channel):
    with nifgen.Session(resource_name=resource_name, options=options, channel_name=channel) as session:
        # CONFIGURATION
        # 1 - Set the mode to Script
        session.output_mode = nifgen.OutputMode.SCRIPT

        # 2 - Configure Trigger:
        # SOFTWARE TRIGGER: used in the script
        session.script_triggers[0].script_trigger_type = nifgen.ScriptTriggerType.SOFTWARE_EDGE  # TRIG_NONE / DIGITAL_EDGE / DIGITAL_LEVEL / SOFTWARE_EDGE
        session.script_triggers[0].digital_edge_script_trigger_edge = nifgen.ScriptTriggerDigitalEdgeEdge.RISING  # RISING / FAILING

        # 3 - Calculate and write different waveform data to the device's onboard memory
        session.channels[channel].write_waveform('sine', SINE_WAVE)        # (waveform_name, data)
        session.channels[channel].write_waveform('rampup', RAMP_UP)
        session.channels[channel].write_waveform('rampdown', RAMP_DOWN)
        session.channels[channel].write_waveform('square', SQUARE_WAVE)
        session.channels[channel].write_waveform('sawtooth', SAWTOOTH_WAVE)

        # 4 - Script to generate
        # supported shapes: SINE / SQUARE / SAWTOOTH / RAMPUP / RAMPDOWN / MULTI
        script_name = f'script{shape.lower()}'
        num_triggers = 6 if shape.upper() == 'MULTI' else 1  # Only multi needs multiple triggers, all others need one

        session.channels[channel].write_script(SCRIPT_ALL)
        session.script_to_generate = script_name

        # LAUNCH
        with session.initiate():
            for x in range(num_triggers):
                time.sleep(10)
                session.script_triggers[0].send_software_edge_trigger()


def _main(argsv):
    parser = argparse.ArgumentParser(description='Generate different shape waveforms.', formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    parser.add_argument('-n', '--resource-name', default='PXI1Slot2', help='Resource name of an NI arbitrary waveform generator.')
    parser.add_argument('-s', '--shape', default='SINE', help='Shape of the signal to generate')
    parser.add_argument('-c', '--channel', default='0', help='Channel to use when generating')
    parser.add_argument('-op', '--option-string', default='', type=str, help='Option string')
    args = parser.parse_args(argsv)
    example(args.resource_name, args.option_string, args.shape.upper(), args.channel)


def test_example():
    options = {'simulate': True, 'driver_setup': {'Model': '5433 (2CH)', 'BoardType': 'PXIe', }, }
    example('PXI1Slot2', options, 'SINE', '0')


def test_main():
    cmd_line = ['--option-string', 'Simulate=1, DriverSetup=Model:5433 (2CH);BoardType:PXIe', '--channel', '0', ]
    _main(cmd_line)


def main():
    _main(sys.argv[1:])


if __name__ == '__main__':
    main()