Adding Basic Arb Sequence Example in NI-FGEN

CHANGELOG.md

@@ -1123,6 +1123,7 @@
 
 #### [nifgen] Unreleased
 - Added
+  - Added the `nifgen_basic_arb_sequence.py` example.
   - (Common) Added `nitlsconfig[grpc]>=1.0.0a2` to the optional gRPC dependencies.
 - Changed
 - Removed

docs/nifgen/examples.rst

@@ -12,6 +12,15 @@ nifgen_arb_waveform.py
    :encoding: utf8
    :caption: `(nifgen_arb_waveform.py) <https://github.com/ni/nimi-python/blob/master/src/nifgen/examples/nifgen_arb_waveform.py>`_
 
+nifgen_basic_arb_sequence.py
+----------------------------
+
+.. literalinclude:: ../../src/nifgen/examples/nifgen_basic_arb_sequence.py
+   :language: python
+   :linenos:
+   :encoding: utf8
+   :caption: `(nifgen_basic_arb_sequence.py) <https://github.com/ni/nimi-python/blob/master/src/nifgen/examples/nifgen_basic_arb_sequence.py>`_
+
 nifgen_script.py
 ----------------
 

src/nifgen/examples/nifgen_basic_arb_sequence.py

@@ -0,0 +1,80 @@
+#!/usr/bin/python
+
+import argparse
+import math
+import nifgen
+import numpy
+import sys
+import time
+
+# Each shape returns a value between -1.0 and +1.0 for a position x in [0, 1) of one cycle.
+WAVEFORM_SHAPES = {
+    'SINE': lambda x: math.sin(2 * math.pi * x),
+    'SQUARE': lambda x: 1.0 if x < 0.5 else -1.0,
+    'TRIANGLE': lambda x: 1 - 4 * abs(x - 0.5),
+    'DECREASING': lambda x: 1 - 2 * x,
+}
+
+# Waveform Information Array: (Waveform Type, Amplitude, # of points), generated in this order.
+DEFAULT_WAVEFORMS = [
+    ('SINE', 0.75, 256),
+    ('TRIANGLE', 1.0, 256),
+    ('SQUARE', 0.5, 256),
+    ('DECREASING', 0.8, 256),
+]
+
+
+def create_waveform_data(waveform_type, amplitude, number_of_points):
+    if not math.isfinite(amplitude) or not -1.0 <= amplitude <= 1.0:
+        raise ValueError('Amplitude must be finite and between -1.0 and 1.0.')
+    shape = WAVEFORM_SHAPES[waveform_type]
+    waveform_data = [round(32767 * amplitude * shape(i / number_of_points)) for i in range(number_of_points)]
+    return numpy.array(waveform_data, dtype=numpy.int16)
+
+
+def example(resource_name, options, waveforms, gain, offset, gen_time):
+    with nifgen.Session(resource_name=resource_name, options=options, channel_name='0') as session:
+        session.output_mode = nifgen.OutputMode.SEQ
+        waveform_handles = [session.create_waveform(waveform_data_array=create_waveform_data(*waveform)) for waveform in waveforms]
+        loop_counts = [1] * len(waveform_handles)
+        sequence_handle = session.create_arb_sequence(waveform_handles_array=waveform_handles, loop_counts_array=loop_counts)
+        session.configure_arb_sequence(sequence_handle=sequence_handle, gain=gain, offset=offset)
+        with session.initiate():
+            print('Generating sequence for {} seconds:'.format(gen_time))
+            for waveform_type, amplitude, number_of_points in waveforms:
+                print('  {:<10} amplitude {:<5} {} points'.format(waveform_type, amplitude, number_of_points))
+            time.sleep(gen_time)
+
+
+def _main(argsv):
+    parser = argparse.ArgumentParser(description='Continuously generates an arbitrary sequence of 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('-w', '--waveform', nargs=3, action='append', metavar=('TYPE', 'AMPLITUDE', 'POINTS'), help='Sequence entry: type, normalized peak amplitude (-1 to 1), and point count. Repeat in output order; supplied entries replace the defaults. Types: {}. Default sequence: {}'.format(', '.join(WAVEFORM_SHAPES), ', '.join('{} {} {}'.format(*waveform) for waveform in DEFAULT_WAVEFORMS)))
+    parser.add_argument('-g', '--gain', default=1.0, type=float, help='Gain')
+    parser.add_argument('-o', '--offset', default=0.0, type=float, help='DC offset (V)')
+    parser.add_argument('-t', '--time', default=5.0, type=float, help='Generation time (s)')
+    parser.add_argument('-op', '--option-string', default='', type=str, help='Option string')
+    args = parser.parse_args(argsv)
+    waveforms = [(w_type.upper(), float(amplitude), int(points)) for w_type, amplitude, points in args.waveform or DEFAULT_WAVEFORMS]
+    for waveform_type, _, _ in waveforms:
+        if waveform_type not in WAVEFORM_SHAPES:
+            parser.error('Unsupported waveform type {}. Choose from {}.'.format(waveform_type, ', '.join(WAVEFORM_SHAPES)))
+    example(args.resource_name, args.option_string, waveforms, args.gain, args.offset, args.time)
+
+
+def main():
+    _main(sys.argv[1:])
+
+
+def test_example():
+    options = {'simulate': True, 'driver_setup': {'Model': '5433 (2CH)', 'BoardType': 'PXIe', }, }
+    example('PXI1Slot2', options, DEFAULT_WAVEFORMS, 1.0, 0.0, 5.0)
+
+
+def test_main():
+    cmd_line = ['--option-string', 'Simulate=1, DriverSetup=Model:5433 (2CH);BoardType:PXIe', ]
+    _main(cmd_line)
+
+
+if __name__ == '__main__':
+    main()