Adding Measure Capacitance example in NI-DMM

CHANGELOG.md

@@ -799,6 +799,7 @@
 #### [nidmm] Unreleased
 - Added
   - Added the `nidmm_measure_ac_volts.py` example.
+  - Added the `nidmm_measure_capacitance.py` example.
   - (Common) Added `nitlsconfig[grpc]>=1.0.0a2` to the optional gRPC dependencies.
 - Changed
 - Removed

docs/nidmm/examples.rst

@@ -21,6 +21,15 @@ nidmm_measure_ac_volts.py
    :encoding: utf8
    :caption: `(nidmm_measure_ac_volts.py) <https://github.com/ni/nimi-python/blob/master/src/nidmm/examples/nidmm_measure_ac_volts.py>`_
 
+nidmm_measure_capacitance.py
+----------------------------
+
+.. literalinclude:: ../../src/nidmm/examples/nidmm_measure_capacitance.py
+   :language: python
+   :linenos:
+   :encoding: utf8
+   :caption: `(nidmm_measure_capacitance.py) <https://github.com/ni/nimi-python/blob/master/src/nidmm/examples/nidmm_measure_capacitance.py>`_
+
 nidmm_measurement.py
 --------------------
 

src/nidmm/examples/nidmm_measure_capacitance.py

@@ -0,0 +1,57 @@
+#!/usr/bin/python
+
+import argparse
+import math
+import nidmm
+import re
+import sys
+
+# Only these models support capacitance measurements.
+SUPPORTED_MODELS = ('4072', '4082')
+
+
+def example(resource_name, options, function, range, measurements_to_average):
+    with nidmm.Session(resource_name=resource_name, options=options) as session:
+        model_match = re.search('[0-9]+', session.instrument_model)
+        model = model_match.group() if model_match else ''
+        if model not in SUPPORTED_MODELS:
+            print(f'{session.instrument_model} does not support capacitance measurements.\r\nSupported models: NI {", NI ".join(SUPPORTED_MODELS)}.')
+            return
+        # Resolution is ignored for capacitance and inductance, but the driver still validates it (3.5, 4.5, 5.5 or 6.5).
+        session.configure_measurement_digits(measurement_function=nidmm.Function[function], range=range, resolution_digits=5.5)
+        session.lc_number_meas_to_average = measurements_to_average
+        measurement = session.read()
+        # NI-DMM reports an underrange condition as negative infinity.
+        under_range = math.isinf(measurement) and measurement < 0
+        print(f'Measurement (Farads): {measurement}')
+        print(f'Signal Under Range: {under_range}')
+
+
+def _main(argsv):
+    supported_functions = list(nidmm.Function.__members__.keys())
+    parser = argparse.ArgumentParser(description='Performs a single capacitance measurement using the NI-DMM API (NI 4072/4082 only).', formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    parser.add_argument('-n', '--resource-name', default='PXI1Slot2', help='Contains the resource_name of the device to initialize.')
+    parser.add_argument('-f', '--function', default='CAPACITANCE', choices=supported_functions, type=str.upper, help='Specifies the measurement_function used to acquire the measurement.')
+    parser.add_argument('-r', '--range', default=3e-10, type=float, help='Specifies the range for the function specified in the Measurement_Function parameter.')
+    parser.add_argument('-a', '--measurements-to-average', default=1, type=int, help='For the NI 4072 only, specifies the number of LC measurements that are averaged to produce one reading.')
+    parser.add_argument('-op', '--option-string', default='', type=str, help='Sets the initial value of certain attributes for the session.')
+    args = parser.parse_args(argsv)
+    example(args.resource_name, args.option_string, args.function, args.range, args.measurements_to_average)
+
+
+def main():
+    _main(sys.argv[1:])
+
+
+def test_example():
+    options = {'simulate': True, 'driver_setup': {'Model': '4082', 'BoardType': 'PXIe', }, }
+    example('PXI1Slot2', options, 'CAPACITANCE', 3e-10, 1)
+
+
+def test_main():
+    cmd_line = ['--option-string', 'Simulate=1, DriverSetup=Model:4082; BoardType:PXIe', ]
+    _main(cmd_line)
+
+
+if __name__ == '__main__':
+    main()