With autonomous position sweeping, the measurement initiation is triggered by the positioner instead of the test execution engine. This mode drastically reduces test time.
The motor control sends a digital trigger that causes the instrumentation to execute the measurement at predefined points in the motion path. The measurement results and absolute coordinates of the positioner are stored in a table to link each measurement with its exact position later during results processing. During autonomous position sweeping, motion is supervised by the test execution engine while all the measurements happen in a separate autonomous thread driven by hardware signals.
Use autonomous sweeping when your main task is to get a large number of power measurements around the sphere in a single configuration. This means validating a specific codebook item, frequency, or polarization.
Complete the following actions before getting started with autonomous position sweeping.
Verify that the hardware connections are configured as specified in Verifying Hardware Connections.
- Remove the laser alignment fixture.
- Use the mmWave OTA Test Positioner SFP to verify that your DUT can move in all directions without collision.
- Configure TestStand to include the following search paths, including subdirectories, in the search directories:
C:\Program Files\National Instruments\LabVIEW 2018\user.lib\OTA Test
C:\Program Files\National Instruments\LabVIEW 2018\instr.lib
C:\Program Files\National Instruments\LabVIEW 2018\vi.lib\RFmx
- Configure TestStand to call LabVIEW Development System (64-bit).
Autonomous mode uses PXI trigger lines between the PXIe-6361 and PXIe-5831. Route the following trigger routes in MAX:
The PXIe-6361 appears as DAQ in MAX.
PXI_Trig0 from the PXIe-6361 bus segment to the PXIe-5831 bus segment
PXI_Trig1 from the PXIe-5831 bus segment to the PXIe-6361 bus segment
Complete the following steps to perform a full antenna pattern test in autonomous mode.
Navigate to C:\Users\Public\Public Documents\National Instruments\TestStand 2019 (64-bit)\Examples\OTA Test\Sequences and open the CSV settings file, Autonomous_TRP.csv.
Verify that the individual modules are named correctly in MAX. If the names do not match, either change the name in MAX to match the file or change the file to match your MAX settings.
Open the Autonomous_TRP.seq TestStand sequence, located at C:\Users\Public\Public Documents\National Instruments\TestStand 2019 (64-bit)\Examples\OTA Test\Sequences.
Run the sequence.
The sequence runs for about 30 seconds collecting data at 2° intervals elevation and 5° intervals azimuth.
Verify that nothing interferes with the motion of the positioner. The sequence triggers motion which may cause damage if anything interferes with the positioner.
Use the mmWave OTA Test Visualizer to visualize the data in the CSV file that is created in the Results folder, located in the same directory as the Sequences folder.
Your system is fully operational if the sequence finishes without error and you can display a 3D antenna pattern from the antenna. To verify the accuracy of the test, refer to Performing System Calibration.
NI recommends familiarizing yourself with the example sequences. When you save the example sequence as a new file, you must also save the CSV file with the same file name so the sequence file can load it correctly.