My program's application falls in the Noise and Vibration's field. I am using Tri-Axial Accelerometers with the Sound & Vibrations Toolkit with the vi: SoundVib_Calibration.lvlib:SVL Calibrate Accelerometer (DAQmx).vi, and as soon as the AI Channel is selected, the -1926 Error comes up, which is related to the Not Detections of the Calibration Signal or, to the Frequency of the Calibration Signal out of range (tolerance); however, this is not the found conditions oo my equipment; I am using an Accelerometers Calibrator (PCB 394C06 – Accel: 1g, Freq.: 159.2 Hz, Max Load 210 gramsPCB 394C06 – Accel: 1g, Freq.: 159.2 Hz, Max Load 210 grams) and a CompactDAQ 9172 with 9234 modules, and while I try to calibrate every single axis, I make myself sure to keep the Calibrator on and all de modules detected as well... As I said, the error appears every time a new channel is selected (ensuring you have the signal on it ...), only once; But looking at the low level VIs, I found that the error is generated in the SoundVib_Calibration.lvlib: SVL Calibrate Sensor (DAQmx) .vi, and according to its Block Diagram, this error is related to having the signal frequency But this error also appears when there is no signal connected to the selected AI channel; So it seems that for some reason the low level vi can not detect the signal of the new channel selected, is how the vi continues to signal in the previous channel where there is no signal. Until it runs again (for the second time), the error goes away ... I have attached a file with some shot screens with more details on what I have done (interchanging the calibration signal, modules, etc.) for verifying the calibration signal is detected. As additional information, I am using the latest release of LabVIEW 2016 (32-bit) for Windows 7 Enterprise, the Sound & Vibration Toolkit 2016, and the laterst DAQmx Drivers.
Better late than never 🙂
If you haven't solved your issue by now, can you zoom on low frequency in your power spectra graphs. Difficult to see but it looks like you have either a big DC or tone at frequency lower than 159 Hz present when it fails.
Actually I am pretty sure you are having IEPE settling issues. The IEPE supply takes several seconds to settle (DC signal settling through your channel AC-coupling) and that happens every time you select/activate a new channel for the very first time after power on.
DAQmX Help says:
Changing the IEPE excitation level may cause transient voltages to appear in the signal. NI-DAQmx does not implement a delay to allow the signal to settle. Therefore, after changing the IEPE level and committing this change to the hardware with the Start function/VI or the Control Task function/VI, you might add a software delay to allow the signal to settle before proceeding with your application.
In your VI you are using a value for the time to settle parameter of 200 ms. Try 2 to 5 s (experiment with that value by looking at the exponential DC decay of your time domain waveform. A good target could be to have a DC offset at the beginning of your acquisition that is less than 10% of your 159 Hz tone amplitude)