Real-Time Measurement and Control

Showing results for 
Search instead for 
Did you mean: 

Process data using NI 9223 and Switch off IEPE in 9234 with Compact RIO


I am running a test rig composed of rotating bladed disk and a contactless sensor (Eddy current sensor) attached to a casing around the rotating blades to acquire the time of the passing of the blades past the sensor (see Figure 1 attached). I am using a cRIO 9039 with an NI 9223 and an NI 9234 to acquire the voltage output from the sensor. First I tried with the NI 9223 using a Real time code but I was not able to obtain clean data only by acquiring a raw data, but Using the NI 9234 I was able to obtain a clean data and I think this is due to the anti-aliasing filter included in the NI 9234. The first Issue I want to know is what can I do or add to my code to get a clean data using the NI 9223? (I have attached the project and the VI file I am using).
The second issue is that using the NI 9234 there is some periodic peaks are showing between the main peaks that I was not able to identify the cause of it? to more understand the issue I have attached a figure 2 that show the signal collected using DataPhysics hardware where it shows a clean data composed of multiple peaks corresponding to the passage of each blade pass the sensor. Figure 3a shows the signal collected by the NI hardware when the blades are static and Figure 3b shows the signal at speed =100 rpm of the blades. You can see the small peaks show up between the main peaks. I was doubting maybe they are caused by the IEPE (2mA constant current)? is it enabled by default in the NI 9234? if yes how can I switch it off?

0 Kudos
Message 1 of 1