About the MCC 172 DAQ HAT sensor selection

[ninamihalios]

Hello Technical Engineer, I am now facing a hardware problem about the MCC 172 DAQ HAT, because I am new to the hardware, this is a project task, I need to use it to measure the vibration signal when the bearing is rotated. Our laboratory used a good data logger, pressure sensor and accelerometer, which are all magnetic and adsorbed at the position that needs to be measured. But I never got to know the sensor in depth, and I didn't know which one to choose to connect with the MCC 172. I saw an article before, it uses 805-0500 TO5-3 accelerometer, I bought it back and found that it can't be measured, I have set up this aspect of the environment, and the web server can enter normally, but after clicking 'start', there is no map, and the signal cannot be collected. Later, I found out that the power supply voltage of this accelerometer is more than 18V, and the power supply of Raspberry Pi is 3.3V-5V. I would like to ask if you can help me solve this problem and provide me with a specific model of accelerometer, or a sensor with it, thank you very much!

[Fausto]

Hello @ninamihalios.

The MCC 172 supports two IEPE accelerometers, with an IEPE compliance voltage of 23 V max and an IEPE excitation current of 4.0 mA min.

https://files.digilent.com/datasheets/DS-MCC-172.pdf

https://mccdaq.github.io/daqhats/_static/esmcc172.pdf

The 805-0500 specifications appear to be inline with the MCC 172 specifications.

https://www.te.com/usa-en/product-805-0500.datasheet.pdf

Did you use the 10 mV/g sensitivity spec (or the actual spec provided on the manufacturer's certificate) in the MCC 172 web server example?

Verify the wiring connections to the leads on the accelerometer.

Regards,

Fausto

[ninamihalios]

17 hours ago, Fausto said:

@FaustoHello Mr. Fausto, thank you very much for replying to me, the sensor model I use is 805-0500-01, it comes with bolts, so I bought a magnetic device, it is the same as the 805-0500 in terms of parameters. My problem is that after clicking 'start', the code will also give an error, and I will show you the detailed picture.

 

[Fausto]

Hello @ninamihalios.

Which Raspberry Pi module and Raspbian OS are you using?  Run the command cat /etc/os-release.

Which daqhat library do you have installed?  Run the command daqhats_version.

Does the MCC 172 Python example, continuous_scan.py, work without prompting an error?

Be sure to close the MCC DAQ HAT Manager - MCC 172 Control Panel applet before launching the MCC 172 web server example.  Only one example should access the board at any given time.

Regards,

Fausto

[ninamihalios]

Hello@FaustoI now close the control panel applet,Only open the web server,The signal curve can be depicted,Then I pause the web server,Run continuous_scan.py this script file,There seems to be a problem with the operation,I don't understand what the reason is,Is the web server in the open state,And then to execute this script to succeed? I also have a question about how I can transfer the curves to my computer and analyze them in software.

[ninamihalios]

@FaustoHello engineer, the signal map I got after measuring the data in real time, the ordinate range is about -1.5-1.5. When I shut down the web server, executed the csv file after fft_scan the script file, and imported the first column of time data data into MATLAB, the graph obtained was very different from the real-time measurement, the amplitude was reduced by ten times, I changed the sampling frequency in the script file to the same as the sampling frequency monitored by the website, but the sample size was different, I wanted to ask why the difference between the waveform spectrum displayed after importing MATLAB and the website monitoring is so large.