Using PCB instrumented hammer model 086D50 with module NI9234 and chassis NI cDAQ 9188

[Ema16]

Hi all,

I need to do an impact hammer test with a PCB 086D50 intrumented hammer. I am using chassis NI cDAQ 9188 with modules NI9205 and NI9234. The hammer is plugged into NI9234 and the accelerometers are connected to NI9205.

When I test the modules in SignalExpress I get not so good results for the hammer, but the accelerometers are ok. Also, if I test the hammer in NI MAX where I have the option to enable the IEPE the result is ok. In SignalExpress I couldn't find the option to enable IEPE.

I have no experience in using the softwares, but  I started learning. Does this mean that I need to program the acquisition system for my setup in LabVIEW? Also, does the equipment setup make sense, can the modules I plugged into cDAQ be used simultaneously? Do I need additional device for using the hammer with cDAQ 9188?

Many thanks

Emina

[dsb@NI · Accepted solution]

You can enable IEPE in SignalExpress. Here is a configuration for one force hammer and three accelerometers connected to a 9234.

You didn't mention the model for the accelerometers. Are they also IEPE sensors? If so, what signal conditioning did you add in front of the 9205?

The Sound and Vibration Assistant (built on top of SignalExpress) has an example for Impact Test. The Sound and Vibration Toolkit ships with a sample project for impact test. With free evaluation period, go ahead and take a look at how either of these examples implements the configuration and triggered acquisition.

[Ema16]

Thank you for your answer.

 I have solved the problem I had. I've done the some thing you suggested, but after running the SignalExpress in compatibility mode for XP operating system and as administrator.

Emina

[411051]

Hello ,

I am using the same impact hammer with same module , I am getting signals but finding difficulty in prdicting natural frequencies after observing Frequency Response Function Graphs( Magnitude , Phase and Coherence). Please  guide.

I 

[dsb@NI]

Please include some data and screenshots so that we may be able to provide specific help. 

Very general guidance for impact test:

1. Make sure you are not overloading any channels on impact.
2. Sample fast enough to capture the trigger and peak.
3. Use an analog reference trigger with pretrigger set large enough to capture the impact. Acquire long enough so that responses have decayed sufficiently.
4. Use either a force-exponential window or no windowing when calculating FRFs.
5. Reject any impacts that show multiple hits.

[411051]

Hello Doug,

Thank You .

Here i am attaching a vi front panel . Please guide to select weighing mode in averaging parameters as I want to measure natural frequency of pumps by using this vi. And i have selected window - force-exponential whether it is correct?

[411051]

Hello Doug,

I also want to know necessity of analog trigger..

Regards,

Samruddhi