Developing a SIMO modal test VI

[pwb]

Requesting input on the following objective:

-16 response channels, SIMO testing.

-allowing for choice of receptance, mobility or accelerance; turning off/on all 16 channels, and only output data and other functions active for the "on" channels.

-full labelling and identification, such as location DOFs axes and numbers for sensors and the FRF matrix (Hj,k ) that can be mapped to FE node numbers, date/time etc, option of also labelling each response channel or hammer as a "reference DOF".

-all standard settings such as sampling rates, windows, triggering, etc.

-output time domain data to one Excel file, with column headings.

-output frequency domain data to one Excel file, with column headings; with real and imaginary components.

-output FRFs in UFF format (using the UFF binary to ASCII UFF format converison VI).

-hit acceptance criteria to be set using an amplitude-time envelope for the hammer, double hit for the hammer, decay enveolpe for the response sensors, (to be user defined as in the exisiting seproj file availble in "examples").

-coherence, also as part of the hit acceptance, and as output data in a seperate excel, possibly to be available for all input-response pairs, but as a minimum for a chosen pair.

[Jim_S]

Hello Pwb,

After looking over your post, I think we need to break this down into smaller pieces. I think the best first step would be to look at the DAQ portion of this and I will part in this forum. As for the other questions about saving to a file, displaying the data, etc, I would create a different forum post to attack those issues.

First couple of questions are the following:

1.) What device are you using?

2.) What programming language are you using?

3.) Could you provide the input and the outputs of the system are?

4.) Are these outputs all analog signals? What types of analog signals, accleration, strain, etc?

Knowing this, I can guide you to the best examples and documentation to assist you with this issue.

[pwb]

Hardware:

PXI 1042Q chassis.

PXI 4498

PXI 6143

BNC-2110

SCB-68

BNC-2144

USB 4432, also for accelerometers and hammer.

Kistler Impulse force hammers, 9722A500 & 9722A5000.

Software:

-NI academic site license Fall 2009 (1 upgrade to Spring 2010), including Labview core Professional development System, Sound & Vibration, and lots of other kits and modules.

-Already using a VI for SISO: "Impact Test with SW Trigger UPDATE 30_04_2010 (DAQmx)(2)"; attached here

-Needing two sub VIs: "Find Threshhold Crossing" & "SW Analog Triggering_DAQmx"; attached here

-Also needing another VI, to convert the output UFF 58 binary file into ASCII UFF 58; I will add to the next post.

Signals: all analogue

Inputs:

-1 force input channel, currently the hammer, but later, this might be a shaker system.

-15 response channels, priority is for acceleration. A capacity to select between displacement, velocity and acceleration would be useful.

Outputs:

-All raw time-domain sensor data.

-All frequency-domain sensor data.

-A record of the settings chosen by the user might also be useful (eg window choice, sampling rates, sensitivities, etc), as part of the documentation of the test conditions, as well as all the information such as sensor node location number, direction (x,y,z in translation and rotation, + or -).

-FRFs, full data, including the current format as in the attached VI (which is then converted to ASCII UFF58 format).

-Coherance.

Other output data will be inlcuded, but I need some time to plan this. I was thinking, the first step is to add more response channels?

[pwb]

UFF convertion file attached

Thanks to Doug Bendele for originally providing these VI files last year.