03-08-2011 11:11 PM
I am using LabView 2010, NI USB-9219, NI cDAQ-9172 and in addition to linear strain gages (5), I now also need to add one rectangular, planar rosette. Since there are 3 strain grids for this gage - I am assuming I would have 3 lead wires off the gage, therefore 3 channels, and would consider each grid as needing a quarter bridge-bridge completion. Just need that verified. Also, the axial testing machine is collecting data 1 every 100ms, so in the DAQ Assistant, a rate of 10 hz would match that, correct?
03-08-2011 11:16 PM
You'd have 3 lead wires off of each of the 3 grids on the gage, so a total of 9 wires. Yes. You'd want to measure it with 3 different channels all set up for a quarter bridge configuration. 10 Hz would be one reading every 100 msec. But you might want to consider a higher rate of acquisition and average multiple samples together. For example, 100 Hz and averaging the samples in groups of 10 to help reduce noise in the data.
03-08-2011 11:27 PM
Thanks for the verification. Because I cannot sync the LabView to the axial testing machine directly (too expensive to buy the components) it was suggested that I collect data from both at the same rate in order to be able to more easily compare the data - strain/time from LabView and load/time from axial tester.