Phidgets Forums

I am using a 500Kg load cell (3140_0) and a DAQ1500 bridge to measure a reciprocating bending load on a beam. I capture my data samples at 33Hz and accumulate a large number of these samples and then display and save the peak value from the large sample size. By sampling across a large number of cycles that are not harmonically related to my sample rate I can get very close to catching the peak moment that is applied to the beam. When I run the test at a low bending frequency, like less than 1Hz, I get a bending moment of 200Nm, when I increase the bending load frequency to 5Hz my measured bending moment drops to about 100Nm. I am as sure as I can be that I am still catching the peak and that my applied load has not changed. What it looks like is that the DAQ1500 has some heavy signal (noise) filtering that is limiting the bandwidth of amplifier and my measurements. Is there a way to increase the measurement bandwidth of the DAQ1500? Can I remove some filter caps to increase the signal bandwidth? Do you have a bridge with higher amplifier/measurement bandwidth?

I had an old 1046_0 4 input bridge lying around so I hooked that up in place of the DAQ1500. While it does roll off at the "higher" frequencies, it was significantly less than the DAQ1500.

Load Freq_________~1Hz______________5.3Hz
DAQ1500___________240Nm_____________90Nm
1046______________240Nm_____________220Nm

This is probably OK for my purposes - I can compensate for the rolloff in software. However, I did not expect the signal bandwidth to be so low on the DAQ1500 (unless I am missing something)