Hi,
We have 2 similar measurement setups for pulsetrain measurement (measure duty cycle). We however see very different results in measurement resolutions :
Setup 1 : PCI-6602 (8x 32-bit counter)
We configure a counter to measure a pulsetrain with this code :
After this code, we just do a "DAQmx Start" and "DAQmx Read"
- With this code, we see that the measurement resolution is 0.25 µs
- If we change toe Digital Filter.MinPulseWidth from 5E-7 (=0.5µs) to 1.5µs, we see that the measurement resolution lowers to 0.7µs.
Then we have :
2nd setup : PCIe-6321 (4x 32bit counter)
that has the exact same SemiPeriod measurement. With the MinPulseWidth at 5E-7, we have a measurement resolution of at least 0.01µs.
(25x better than other setup).
Can anybody give any advise on :
- what (and why) is the influence from the digital filter on the SemiPeriod Measurement resolution?
- why does the PCIe-6321 give much better resolution that the PCI-6602?
Some more details :
- LabVIEW 2015
- DAQmx version 18
Kind regards,
Thomas.