Search the Community
Showing results for tags '6723'.
This is a post as a reference to others on how I resolved my ghosting issues. Well mostly resolved, I still have a 1mV per 1V adjustment. Works fine with my hardware in between. You may want to tweak the values around to get none at all. Feel free to post your values and how you fixed ghosting issues. I only added Crosstalk as a reference in subject for those that are unaware of ghosting. Same Topic on NI Forums: http://forums.ni.com/t5/Multifunction-DAQ/Ghosting-Resolved-Crosstalk/td-p/3196396 My Offline Setup: Direct connection of a NI PXI-6723 to a NI PXI-6255. I tweaked around with the capacitors, but not so much with the resistors. Ghosting was resolved having a 100K resistor and 25nF capacitor on each Analog Input Signal to GND. A dummy channel (in my case I just added an extra AI reads to DAQmx AI) between each Analog Input Signal. These dummy channels were connected to GND using a 100K resistor and 47nF capacitor. I had to reduce either my rate or the AIConv.Rate proprety node. My Live setup with the minor hardware in between: I had to remove the 100K resistor and 25nF capacitor on the Analog Input Signals (This caused too much voltage drop on the system). Everything else remained. No ghosting at all. Other References: How Do I Eliminate Ghosting from My Measurements? M Series User Manual (Chapter 4)
I'm reading a sine wave generated by a AO DAQ and reading this same signal with another AI DAQ and a DMM at the same time. AO is set at 0.65V AI RMS reads 0.5VÂ±0.0056 DMM reads 0.46053V Â± 0.00001 0.65/1.414=0.46 so the DMM read is accurate. What makes the RMS LabVIEW function not reporting the accurate information? Could it be the Glitch Energy affecting the read? On a side note, I also need an accuracy of 0.2%. AO generates a 3KHz signal at 0.65V (450KS/s @ 150S/Buffer). AI reads at 90KS/s at 15KS/channel. DMM a 34401A is set VAC. Thanks