Data Acquisition Idea Exchange
I have an application in which I have to digitize a pulse across a shunt resistor. The common mode voltage can be up around 60VDC. The digitizing cards I was able to find cannot perform a differential measurement without digitizing both sides of the resistor and then subtracting. This method causes a lot of error due to the needed voltage ranges. I have been able to digitize some of these pulses with the PXI-4072 DMM with great success. However, I can control when those pulses occur and setup trigger lines as needed. Other pulses I need to digitize will occur whenever the UUT decides to put it out. What is really needed is a way to trigger the DMM on a measured voltage level. Just for reference, Agilent's PXI DMMs can do this. It seems such a shame I haven't found a way to do this with NI's DMM. As a final thought, some pretrigger data would be needed to properly capture the pulse. Though, pretrigger data would be nice in any hardware triggered acquisition.
