Recently do a project about acquizeing voltage and current synchronouly ,then display. the design is welding a 0.5 ohm resistor(1%) in NI 6251 analog differential AI inputs, Then acquise the differential voltage at the AI input to convert to current. At the same time, I hope to grab the voltage of the analog input port. my issue is the current profile is no data. please help me .the program screenshot is show below. -------------------------------------------------------------------------------------------------- 1.may be you ask me why don't use no-dierential way to get voltage at all AI port, Then in software use minus to get the voltage at dierential AI inputs. this way will resolve my issue . i have a try ,but Current accuracy is fail. because my current expect range is 1uA~100mA. the samll current accuracy will not be promised if using single-way to acquise the voltage in NI 6251. NI 6251 Device spec(AI Absolute Accuracy) Nominal range(V) Absolute Accuracy(uV) Sensitivity 10 1920 112 5 1010 56 2 410 22.8 0.2 74 6.4 0.1 52 6.0 (i wanna use this range to measure samll current) ------------------------------------------------- Best regards Shawnh.Chen
↧