about sampling rate

[Dost]

I have some question and iwant to clear it.

i am acquirig data from a flow meter it is giving current that i changed to volt by inserting resistor that ranges from 0 to 5 volts. it  should be DC voltage i want to know how should i set the sapmling rate of this signal becaz according to theorm it should be twice the maximum frequecy but in this case it is DC voltage.my programming is doing fine it gives me the correct reading that i can check with tthe reading on flow meter.

my second question is where is sampling rate given i am using config.vi,AI.vi and Read.vi i am usingdefat values and in AI start .vi .further mmy data acquistion loop is executing at 1 sec should it bother to acquire data if yes what should i do.

my third question i read article about data sampling it says if sampling frequency is not correct than there could be data clipping how can i know my data is clipped becaz to myunderstanding this should be done by DAQ card,Iam usin g NI card E series.

[Buechsenschuetz]

Of course the Nyquist theorem rather applies to AC voltages with given frequencies. On the other hand, what you want to measure probably is NOT pure DC current. If there were no changes in current there would be no need to measure them, right?

So there probably will be changes in DC current output of your flowmeter. You should check the manufacturer's data sheet for max frequency response or rise time of output signal, and set your sampling rate accordingly. However, you should do some oversampling to reduce the influence of noise and erratic readings.