how do you change the gain on a MIO-16E-4 DAQ

[milkb1]

Hi,

I am reading a voltage from a photodetector.  I would like to amplify the voltage by using the instrumentation amplifier on the DAQ(PCI-MIO-16E-4).

I would like to know if there is a way to change the amplification on the DAQ in LabWindows/CVI.

For example: photodetector picks up a light at 100watts I would want to decrease the amplification. Then the photodector

picks up a light at 20watts. I would want to increase the amplifaction. So is there a way to program this in CVI.

Thank You

[RobertoBozzolo]

Some of the DAQ routines accept gain as a parameter. For example, SCAN_Op and SCAN_setup accept an array of channels and the corresponding array of gain as an input.

Depending on your application you have different ways to do this: are you acquiring one measure or many? And a single point or one / many waveforms?

[milkb1]

I will be acquiring many samples or measurements at one waveform. Meaning the user will enter a power that they want to test at. The test machine will gradually work its way up to that max power. I will take measurements up to the max power. But because the a/d board is only 12 bits, I need to adjust the gain every "x" amount of power so that the a/d can convert it. Also I will be using the traditional NI-DAQ

Thank You

[josswern]

if you can afford a little time gap between consecutive measurments and your signal is not transient,
you can always take a short 'test-measurment' before, with max. gain, then calculate the optimal gain setting which will fit without overload and then use that value for the actual measurment.
simple way of 'autoranging' 🙂