NI 9215 Input Range

[kyle.hall]

Quick question.  When I select the 0 to 10 VDC input range on the 'Create Virtual Channel' Daqmx vi while using a NI 9215 have I effectively made my 16 bit voltage input into an 8 bit voltage input or does the NI 9215 front end adjust itself to take advantage of the entire range of the ADC?  Thanks.

Kyle

[Seth_B. · Accepted solution]

The NI 9215 only has one possible range in hardware, ±10V nominal (it's acutally typically about ±10.4V, minimum of ±10.2V, max of ±10.6V).  If you define a smaller range, as in your example of 0V-10V, the NI-DAQmx driver will choose the smallest range that the device is capable of and uses that range in hardware.  Since there is only one range (±10V) that is the range that the hardware will use.

For devices capable of multiple ranges, such as X Series or the NI 9205, if you were to define a range of 0V-4V, the driver would determine that the smallest range that contains the user specified range is ±5V and set the ADC range accordingly.  If you were to choose 0-6V or ±6V etc, the driver would find that the smallest range possible is ±10V and use that range instead.