NI 9205 input range

[bkling]

I am going to be using the NI 9205 analog input module in a cDAQ-9172 chassis to read postion from a linear pot.  I want to get as much accuracy as I can out of this pot.  The pot has a 0-20mA output and I want to read this on a 0-5V scale.  My question is this: The 9205 has a range of +/-5V, does this mean that if i set the limits to 0-5V that i will only be using half of the possible resolution of the input?  If so is there a way that I can configure the card to use all 16 bits on the 0-5V input?

[Travis_W]

Hi,

The available input range settings on the NI 9205 are ±10V, ±5V, ±1, ±.2V according to the specifications on page 19 of the NI 9205 Operating Instructions.  These are the only available ranges over which the 16 bits of resolution can be spread.  To make use of all 16 bits of resolution, you would need to add some external circuitry to the potentiometer to where the ouptput varied through a bipolar range such as -5V to 5V. 

Also, for reference, on the ±5V range, the absolute accuracy will be 6.22mV according to page 24 of the NI 9205 Operating Instructions.  How accurately do you need to measure your potentiometer signal?

Have a great day!
Travis W