Can I get 4-20mA into a USB-9211

[Stephen@Pilkington]

I want to set up a USB connected interface to three thermocouples and a pressure sensor.

The pressure sensor could be a 'strain bridge type' with an output accross its differential bridge outputs of 0-30mV (with a common mode votage <5V) or a 4-20mA type of sensor which I suspect with a 3 Ohm resistor could also make a differential voltage that this product could measure.

Critical to this adaption;
a) Is the on-board bias current to the input terminals mentioned in the manual small or stable and predictable?
b) Is there a software mode that reports mV rather than a thermocuple and cold junction computed temperature?


Thanks.

[George M.]

Hi,

The 9211 will only support differential AI from 0-80mV. It will not be able to measure current. To measure an AI voltage you can use the example found under:

Start>>Programs>>National Instruments>>NI-DAQmx Base>>Examples.

In this folder there are examples for the type of API you are using. I used the AI one point.vi for LV 7.1, and measured a voltage from 0-80mV. I hope this helps!

George