usb-6212----can't read simple voltage AI.

[carideom`]

I just don't get it! I've got Labview 8.5, NI-DAQmx 8.6. I just purchased the NI USB-6212 portable daq board and I'm new with SignalExpress LE. I cannot get the USB device to read the voltages that are pressent on its terminals. My system is a simple strain gauge pressure transducer (full bridge),  a signal conditioner (Newport iDRN) and a 12 volt power supply. I measured my low pressure voltage at -0.155v and my high pressure at 11.69 v. I have scaled this voltage range to be 0 - 200 psig in SignalExpress; however, I either get '0' psig, or, '21' psig! I have tried five (5) transducers. All other equipment, including the USB-6212 is brand new!

I'm using

[PBear]

Hi Carideom,

Have you been able to read the voltages properly prior to the scaling? For example, does your task run properly in SignalExpress without the custom scaling applied? A good way to test is to open Measurement and Automation Explorer and run a Test Panel on the USB-6212 and see what values the Newport device is outputting. Also, you may want to double check this with a scope. Double check your range that you are using for the acquire voltage task because you seem to be railing on scale values below the maximum scale that you have setup.

Make sure you are setting up your connections properly as well. You may want to look at the Field Wiring and Noise Consideration Developer's Zone article. If you could shed some more light on your connections and also try testing your USB device by supplying a known voltage source via a signal generator or wiring your Ao to your Ai and producing a signal in the test panels. Look at the following KnowledgeBase (KB 35TGB1VM) about how to do this internally.