NI MAX - implementation of preassure device

[Adrian08]

Hey,

I'm trying to implement two preassure measurement devices (DMP331 - BD/Sensors) with a range of 4 - 20 mA (-0,5 to 0,5 bar rel.) into LabView. They are attached to a NI-USB6008 which is plugged right into the Comupters USB-port. The current is correctly delivered to the USB6008 when manually meassured, but do not get through to the NIMax-task. The Values shown there are oscillating throughout the entered range (connection in on differential, resistance: 502 Ohm, measuring continuous captureing every 1k Values with a rate of 1k Hz) and are doing the same in my LabView front panel.

Is there anyone who can give me a clue on what i can try to fix that ?

Many thanks for every help,

Adrian

[jSturm]

Hey Adrian,

So you have a differential voltage measurement with an extern resistance of 502 ohm, right? (Comply with a measuring range of 10V?)

What do you mean with 'oscillating throughout the entered range' exactly? Seems it like the measuring range is exceeded?

Are you sure to use the exactly channel-pairs (1/5, 2/6...) of USB 6008 for a differential measurement?

Otherwise the information you give about your measurement appear to be right in my eyes. Maybe you can add a screenshot of the signal in MAX?

Jeremy.