NI USB 6211 - Why does the setting "input terminal configuration" always returns into "default"(=differtial mode)?

[sam B]

I'am using the analog inputs from the USB 6211 device to measure analog voltages from batteries. All inputs are single ended (RSE) connected. In the VI, I select "RSE" in the "input terminal configuration", but when I run the VI, this setting always returns into "default" (which is the differential mode), resulting in a saturated voltage (+10.8V).

I've read the document "Field Wiring and Noise Considerations for Analog Signals" and I understand why the voltage saturates to 10.8V.

My problem is that I can't select permanently the RSE-option.

Can anyone help me?

[Dennis_Knutson]

Where are you setting the input configuration? I hope it's in the top level VI where you call DAQmx Create Channel and that you are not opening the subVI and changing it there. That, of course, does not work. If you are setting it in the top level, you should post your code.

[sam B]

I'm setting it in "DAQmx Create Channel (AI-Voltage-Basic).vi"

What do you mean by "top level VI" and "subVI"?

Which code do you mean?

(I started with the example "Cont Acq&Graph Voltage-Int Clk.vi" )

Message Edited by sam B on 02-02-2009 09:22 AM

[Dennis_Knutson]

If you don't know what a subVI or top level VI is, then you need to go straight to here and spend some time with a tutorial or two before you start writing any code.

The example called Cont Acq&Graph Voltage-Int Clk is the top level VI and DAQMX Create Channel is the subVI. As I already said, if all that you are doing is opening the subVI and changing the setting there, that will not work at all. You have to set the parameter in the calling VI (the top level). Once you have made the change, DO NOT save the shipping example. Do a save as and place the modified VI in a different location.

Message Edited by Dennis Knutson on 02-02-2009 08:38 AM

[sam B]

That's all I needed to kwow, thanks!