Connection of Voltage Signal to PCI 6259 in Differential Mode and using it in MATLAB / Enabling LowPass Filters in MATLAB

[Control_Eng]

Hi,

I'm working on a project in which I want to integrate a PCI 6259 to meassure the step response of a physical system. The Data will be handled with MATLAB rather than LABVIEW.

Right now, I have some problems regarding the connection of the Voltage signal and the configuration of the channels in MATLAB.

As shown in the manual, two channels are used when working in differential mode.

In the Manual, the corresponding Inputs are marked with a + and - sign.

Thats just not the case when I look at my PCI 6259 Datasheet. There I see Analog Inputs AI0 to AI31...Which pairs of this analog inputs form a differential input together?

In the documentation of the BNC-2110 it seems to me that AI0 and AI8 for example form such a pair. Is that true?

Next thing is:

How do I configure MATLAB so that MATLAB know that TWO channels together form an Input? I see only the option/command to add one channel. How can I "link" two channels together in MATLAB?  Or is this done somehow automatically?

Last but not least:

How can I enable the LowPass filters so that they keep some noise out of my measurement?

Somebody that works in my company told me, that I have to do all configurations in MX?!

Right now I'm quite idealess of how to proceed further 😞

That's why I depend on your help 😉

Thanks for reading my question and feel free to respond to it 🙂

Thanks in advance and best regards,

Manuel

[Control_Eng]

UPDATE:

I figured out how to connect the signal correctly to the NI PCI 6259.

Meassurements are quite good.

Only problem: There is a 30mVpp White Gausian Noise in the measured signal. Since I want to meassure also very small signals (around 100mV for example), I need the hardware lowpass filters.

I also tried a running mean filter but that "damages" my step response.

So only remaining question:

Is there any possibility that I can enable the Hardware Lowpass Filters within MATLAB?

[Elisa_D.]

Maybe this will help you:

http://forums.ni.com/t5/Multifunction-DAQ/DAQ-matlab-lowpass-filter-enabling/td-p/768667

[Bobity1]

Manuel,

I'd be interested to hear how you did :  "How do I configure MATLAB so that MATLAB know that TWO channels together form an Input? I see only the option/command to add one channel. How can I "link" two channels together in MATLAB?  Or is this done somehow automatically?".

I'd like to do this as well.

The header shows for AI 0 for instance :

Pin 68 AI 0 (AI 0+)

Pin 34 AI 8 (AI 0-)

Do I just connect an additional input wire from my source to Pin 68 & Pin 34 or do I need to do anything else in addition in Matlab so that it "knows" I'm doing differential input or is that handled by the NI-6259 card ?

Thanks

Bobity1