PXI-5112 differential acquisition

[RPBCN]

Hello,

I have installed a PXI-5112 in a PXI-1000B chassis. I have to use it to take differential measurements between the two channels, like explained in the following article:

http://zone.ni.com/devzone/cda/epd/p/id/5682 

So far it is not working, it is getting only half of the sinusoidal.

In a different system I have a PXI-5114 installed in a PXI-1042 chassis. Over there the differential measurement is working well. The differential measurement VIs are exactly the same in both cases, and they should measure exactly the same. Basically, one system is a duplicate of the other, except that the PXI chassis and the Scope card are different.

I am using Scope 3.6 in on system (with the problem) and Scope 3.5 in the other system (working fine).

I noticed one difference in the way the Scope cards are recognized in MAX. In the system that is working (see picture PXI5114_PXI1042.JPG) I have the Attributes and VISA properties, and I can do Self-Test and Open Test Panels. All of this I cannot do with the other system (see picture PXI5112_PXI1000B.JPG). Is this bad configuration in MAX the problem? Or maybe I have 2 problems?

Thank you,

Raimon Pousa

[DFGray]

The 5112 is a relatively old product (~12yrs).  As such, it uses the old DAQ driver as a basis for its driver.  The 5114 is much newer and uses the newer DAQmx driver as its base.  This should account for the differences in how the product shows up under MAX, although you should be able to get some sort of test panel for both.

You may have a hardware issue.  Look at the raw output coming from both channels of the 5112 to make sure it is reasonable (use the same VI, but don't subtract one channel from another - double check using NI-SCOPE Soft Front Panel).  I suspect you will find your problem there.  If that does not help, please post your code and what you found and we can keep looking.

Good luck.

[RPBCN]

Hello,

Thank you for your reply. In fact I had a wiring problem. It was misleading, because it affected only one of the 2 channels so I thought the signal substraction was not working.

So problem solved.

Thank you.