BNC 2090A

[fishbulb2]

Hello,

I have a BNC 2090A board that for some reason will no longer put out more than a few tenths of a volt out of the AO0 slot. If I try to run the same signal out of the AO1 port, it does it just fine. Is this a problem that I can fix myself or would I need to send the unit in for repairs.

Thanks guys.

FB2 

[Dennis_Knutson]

The BNC 2090A is just a dumb terminal block and is not supposed to output any voltage at all.

On the other hand, you would typically connect the 2090A to an actual DAQ device and some of these are capable of outputing a voltage. If you have an actual DAQ board connected, then you would first determine whether AO0 of that is outputting anything. That would be done by disconnecting the cable from the 2090A and probing the DAQ device connector pin. You can also run the self-test of the board in MAX with all cables disconnected. If you determine that the DAQ board is not outputting anything, post back. You'll probably need to send it back for repair.

[fishbulb2]

Thanks Dennis,

Seems like I may have gotten some of my terminology wrong. It's a NI DAQ board. (Has 8 BNC inputs and 2 BNC outputs labeled AO0 and AO1). It's the AO0 port that I can't get to change voltage beyond a couple tenths of a volt. If I run the same protocol on the AO1 port, I see a nice 5V change. I'm testing the voltage out of these channels both with a volt meter and an oscilloscope and getting the same result either way.

FB2 

[Dennis_Knutson]

Well, you have not provided the model of the DAQ board, but if in MAX you see the problem with the test panel, then it could be damaged. Did you run the self-test? Before you contact NI about an RMA, you'll need to do this.

[fishbulb2]

Hey Dennis,

The software reported the self test as passing but when we recorded the voltage off of the cable pins out of the board, we are still getting a -.42V change  when we ask for 5V. We tried to do a self calibration after disconnecting from everything, but the software said the calibration failed. The board is a PCIe-6251. We alsotried simply reseating the card inside the CPU but that did not fix the problem. AO1 still seems to work fine.

FB2 

[Dennis_Knutson]

I'm confused. The PCIe-6251 does not have any coax connections. Assuming that you may have gotten your terminology wrong again, you should probably contact NI directly. They will have warranty status, etc.

[fishbulb2]

Hmmm, that's odd. The card inside the computer is a PCIe-6251 then runs via a cable to the BNC board. We measured the voltage at the pins in the cable between the card and the BNC box. Do you think I have the card name wrong?

[Dennis_Knutson]

No, you don't have card name wrong. You just need to forget about the cable and bnc board fro a minute. It's confusing to say that the DAQ board has the coax connectors. To at least isolate the problem, measure the voltage directly on the connector of the PCIe board. I can't really tell from your desctiption whether you have done this. If you have done this, then never mind. The cable from the PCIe board is pretty robust but they can become damaged (i.e. by repeated bending) and you want to make sure the fault is in the DAQ card and not the cable or the box with the BNC's.

[fishbulb2]

Thanks for all the help Dennis. I called NI and they had me download some additional diagnostic software off of their website. When we ran it, the card failed at AO0 and showed exactly the error I was seeing. They were very helpful. The card was still under warranty and their customer service was pretty great. 

FB2 

[Ipshita_C]

Hi fishbulb2,

Please post your DAQ-related questions to the DAQ forum. It not only enables the right group to get to the solution quickly but also enhances your support experience. Thanks!

Ipshita C.