AI acquisition with 2 NI cards

[Simon74]

Hi,

I have a question regarding a case of AI acquisition with 2 NI cards. (PCI-6025E)

My system is using 2 NI cards; dev1 is acquiring analog inputs and its conversion is done by dev2.

Some engineer in my company wired them previously. In this case, how can I make an AI acquisition code?

A:

DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev2/ai0:3","",DAQmx_Val_Diff,-10.0,10.0,DAQmx_Val_Volts,NULL)); 
DAQmxErrChk (DAQmxSetAIGain(taskHandle, "Dev2/ai0:3", gainValue)); 

B:

DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0:3","",DAQmx_Val_Diff,-10.0,10.0,DAQmx_Val_Volts,NULL)); 
DAQmxErrChk (DAQmxSetAIGain(taskHandle, "Dev1/ai0:3", gainValue)); 

When I test these A and B codes, only A is working. I wonder this is because AD conversion in the 2nd device is operational and the 1st device is not using AD converter.

I need your advice on this case.

Thanks,

[Dennis_Knutson]

That's confusing. Dev1 is set to acquire and convert it's ai0:3 inputs and Dev2 is set to acquire and convert it's own ai0:3 inputs. Don't know why you think Dev2 is doing the conversion of signals acquired by Dev1.

[Simon74]

Yeah, I'm confused, too. The engineer said he connected the wires like that way. There could be some mis-understanding if he really did it. I wonder this confusion is caused by interchanged device ID.

We have 2 radar and 4 radar system. The 2 radar system is using 1 PCI-6025E and the 4 radar system is employing 2 PCI-6025Es. When we made 4 radar system, someone interchanged connections, I guess.

BTW, AI acquisition on device 2 is fine...and I suspect AI inputs are all assigned in device 2.

[ie.aleja]

Hey Simon,

So is the dev1 outputing any signals that are being acquire by dev2 so it can do the conversion? It's not very clear the hardware set up, if you can provide more information we can come up with diagnostic and a solution for this issue.