Synchronous pulse generation and data acquisition

[Virginia_Solomon]

I have my application where I must generate two pulses from two analog lines and synchronous my application must acquire data of these pulses when I have different loads for these pulses. Because the requirements are to have high sampling rate I am using two NI DAQ 6115 connected with RTSI.

I have in total 8 channels for acquisition on the two cards and two AO also spread, each card having one AO channel. Basic configuration is: two channels measurements for each pulse line in each board (one channel is current and the other voltage).

The pulse provision and acquisition must be synchronized. The basic analog part looks like in the attached image which was inspired from one of the DAQmx example “Multi-Device Synch-Analog Input-Finite Acq-Analog Start.vi”

For synchronization I setup AI as well as AO to receive on both cards on PFI0 a unique trigger signal provided by digital Port0\d0. For the analog out I did not find a good example and I setup channels as in the attached image.

My application has many variation of configurations: I could have active one channel AO in second board and different channels active in first board, so I can have any combination AI and AO of channels configuration from both boards, also pulses can have different duration or delays between them (you have attached one example of pulse). I think the analog part is good but I am not 100% but the problem might be in AO part.

Here are few instances of my test:

-Pulse generated in first board are correct acquired by channels from board one

-I set pulse in second board and I measure pulse with channels from second card. AI is triggered in this case but I got dead 0 acquisition while pulse is correct generated most of the time, very rarely I got the pulse. If I set 1ms pre trigger frames then the pulse is correct measured.

-I set and trigger both pulses and they are not generated but the AI measure noise.

 I need help as soon as possible, some examples with analog out from two boards synchronous connected.

Thank you,

Virginia

[MatthewL.]

Virginia,

Thanks for the overall scope of you system of the end goal and the set up. Could you expand upon the behavior you are seeing?

Is it throwing an error?

Are they appearing that they are synced?

Is it “passing/failing” the known instances of your test?

Thanks

[Virginia_Solomon]

Hi Matthew,

I figured out the problem simplifying the code and looking to each error code trying to follow the drivers recommendation and of course spending my weekend.

One thing is bad for sure: when I used the DAQ help assistant building a task from the two AO channels from the two cards joined with RTSI I found that an error is encountered as in the attachment, telling that the boards cannot support this. In the attached picture I used simulated boards but I used even real two 6115 boards and got the same error. I found in one article from your site that NI 6351 are allowed to synchronize AO channels as well as from 6115 daq cards. I even used more recent NI MAX DAQ drivers and for a case I explained with task built from AO from two cards the error is there.

Best regards,
Virginia