Multiple readers of an RT FIFO?

[sciu]

Hi everyone

I'm using rt fifo queues to transfer logging data (DAQmx) and setting data, start and stop boolean etc. from the host to my PXIe controller. In most cases it works fine. However, when I want to send a "stop" boolean to stop the data logging, the command never (or just occasionally) arrives at the target's side. When no logging data is transfered the boolean arrives. When I start the logging, the "start" boolean arrives as well - that works fine.

I guess that the logging consumes to much resources of the rt fifo queueing?!? I've also tried to enlarge the pre-allocated queue size...

Thanks for any helpful suggestion :-).

cheers

[crossrulz]

Next to impossible to help without seeing some code.  It sounds to me like you are overrunning your FIFO and therefore your "Stop" message is getting lost.

[niarena]

yes, please create a snippet, or attach the vi

[sciu]

Good morning

Thanks for replying. It is not just a simple VI but rather a bunch of VIs that interact together. I'm going to attach the VI where the DAQmx output and the "stop" command are packed into the rt fifo queue. If this is not helpful or more VIs needed I might have to enclose the project folder...

I guess that it really might be an overrun of the rt fifo since the logging freq. is 2kHz and I'm not sure what size of the queue I have to pre-allocate...

many thanks

[sciu]

Hi everyone

It's me again ;-).

I've tried several times in many ways to solve the problem mentioned earlier. For some unknown reason a single boolean is not transfered via RT-FIFO to a data logging VI. The "start logging" button transfers the boolean value to the RT-Target but is not visible when unbundled by Name from the RT-FIFO. For all other transfered data it works well.

I've detached the "start logging" value from the "data logging" vi. Instead I've tried to solve this issue on another way by using true/false-queries.

Another Problem is that the .tdms create function does not create a "tdms file out" reference when the "tdms create" function is called. It returns just a "0". Also the data from an AI-Task seem not to be read and properly prepared for logging.

Does anyone have a Suggestion or idea what is going wrong or what is not properly designed?

I've attached the program file and a Picture of the programming tree with the Data Logging vi.

Thanks a lot for any helpful suggestion :-).

Best

[sciu]

Hi again

I've just added a new Version of the "data logging" file. The remaining problem is still the "tdms file out" that is just "0".

Thanks a lot

[sciu]

Hi everyone

Maybe it's a stupid question but I'll ask it anyway ;-):

I've tried several times in many ways to solve the problem mentioned earlier. For some unknown reason a single boolean is not transfered via RT-FIFO to a data logging VI. The "start logging" button transfers the boolean value to the RT-Target but is not visible when unbundled by Name from the RT-FIFO. For all other transfered data it works well.

I've detached the "start logging" value from the "data logging" vi. Instead I've tried to solve this issue on another way by using true/false-queries.

Another Problem is that the .tdms create function does not create a "tdms file out" reference when the "tdms create" function is called. It returns just a "0". Also the data from an AI-Task seem not to be read and properly prepared for logging.

Does anyone have a Suggestion or idea what is going wrong or what is not properly designed?

I've attached the program file and a Picture of the programming tree with the Data Logging vi.

Thanks a lot for any helpful suggestion :-).

Best