Hi All, I want to record data triggered by certain events by FPGA memory method node to Block Memory. I did that. But I want download this data at a later time. The loop rate at which the code in the FPGA runs is much faster than the rate of the events. I know how to send data from FPGA to RT side through FIFO's and write the data in RT and download it later. But in this method there is an issue of elements remaining. Is there any way I can save/record the data from the FPGA directly to memory? Given the fact that I don't need it in RT, only need to download it later.

LabVIEW

Recording data at desired instants in FPGA using Memory Method

You are wanting to stream data from your FGPA to your RT. The data comes in bursts, and you don't want to lose anything.

As deceased said, you should use DMA.FIFOs to achieve this. Deceased's method of two sequential FIFO reads on the RT side is correct; the first reads 0 elements and the second reads the number of elements found to be remaining by the first 'read'. You have remaining elements because you are writing elements between the two reads (plausible).

I do not understand the problem; you should be reading in a loop, reading values from the FIFO on the RT side continuously and logging them to a TDMS file (for example). So you should eventually run the buffer down when you turn off acquisition on the FGPA. Your problem might be solved by something simple like sending a stop command to the FPGA to stop writing to the FIFO.

Another tip; your DMA.FIFO can have different buffer sizes on the FPGA and the RT. You could use this to store a large number of elements (10's to 100's of ksamples) on the RT and then read them out all at once. I would recommend to read a smaller number more regularly though if the RT would just be sitting around not doing anything between the big reads though.

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