Re: First impressions

   As I mentioned before, I get crashes with the RT system when I try to pump too much data from the RT to the Desktop using my audio program or the Voice Recorder example program.  I suspect that NI set the audio sample rate at 8K in the Voice Recorder because of this issue.  If you go much higher, you risk crashes.  Obviously, though, 8K isn't ideal for full audio.  I'm thinking of dropping to a mono program just to get higher sampling rates.

   I was just wondering if anyone could verify that these limits make sense.  Here are the numbers:

   On MyRIO, which says it has a Xilinx Z-7010 FPGA with a dual core 667MHz processor, you can easily push 2 channels of 8KS/s data.  Each data point is 2 bytes, so that's a throughput of 32,0000 bytes/second through the Network Stream.

   I have another project that uses a cRIO-9068 chassis.  It has an Artix-7 FPGA with a dual core 667MHz processor.  On that, I've got a similar architecture that can push 32 channels of doubles from RT to host, at 15.625 KS/s.  That's a throughput of 4,000,000 bytes/second.

   Obviously, the fact that both processors both run at 667 MHz doesn't mean that they are equally as powerful, but the difference in throughput is a factor of 125!

   Oh, another difference is Wifi on the MyRIO vs wired 100Mbit ethernet on the cRIO.

   Can anyone (an NI, probably) verify that the MyRIO Network Streams really are topping out at around 32,000 bytes/sec?

Thanks,

   DaveT

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David Thomson Original Code Consulting
www.originalcode.com
National Instruments Alliance Program Member
Certified LabVIEW Architect
Certified Embedded Systems Developer
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