I can't connect the USRP2 with my computer.

[help_me_yann]

The IP address of PC is it set to the same network used by USRP??

Yann.G

[help_me_yann]

Hi,

Finally, I can run my system at 20MS/s. But the error message "Overflow" still appears after a certain time. (5 min, 10 min, 20min). 

Yet, my memory and my network aren't satured. (such as attachement)

Have you encountered this problem?

Thanks

Yann.G

[help_me_yann]

PS: I want my system to run for 20h

[Sarah_Y]

Hey Prabhat,

Just to make sure I understand your setup, you have an Ettus N210 and you want to use the NI-USRP driver.  The 1.0 driver only works with a few daughterboards.  I'm not sure which one you are using, but this could be part of the problem.  Based on the error code that you got, it sounds like you are getting an error for UHD or one of the Ettus tools.  Are you trying to use the NI-USRP Configuration Utility, or the UHD version?  Once you have the NI-USRP firmware and FPGA image loaded onto the device, you should only use the NI tools.  Here's a knowledge base about how to use the NI tool to change the firmware and FPGA:

http://digital.ni.com/public.nsf/allkb/F622E3B3B9CC34B6862579D500705272?OpenDocument

Also, you need to make sure that you have your static IP address set correctly.  The default IP address for the USRP is 192.168.10.2.  You should set your computer's IP address to 192.168.10.1.  If you are unsure of the IP address, you can change the subnet to 255.255.0.0, which will allow you to see more subnets.  Let me know which tools you are using and if you are still unable to talk to your USRP.

[Sarah_Y]

Hi Yann,

The buffer overflow indicates that the data is being written faster than it is being pulled off the buffer.  This may be a limit of how fast the computer is able to pull the data from the Ethernet and write it to disk.  The network may not besaturated, but 20 MS/s is the upper limit of what is possible to transmit over a gigabit Ethernet bus.  One thing that you could consider would be changing from acquiring a 16 bit sample to an 8 bit sample.  That will increase the amountof data that you are able to transfer.  Getting a system to be able to sustain this high throughput requires some trial in error to get the number of samples per read at the right rate that the computer can handle.  Another thing you can tryis to increase the maximum number of elements that you will allow in your queue.  Also the more indicators that you have, such as the append array, on your front panel can potentially slow down your acquisition.  A final suggestionwould be to make sure that you are using the Ethernet card vendor's driver, not the default Windows driver.  This has provided slight speed increases on some computers.

The IP address of the computer needs to be on the same subnet as your USRP.  For example, if your USRP is 192.168.10.2 (default), you should set your computer to have IP address 192.168.10.1.

[help_me_yann]

Hi,

I can not understand my problem: why th USRP-2920 put on overflow whereas buffers are not filled at all, tat my I/0 to disk isn't full? Moreover, why this system runs with a computer less efficient. Nobody has encountered this problem?

Would it be possible to have the DLL code of module "niUSRP Fetch Rx Data (CDB)?

Thanks

Yann.G

[Sarah_Y]

Hi Yann,

The .dll code is proprietary and not something that can be released.

Let's consider the amount of data being sent over the gigabit Ethernet:

You set your sample rate to 20 MS/s.  This means you are taking 20 MS/s of I data, and 20 MS/s of Q data.  Each I sample and each Q sample is 16 bits.  So you are taking 16 bits * (20 * 10e6) * 2 = 640 Mbits/s of data.  Although it is called "gigabit" Ethernet, the practical limit is closer to 800 Mbits/s.  Your data rate is very fast and close to the limit of what gigabit Ethernet can do.  If the Windows OS tries to access the port for any reason, or if the port is not fully powered (which Erik L mentioned back on the first page of this thread) the streaming performance can be greatly effected.  Another issue can be the write speed of your hard drive itself and where on the hard drive the data is being written.  A hard drive can only spin and write data so fast.  If the data is being written on the outer portion of the hard disk, it can be written faster, but as the data is written on the inner portion of the disk, it is not possible to maintain as high of a write speed.

This is a problem that I have encountered, and it is difficult to get the streaming rate to be 20 MS/s consistently for long periods of time because of things such as Windows firewall, virus scans, chip set of the computer, Ethernet card, and other instabilities on Windows.  If you do not need all 16 bits of I and Q data, setting the data width to 8 bits will allow you to maintain 20 MS/s easily.

[help_me_yann]

Hi Sarah,

I agree with you, but the data rate max is 25MS/s (according to the document), and this documents doesn't specify a run time max. Durthermore, regarding to the write speed of the hard disk, I oscillate between 0% and 30% uptime on the disk. Sor for me, the problem is not here. My Windows firewall is disabled, I have not virus scans, and the green ethernet is disabled.

My contraints: data rate->20MS/s, Recording time->20h, Sample-> 16bits

Thanks

Yann.G

[help_me_yann]

In attachments, statement of task manager whan the system crashes

[help_me_yann]

Hello,

After several tests, the system will also overflow to 10MS/s and 5MS/s. I get the same error message "overflow" to the output of niUSRP Fetch Rx Data.vi

Would you have any others solutions?

Thanks