[Discuss-gnuradio] GRC with two URSP2+DBSRX and UHD

[Thomas Hobiger]

Hi everybody,

I am trying to get two USRP2 (each equipped with one DBSRX) to work together under GRC with the "Multi USRP Source" block. I have updated to the latest version of GNURADIO and UHD and installation went smooth. I assigned the IPs to each device, set the corresponding ethernet ports and confirmed that every device is detected. See here

> uhd_find_devices
linux; GNU C++ version 4.4.5 20101112 (Red Hat 4.4.5-2); Boost_104100; UHD_0001.20101124180824.2568efd

--------------------------------------------------
-- UHD Device 0
--------------------------------------------------
Device Address:
    type: usrp2
    addr: 192.168.20.2
    name:
    serial: 00:50:c2:85:39:95


--------------------------------------------------
-- UHD Device 1
--------------------------------------------------
Device Address:
    type: usrp2
    addr: 192.168.10.2
    name:
    serial: 00:50:c2:85:36:8c


After this I tried a simple GRC flow, taking the data and streaming it to two FFT graphs (see flow.png). The settings of the "Multi USRP Source" can be seen in "settings.png". When running the code I don't get any of the FFT sinks showing me something. But there're some warnings(errors?) on the command line from which I don't know their meaning.

Current recv sock buff size: 50000000 bytes
Current recv sock buff size: 50000000 bytes
Set time with unknown pps edge:
    1) set times next pps (race condition)
    2) catch seconds rollover at pps edge
    3) set times next pps (synchronously)

Warning:
    Detected time deviation between board 1 and board 0.
    Board 0 time is 490.997360 seconds.
    Board 1 time is 318.628842 seconds.
   
OOUHD source block got error code 0x1
gr_block_executor: source <gr_block uhd multi_usrp source (1)> produced no output.  We're marking it DONE.


What I am doing wrong? Is there anything that I am missing? Why can't I get the data from the two devices via GRC?

Regards,
  Thomas

-- 
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Dr. Thomas Hobiger
Space-Time Measurement Project
Space-Time Standards Group
New Generation Network Research Center
National Institute of Information and Communications Technology
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flow.png
Description: PNG image

settings.png
Description: PNG image