Error -1074118649 occurred at niUSRP Fetch Rx Data (2D CDB).vi

[andy5868]

hi

when i was trying the example of the NI USRP which is 'niUSRP EX Rx Multiple Synchronized Inputs (MIMO Expansion)', a error came out which is 

Error -1074118649 occurred at niUSRP Fetch Rx Data (2D CDB).vi

A stream command was issued in the past.

can anyboay help me to solve the problem?

thank you very very much 

andy 

[Aristocrate · Accepted solution]

Hi andy,

what you need doing is inverting the oder in which the VIs niUSRP Set Time.vi and niUSRP Configure Trigger.vi a1.1ppear. First time setting then configure trigger. The example works properly with version 1.1, since you are using the version 1.2, that change have to be made.

In the example you set the clock to reference time (start time =0) although you had already triggered the reception. Thus, received samples will be acquired with later timestamp where the error.

Best regards

[mustermann_1415]

Hello everyone,

at the moment I try to built a 2x4 MIMO by expanding the 2x2 MIMO example. I already changed the Alamouti block for 4 receive antennas. I am pretty sure this works well. But I got the problem, that it occurres the error at niUSRP Fetch RX DATA (2D CDB).vi "A stream command was issued in the past."

I got 4 USRPs connected by MIMO and ethernet to a switch. I have changed in the subAsyncMulti-ChannelTransceiver(NIUSRP).vi so that I just copied the receive block. The second receive block works with the IP - adresses from the other two USRPs. In the end I insert one array into the another. With this array I go on.

Might the problem just be not using a external synchronizing clock for the USRPs or can I just not built it up like this way?

Sincerly