07-10-2018 10:06 AM
Hi,
while trying to run the example "RFSA Stream IQ to Disk.vi" i get an error
after a few seconds with the PXIe-5646R and with the settings in the main vi:
IQ Rate: 125 M S/S
Total Samples: 12500000
Max. Samples per Block: 1000
-----
Error: -369019
in niRFSA Fetch IQ (1DI16).vi :
"The requested data has been overwritten in memory.
Therefore, it is no longer available for fetching."
-------
-What does this mean?
(-Is there a buffer underrun? -Ho can i appropiatly configure it to run? )
07-12-2018 12:36 AM
Hi PXIeuser !
The message mean the data in memory has not been read fast enougth and the new data coming from the digitizer has overwritten the old data.
I thin you must increase the number of sample per read.
1000 sample per read @ 125 Ms/s = 125000 loops per second to read each buffer ! Impossible on host computer !
try to read a power of 2 to match with the bus size and about 2 mega samples ou 4 MS.
Regards
07-12-2018 01:53 AM
Hi,
thanks for your help:
i've tried Max. Samples per Block with
4194304 (= 2^22 Samples =approx. 4 MS)
and
2097152 (=2^21 Samples = approx. 2 MS),
but i get the same error.
My System:
Chassis: NI PXIe-1082 Controller: NI PXIe-8880 RAID: NI HDD-8261 VST: NI PXIe-5646R
OS: Win 10 Pro LabView 2017, 32 Bit
;-(
07-12-2018 02:13 AM
Ok i don't look at your example before but now i can tell you this VI is not the good way for high data throughput.
Give a try to this example : http://www.ni.com/example/30895/en/
Maybe you will have to modify some values but it is the good architecture to record data.
To resume, you must look at the fetch backlog which is the amount of data available on the onboard memory and fetch data when the desired number of sample is reached.
Oh an other thing : don't try to stream back data to VST with RFSG, it is not supported !
Regards
07-16-2018 12:13 PM
If you're trying to stream full rate to disk, then you should consider this example.
07-17-2018 01:02 AM
Many thanks!!!
This example ("Streaming Host Example for the NI PXIe-5644R/45R/46R ")
works!
11-24-2021 11:43 PM
Hii,
I hope you are doing good.
I don't find the "RFSA Sream IQ to disk" Example. Can you provide me with that?
I need to stream IQs directly from the device buffer to the hard disk bypassing the Windows, LabVIEW, and TDMS buffers. Hope this example will help.
Thank You.