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PS6000_LOST_DATA

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PS6000_LOST_DATA

Postby LGMPICO » Fri Dec 16, 2011 9:31 am

Hello,

I use a ps6000 oscilloscope in streaming mode and I can check from time to time that some data are missing.
I know this is unavoidable but I wonder if the flag PS6000_LOST_DATA has been implemented or not. On one end I never see the code -32768 in the data flow (even when data are clearly missing) and on the other end the PS6000_LOST_DATA is mentionned in the PicoScope 6000 Series Programmer's Guide but only in the index on page 98.
It would be very usefull for me to check on line if data are missing or not.

Thanks in advance

Best regards
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Re: PS6000_LOST_DATA

Postby Martyn » Tue Dec 20, 2011 1:06 pm

LOST_DATA is not implemented in the 6000 series drivers, the reference in the manual should have been removed.

I would be more interested in looking at the reasons why you are losing data in the first place and see if it is possible to remove these.
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Re: PS6000_LOST_DATA

Postby LGMPICO » Mon Jan 16, 2012 4:46 pm

Hello,

Thanks for your reply. It seems that I can read continuously (for several minutes) the 4 channels at a 1MHz sampling rate and when I turn this rate to 2 MHz data are lost after a “short” time (20 to 30 seconds). In fact my requirement is to increase the sampling rate up to 10 MHz and to read the 4 channels of the PS6000. A run duration can reach 15 minutes leading to a very large amount of data. Only a small a part in time of the signals is relevant (only 100µs each 4ms). A clock signal is available to trigger on the PS6000 each 4ms. I would like to know if it is possible to reduce the data flow on the USB by catching the 4 channels for 100µs at each trigger occurrence. Moreover we want to run continuously without losing any relevant data (100 µs each 4ms).
By the way I have noticed that Labview 8.5 crashes often when I run the VIs provided in the
Development Kit. Is there any problem with the dll I use (1.0.0.229)?

Thanks in advance

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Re: PS6000_LOST_DATA

Postby Martyn » Tue Jan 17, 2012 10:46 am

Which variant of the 6000 series do you have ?
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Re: PS6000_LOST_DATA

Postby LGMPICO » Tue Jan 17, 2012 12:35 pm

PS6403
SN AY432/020
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Re: PS6000_LOST_DATA

Postby Martyn » Thu Jan 19, 2012 11:15 am

That's a pity, if you had a 6404 then you would be able to use RapidBlock mode to do this. Unfortunately the 6403 does not permit you to set sufficient memory segments to capture 15 minutes of data and would only be able to handle about 4 minutes.

In your scenario you are looking to capture 1000 samples of data for each channel and repeat this every 4ms for the duration of the test. You may be able to use streaming mode and set it up to capture 1000 samples to a buffer and set it to auto stop and flag when it is done. Once your application sees the flag you will need to restart streaming but capture the data to a new buffer. Whilst the driver is capturing the next stream your application can process the data from the first buffer. The key will be to restart the stream as soon as possible after the first stream is complete to try and meet the 4ms repeat nature of the data, hence the use of two, or more, sets of buffers.
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