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PS3026 streaming vs. block mode

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PS3026 streaming vs. block mode

Postby Guest » Fri Aug 22, 2008 7:42 am

Hi,
I am a total newbie with this subject, so please help me with the following:

I am doing some experiments with streaming and block modes.
I use ps3000_siggen to produce a sine wave for input and try to read values from the scope in either block or streaming mode and compare the results.

For the streaming mode, I use sample_interval_ms = 1, max samples 1024 and windowed = 0

When I call get_values I get something like the following (for 3Hz sine wave)

"-520"
"9882"
"-520"
"9622"
"-520"
"9622"
"-520"
"9362"
"-520"
"9101"
etc

If I run the same scenario with block mode, using timebase 18 (which is the closest one to interval of 1ms? (1310720ns). and oversample = 1

get_times_and_values returns:

time:1966073 value:-11702
time:3276793 value:-11442
time:4587513 value:-10922
time:5898233 value:-10402
time:7208952 value:-9882
etc

The block mode values are something I would expect to see, and streaming mode values are not, can you please tell me what I am doing wrong here. I can post my simple test code if it helps.

BR,
JMa
Guest
 

Re: PS3026 streaming vs. block mode

Postby Guest » Fri Aug 22, 2008 9:41 am

Anonymous wrote:When I call get_values I get something like the following (for 3Hz sine wave)

"-520"
"9882"
"-520"
"9622"
"-520"
"9622"
"-520"
"9362"
"-520"
"9101"
etc


In the above sequence run in streaming mode it seems that every other
value is "crap". The Ext is connected to Channel A. B is not connected.

In the code Channel A is enabled, DCcoupling = FALSE, and range = 6
Channel B is disabled.

I am passing a NULL to get_values for all channels, except A.

Is it so that value[n] is for channel A and [n+1] is for channel B or how should the output be interpreted?

Thanks for advice,
JMa
Guest
 


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