Missing data


PaulC

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I'm sampling 16 channels at 50 Hz on a LabJack U6. There are a few times that data is simply not recorded for 200ms. Only the second colum is important, which shows time since acquisition start. What are possible causes for the jump from 2.54 to 2.73 (row 3 to row 4)? This happens only once or twice per 10 second test.

  global time	DataTime
40137.56347	2.5065	  42.3	38.25	...
40137.56347	2.5265	  42.3	38.25	...
40137.56347	2.5466	  42.3	38.24	...
40137.56347	2.7346	  42.3	38.25	...
40137.56347	2.7495	  42.3	38.25	...

A few other times there are smaller dropouts, such as the 40ms drop from row 2 to row 3.

40137.56346	1.6866	42.3	38.24
40137.56346	1.7068	42.3	38.25
40137.56346	1.7426	42.3	38.24
40137.56346	1.7587	42.3	38.25

But 95% of the time many seconds go by with no loss in data. Is this a logging issue, a DAQfactory issue, or a Labjack issue? A plot of some data is included, with dropped data circled in red.

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To know what is really going on, I'd need to see the same examples, but with the first Time column displayed without Excel time enabled. So instead of 40137 you'd get a something like 1.25 billion. Then I can tell whether the problem is in the time stamp on the data, or in how you are calcing the dT values.

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