"thingSpeakRead Numminutes" is giving different size vectors for different fields | MATLAB IoT Analytics | Forum

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"thingSpeakRead Numminutes" is giving different size vectors for different fields
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November 7, 2020
10:34 am
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November 7, 2020
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I'm sending data from an instrument to this channel: 1135922, then processing it using Matlab Analysis, and writing it on this other channel 929257.

I'm reading the fields' data like this:
[fieldX,timestamps] = thingSpeakRead(readChannelID, 'Fields',1,'Numminutes',6,'ReadKey', readAPIKey)
fieldY = thingSpeakRead(readChannelID, 'Fields',2,'Numminutes',6,'ReadKey', readAPIKey)
fieldZ = thingSpeakRead(readChannelID, 'Fields',3,'Numminutes',6,'ReadKey', readAPIKey)
eulerR = thingSpeakRead(readChannelID, 'Fields',4,'Numminutes',6,'ReadKey', readAPIKey)
eulerP = thingSpeakRead(readChannelID, 'Fields',5,'Numminutes',6,'ReadKey', readAPIKey)
eulerY = thingSpeakRead(readChannelID, 'Fields',6,'Numminutes',6,'ReadKey', readAPIKey)
temperature = thingSpeakRead(readChannelID, 'Fields',7,'Numminutes',6,'ReadKey', readAPIKey)

The problem is, that every so often, the vectors end up with different number of elements with respect to each other. So, I end up having gaps in the processed data.

I have checked the data that I'm receiving from the instrument, and there is no gaps on the data. Every "timestamp" has ALL 8 fields of data, but Matlab Analysis is not reading it properly.

I wasn't having this problem with the free 15-seconds update rate, but when I upgraded to the paid license and started transmitting at about 2-3 sec, I started having the problem.

I would appreciate any help, as this is for my thesis and my deadline is in 2 weeks.

December 15, 2020
7:10 am

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March 7, 2017
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FYI, MATLAB answers is the preferred location for ThingSpeak Community support.

I've had this problem when reading from the MathWorks weather station. Since you are writing faster, there is probably a larger likelihood that there are different numbers of entries in a given number of minutes. Have a look at the read temperature in three days example in the documentation, that example shows a way to make the number of entries independent of the time range. https://www.mathworks.com/help/thingspeak/Compare-Temperature-Data-from-Three-Different-Days.html

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