Calculate Dew point Channel 1120609

Hi there! My channel is 1120609 and I made the dew point calculate but it’s working only a few minutes. How can I make this to work all the time?

[John D'Errico]

How is this a question about MATLAB?

[Marcio Lopes]

Hi John, I typed the code below and I ask for help. It's not working all the time.

Answer 1

[Vinod]

Can you share your MATLAB code that is doing the dew-point calculation on ThingSpeak? Remember to redact or replace your channel's API keys in the code snippet with a placeholder like "XXXXX".

[Marcio Lopes]

Hi Vinod, thank you for your reply. I would apreciatte if you help me. Follow attached and below the Matlab code. I would show the dewpoint in Celsius Degrees. Thank you.

%MatLab code
readChId = 1120615;
writeChId = 1120609;
writeKey = '_____XXXXX____';
[temp,time] = thingSpeakRead(readChId,'Fields',1,'NumPoints',20);
humidity = thingSpeakread(readChId,'Fields',2,'NumPoints',20);
tempC = temp;
b = 17,62;
c = 243,5;
gamma = log(humidity/100) + b*tempC./(c+tempC);
dewpoint = c*gamma./(b-gamma);
dewpointF = (dewpoint*1.8) + 32;
thingSpeakWrite(writeChId,[temp,humidity,dewpoint],'Fields',[1,2,3],...
'TimeStamps',time,'WriteKey',writeKey);

[Vinod]

You need to associate this code to a TimeControl app on ThingSpeak which will execute the code on a schedule. You probably want to modify "NumPoints" to "NumMinutes" parameter to thingSpeakread to a value less than the TimeControl frequency. Then, your channel specified in writeChId will be updated every time the TimeControl runs.

[Marcio Lopes]

Thank you Vinod. Now it's working very well.

Thanks a lot.