ThingSpeak

I am trying to send data to a channel using thingspeak writefield and I keep getting an error no matching function... On reading the documents I am having a problem with "Write key". I can find no info on write key. what is it? ThingSpeak.writeField Write key Log into thingSpeak, go to my channels, select your channel and then click the API keys tab. See this page in the doc. Syntax thingSpeakWrite(channelID,data,'WriteKey','channel write API key') thingSpeakWrite(___,Name,Value) response = thingSpeakWrite(___) The above is taken from Thingspeak docs. The fourth item in the package is Wwrite key" That is the issue. Any help will be appreciated Log into thingSpeak, go to my channels, select your channel and then click the API keys tab. See this page in the doc. function write key

I want to write data along with time into a single field of thingspeak. Here is my code : Date=datetime(2019,9,20,0,0,0) tStamps=[Date-caldays(5):caldays(1):Date]' dataField1=[50,15,16,55,60,75]' channelID=XXXXXX; writeKey= ' XXXXXXXXXXXXXXXX'; readKey='XXXXXXXXXXXXXXXX'; thingSpeakWrite(channelID,dataField1,'WriteKey',writeKey) [A,B]=thingSpeakRead(channelID,'ReadKey',readKey) The output is : Date = datetime 20-Sep-2019 00:00:00 Output Date = datetime 20-Sep-2019 00:00:00 tStamps = 6×1 datetime array 15-Sep-2019 00:00:00 16-Sep-2019 00:00:00 17-Sep-2019 00:00:00 18-Sep-2019 00:00:00 19-Sep-2019 00:00:00 20-Sep-2019 00:00:00 dataField1 = 50 15 16 55 60 75 A = 50 B = datetime 26-Feb-2020 01:53:36 Thus, only one element of the dataField1 and tStamps is shown in the read output. Is there any error in the code?

[pressure,time] = thingSpeakRead(readChId,'Fields',1,'NumPoints',100); Hi everyone, I'm using this variable in a program code and I'd like to know what expression 'NumPoint' does to it. What I want to do is to read a signal now at timeline and another point a few minutes before the first one to calculate how much litters a machine is produzing tax production. How could I do that? PS: This is the first time I'm using any kind of programming language