Hi piajola,
Thank you very much for your help. It works now! Great idea to put both variables in one string. The solution is:
String analogValue = String(Wert1, DEC);
String analogValue2 = String(Wert2, DEC);
senden="&field1="+analogValue+"&field2="+ analogValue2;
and after this you can just call the “updateThingSpeak(senden);” function.
I am really happy now. Thank you again and great job.