Hello @Koepel ,
myNex.readNumber() is used for inserting the number of dough balls by Nextion , that once the sensor reads the target number using the ISR "void countingballs()". And I have not written the commands for this in the normal loop function yet.
In addition, I am using the normal Serial port for Nextion screen (pins: 0 and 1) and I am not using the serial monitor.
I got the point of myNex.NextionListen(); function , Thank you.