Tkinter: How to assign calculated value to a Label

[LoneStar]

Okay. I got it to work:

1. I removed the "while true" statement in the CycleCO2 function.
2. I replaced the following statement:
valCo2 = tk.Label(frame2, text = str(co2) )

with

 self.valCo2.config(text = co2)

Now it displays the value when click the "Start" button.