update main, check user input

main.py

@@ -39,7 +39,10 @@ while is_log_heater != 0 and is_log_heater != 1:
         print("1 = measuring calorimeter constant")
         print()
 
-    is_log_heater = int(input("measurement process = "))
+    try:
+        is_log_heater = int(input("measurement process = "))
+    except ValueError:
+        is_log_heater = 2
 
 # Read the metadata necessary to control test rig from the setup file.
 metadata = m_json.get_metadata_from_setup(path_setup)