fixed errors while specifing path with f-strings

hp4155/measurements.py

@@ -213,9 +213,9 @@ def ctlm(field_name ='M00',time='MED',start=-50*10**(-3),stop=50*10**(-3),step=1
         date = str(datetime.today().replace(microsecond=0))
         
         file_name = f"{field_name}_CTLM_{j+1}.txt"
-        #path = f"\\FILESERVER\public\Datentransfer\Asonitis, Alexandros\{file_name}"
+        path = f"\\FILESERVER\public\Datentransfer\Asonitis, Alexandros\_{file_name}"
         #export DataFrame to text file (keep header row and index column)
-        with open(file_n, 'a') as f:
+        with open(path, 'a') as f:
         f.write('title\n')
         df_string = df.to_string()
         f.write(df_string)