Problem with the error ValueError: can not convert the string to float: in python

Dude, you have to make sure that there is only one digital channel to convert. Ex

float (# 12 .34))

In this way, it works normally. If there are letters together, you must remove them and leave only the numbers to perform the conversion. Try to debug what returns the value you are trying to convert, if you only have numbers in the format string that will work normally.