I can check back bit later, when I can properly look them up, but quickly responding - they are not mandatory for basic usage. They are needed if you have a need to aggregate/filter data, in which case (when properly set), you can focus on certain entity or category.
Of course if the regexp is "too wide", it might interfere with more categorized ones, but if you add it as last, it shouldn't mess around too much.
Did you get the readings to work in your graphs as expected, are the values available properly?
Of course if the regexp is "too wide", it might interfere with more categorized ones, but if you add it as last, it shouldn't mess around too much.
Did you get the readings to work in your graphs as expected, are the values available properly?