How to use 'rangeMin' and 'rangeMax'?

I tried to use it this way but I didn’t see any results in the gauges I tried to create, it always keeps the maximum value 65535.

 <value name="Sensor Temperatura LM35 2" offset="4" length="2"conversion="V*0.4821+2"rangeMin="0" rangeMax="150"></value>

Those values sets the recommended range to the value which you see when you attach a gauge to the input. It does not ‘fix’ the range to this so if you have modified the range in ‘Input & Values’, these values have no meaning after that.