What does the dSM measure: Active power or apparent power? digitalSTROM Support October 18, 2018 07:45 Updated Follow The dSM measures active power. Related articles Does a digitalSTROM meter (dSM) have to be reconfigured after an exchange? How accurate is the power measurement of the dSM? dSM(s) are not visible in the configurator How many filters dSF need to be installed? What happens if a dSM is defective?