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? How often are the energy readings updated in the dSM? A dSM does not respond although the LED is on Is there a software for commissioning a digitalSTROM system?