How accurate is the power measurement of the dSM? digitalSTROM Support October 12, 2018 08:37 Updated Follow The specified measurement accuracy is: +/- 5 % (I ≥ 0.02 x I nominal) real power. Related articles How often are the energy readings updated in the dSM? What does the dSM measure: Active power or apparent power? Is the dSM equipped with surge protection? Why are there only digitalSTROM meters dSM up to 16A? A dSM does not respond although the LED is on