Voltcraft top hat rail ac meter vsm 102 voltcraft vsm 102 zhler p the voltcraft vsm 102 is a compact electronic active energy meter for use in three phase grids with a neutral conductor the application range is in the low voltage level for recording energy purchases the meter also has an s0 interface and a serial rs485 interface that may be used for reading the meter reading and various performance data the meter is compatible with the smart metering system vsm 201 gateway p voltcraft