The UMD 704 is a compact power quality meter for online measurement for DIN rail mounting. It measures 4-phase current and voltage with up to three tariffs in 6-quadrant operation and work in class 0.2s, as well as all usual network sizes, eg harmonics up to the 50th harmonic. Digital inputs / outputs and a serial RS485 interface are integrated. The UMD 704 can also be equipped with M-Bus interface.