SUP-DM3000 Membrane type dissolved oxygen is the measure of oxygen dissolved in an aqueous solution. Polarographic measurement principle, the dissolution value depends on the temperature of the aqueous solution, pressure and salinity in solution. The meter uses a liquid crystal display for measuring and displaying DO and medium temperature values, with analog and digital signal outputs and control functions. Features Range: 0-20mg/L,0-200%,0-400hPaResolution:0.01mg/L,0.1%,1hPaOutput signal: 4~20mA; Relay; RS485Power supply: AC220V±10%; 50Hz/60Hz