Comparator of the largest of 2 inputs 0-4/20mA, 0/10V, Pot. Relay output input: 2 x 0-4/20mA or 2 x 0/10V or 2 x Potentiometer isolated output the largest by 1 switched relay (1 preselectable alarm) power supply: 24VDC (20.. 30V) / 115/230VAC-DC (100.. 250V) isolated