The EL3122 analog input terminal processes signals in the range between 4 and 20 mA. The current is digitised to a resolution of 16 bits and is transmitted, electrically isolated, to the higher-level automation device. The input channels of the EtherCAT Terminal have differential inputs and possess a common, internal ground potential. The EL3122 combines two channels in one housing. An open lead or overload condition are detected. The terminal status is relayed to the controller via the E-bus. The EtherCAT Terminal indicates its signal state by means of light emitting diodes. The error LEDs indicate an overload condition and a broken wire.

https://www.beckhoff.com/vi-vn/products/i-o/ethercat-terminals/el3xxx-analog-input/el3122.html