The EL3773 and EL3783 power monitoring terminals are designed for state monitoring of 3-phase AC voltage systems. For each phase voltages and currents are sampled as instantaneous values with a resolution of 16 bits:

• for the EL3773 up to 288 Vrms/410 V DC and up to 1 Arms/1.5 A DC
• for the EL3783 up to 400/690 V AC and up to 5 A AC, each with “ExtendedRange”

The six channels are measured simultaneously based on the EtherCAT oversampling principle with a temporal resolution of up to 100 μs (EL3773) or up to 50 μs (EL3783) and passed on to the control system. The control system has sufficient computing power for true RMS or performance calculation and complex custom algorithms for evaluating the measured voltages and currents. Through the oversampling, the terminal is able to measure at significantly shorter intervals than the cycle time of the control system. AC and DC parameters must be connected and measured with a common reference potential. Both of the terminals support distributed clocks and can therefore measure synchronously with other EtherCAT devices. However, they can also be operated without distributed clocks.

The EL3783 offers the “ExtendedRange” feature enabling the use of the full technical measuring range, which equals 130 % of the specified nominal measuring range.

https://www.beckhoff.com/vi-vn/products/i-o/ethercat-terminals/el3xxx-analog-input/el3773.html