The digital EL1859 EtherCAT Terminal combines eight digital inputs and eight digital outputs on a single device. The signal state of the channels is indicated by LEDs. The reference ground for all inputs is the 0 V DC power contact; the outputs are fed via the 24 V power contact.

Special features:

• compact design through the combination of inputs and outputs in one terminal
• no bouncing due to mechanical switches thanks to 3 ms input filter
• short-circuit proof outputs protected against reverse polarity with output current up to 0.5 A
• tool-free connection by direct plug-in technique for solid wire conductors

https://www.beckhoff.com/vi-vn/products/i-o/ethercat-terminals/el1xxx-digital-input/el1859.html