The EL1889 digital input terminal acquires the binary 24 V control signals from the process level and transmits them, in an electrically isolated form, to the higher-level automation unit. The EtherCAT Terminal has 16 channels, whose signal states are indicated by LEDs. The power contacts are connected through. With the EL1889, the reference ground for all inputs is the 24 V power contact.

Special features:

• ground switching
• no bouncing due to mechanical switches thanks to 3 ms input filter
• tool-free connection by direct plug-in technique for solid wire conductors
• space-saving use in the control cabinet
• direct connection of multi-channel sensors in 1-wire connection technology in the smallest space

https://www.beckhoff.com/vi-vn/products/i-o/ethercat-terminals/el1xxx-digital-input/el1889.html