The EL1252-0050 digital input terminal acquires the fast binary 5 V control signals from the process level and transmits them, in an electrically isolated form, to the controller. The EtherCAT Terminal has two channels that indicate their signal state via light emitting diodes. The signals are furnished with a time stamp that identifies the time of the last edge change with a resolution of 1 ns. With this XFC technology, signal characteristics can be traced exactly in time and correlated with the distributed clocks system-wide. With this technology, machine-wide parallel hardware wiring of digital inputs or encoder signals for synchronization purposes is often no longer required. The switching thresholds of the input circuit are based on the CMOS level: Signal voltage "0"  2.4 V. The 5 V supply voltage can be generated by the EL9505 power supply terminal and fed into the power contacts.

Special features:

• 5 V inputs
• suitable for particularly fast signals due to very low input delay
• synchronized operation through distributed clocks XFC technology possible
• support of XFC technology timestamp

https://www.beckhoff.com/vi-vn/products/i-o/ethercat-terminals/el1xxx-digital-input/el1252-0050.html