4-channel digital input terminal 24 V DC, filter 1 µs, with timestamp EL1254
Signal LED 4
Signal LED 2
Signal LED 3 
Signal LED 1 
Power contact
+24 V
Power contact 0 V
Input 1
Input 3
Input 2
+24 V
0 V
Input 4
Top view 
Contact assembly 
XFC – eXtreme Fast Control

EL1254 | 4-channel digital input terminal 24 V DC, filter 1 µs, with timestamp

The EL1254 digital input terminal is the 4-channel variant of the EL1252. It acquires the fast binary control signals from the process level and transmits them, in an electrically isolated form, to the controller. The signals are furnished with a timestamp that identifies the time of the last edge change with a resolution of 1 ns. This technology enables signals to be traced exactly over time and synchronized with the distributed clocks across the system. With this technology, machine-wide parallel hardware wiring of digital inputs or encoder signals for synchronization purposes is often no longer required.

Technical data EL1254
Connection technology 4-wire
Specification similar to EN 61131-2, type 3, “0”: -3…5 V DC, “1”: 11…30 V DC, typ. 3 mA input current
Number of inputs 4
Nominal voltage 24 V DC (-15 %/+20 %)
“0” signal voltage -3…+5 V (similar to EN 61131-2, type 3)
“1” signal voltage 11…30 V (similar to EN 61131-2, type 3)
Input current typ. 3 mA (similar to EN 61131-2, type 3)
Input filter typ. < 1 µs
Resolution timestamp 1 ns (channel 0/1)
Precision of timestamp in the terminal 10 ns (+ input delay)
Distributed clock precision << 1 µs
Input delay TON/TOFF < 1 µs
Distributed clocks yes
Time resolution signal 1 ns
Current consumption power contacts typ. 20 mA + load
Current consumption E-bus typ. 80 mA
Electrical isolation 500 V (E-bus/field potential)
Bit width in the process image 2 inputs + 36 byte timestamp
Configuration no address or configuration setting
Special features timestamping, latch last edge
Weight approx. 55 g
Operating/storage temperature 0…+55 °C/-25…+85 °C
Relative humidity 95 %, no condensation
Vibration/shock resistance conforms to EN 60068-2-6/EN 60068-2-27
EMC immunity/emission conforms to EN 61000-6-2/EN 61000-6-4
Protect. class/installation pos. IP 20/variable
Approvals/markings CE
Further information  
XFC eXtreme Fast Control Technology