4-channel digital input terminal, TwinSAFE, 24 V DC EL1904
Diagnostic 4
Diagnostic 2
Input 4
Input 2
Diagnostic 3 
Diagnostic 1 
Input 3 
Input 1 
Power contact
+24 V
Power contact 0 V
Input 1+
Input 1–
Input 3+
Input 3–
Input 2+
Input 2-
Input 4+
Input 4–
Top view 
Contact assembly 

EL1904 | 4-channel digital input terminal, TwinSAFE, 24 V DC

The EL1904 EtherCAT Terminal is a digital input terminal for sensors with potential-free contacts for 24 V DC. The EtherCAT Terminal has four fail-safe inputs. The EL1904 meets the requirements of IEC 61508 SIL 3 and DIN EN ISO 13849 PL e.

Technical data EL1904
Connection technology 1-/2-wire
Safety standard DIN EN ISO 13849-1:2008 (Cat 4, PL e) and IEC 61508:2010 (SIL 3)
Number of inputs 4
Protocol TwinSAFE/Safety over EtherCAT
Status display 8 LEDs: 1 per input, 4 diagnostic
Response time typ. 4 ms (read input/write to E-bus)
Current consumption E-bus approx. 200 mA
Fault response time ≤ watchdog time (parameterisable)
Bit width in the process image input: 6 byte; output: 6 byte
Supply voltage 24 V DC (-15 %/+20 %)
Nominal voltage 24 V DC (-15 %/+20 %)
Special features 4 safe inputs
Weight approx. 50 g
Operating/storage temperature -25…+55 °C/-40…+70 °C
Permitted degree of contamination 2
Climate class EN 60721-3-3 3K3
EMC immunity/emission conforms to EN 61000-6-2/EN 61000-6-4
Vibration/shock resistance conforms to EN 60068-2-6/EN 60068-2-27
Installation position horizontal
Protection class IP 20
Approvals CE, UL, Ex, TÜV SÜD