4-channel digital input terminal, TwinSAFE, 24 V DC KL1904
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 3
Input 2
Input 4
Top view 
Contact assembly 

KL1904 | 4-channel digital input terminal, TwinSAFE, 24 V DC

The KL1904 safety Bus Terminal is a digital input terminal for sensors with potential-free contacts for 24 V DC and has four fail-safe inputs.

Technical data KL1904
Connection technology 2-wire
Number of inputs 4
Protocol TwinSAFE/Safety over EtherCAT
Response time typ. 4 ms (read input/write to K-bus)
Fault response time ≤ watchdog time (parameterisable)
Current consumption power contacts
Current consumption K-bus 48 mA
Installation position horizontal
Safety standard DIN EN ISO 13849-1:2008 (Cat. 4, PL e) and EN 61508:2010 (SIL 3)
Weight approx. 50 g
Protection class IP 20
Approvals/markings Overview of TwinSAFE Certifications (PDF)
Ex-Marking II 3 G Ex nA IIC T4 Gc