Siemens Simatic S7-400 - Manual (Page 166)

Digital Modules
4-44
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
4.12 Digital Input Module SM 421; DI 16 24/60 VUC;
(6ES7 421-7DH00-0AB0)
Characteristics
The SM 421; DI 16 24/60 VUC is characterized by the following features:
• 16 inputs, individually isolated
• Rated input voltage 24 VUC to 60 VUC
• Suitable for switches and two-wire proximity switches (BEROs)
• Suitable as active high and active low input
• Group error display for internal faults (INTF) and external faults (EXTF)
• Programmable diagnostics
• Programmable diagnostic interrupt
• Programmable hardware interrupt
• Programmable input delays
The status LEDs indicate the process status.