Siemens Simatic S7-400 - Manual (Page 175)

Digital Modules
4-53
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
4.14 Digital Input Module SM 421; DI 16 120/230 VUC;
(6ES7421-1FH20-0AA0)
Characteristics
The SM 421; DI 16 120/230 VUC is characterized by the following features:
• 16 inputs, isolated in groups of 4
• Rated input voltage 120/230 VUC
• Input characteristic curve to IEC 61131; type 2
• Suitable for switches and two-wire proximity switches (BEROs)
The status LEDs indicate the process status.