Siemens Simatic S7-400 - Manual (Page 163)

Digital Modules
4-41
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
4.11 Digital Input Module SM 421; DI 16 120 VAC
;
(6ES7421-5EH00-0AA0)
Characteristics
The SM 421; DI 16 120 VAC has the following features:
• 16 inputs, isolated
• 120 VAC rated input voltage
• Suitable for switches and two-wire proximity switches
(BEROs, IEC 61131; type 2)