Siemens Simatic S7-400 - Manual (Page 178)

Digital Modules
4-56
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
4.15 Digital Input Module SM 421; DI 32 120 VUC
;
(6ES7421-1EL00-0AA0)
Characteristics
The SM 421; DI 32 120 VUC is characterized by the following features:
• 32 inputs, isolated
• Rated input voltage 120 VAC/VDC
• Suitable for switches and two-wire proximity switches