
Digital modules
4.12 Digital input module SM 421; DI 16 x UC 120/230 V (6ES7421-1FH20-0AA0)
S7-400 Automation System Module Data
Reference Manual, Edition 09/2009, A5E00850736-06
135
Wiring and block diagram of the SM 421; DI 16 x UC 120/230 V
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Process Module
Data register and bus control
Figure 4-9 Wiring and block diagram of the SM 421; DI 16 x UC 120/230 V
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