Digital modules
3.11 Digital input module SM 321; DI 16 x 24 VDC; with hardware and diagnostic interrupts (6ES7321-7BH01-0AB0)
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ
81
Wiring and block diagram of SM 321; DI 16 x DC 24 V
Status displays - green
Error displays - red
Wiring diagram of the redundant sensor supply
The figure below shows how an additional redundant voltage source can be used to power
sensors using Vs.
Figure 3-4 Wiring diagram of the redundant supply of sensors of SM 321; DI 16 x DC 24 V