Siemens 6ES7 321-1BH02-0AA0 Digital Input Module 24V DC

Siemens 6ES7 321-1BH02-0AA0 is a SM321 digital input module for the SIMATIC S7-300 family that provides 16 galvanically isolated DC 24V inputs. The 16 inputs are organized as a single 16-channel bank (DI 16xDC24V, grouping 16) and connect to the PLC backplane via a 20-pin interface, enabling straightforward wiring of field sensors. This backplane-mounted module is designed for standard S7-300 racks and supports extended environmental conditions, making it suitable for industrial installations with demanding ambient requirements. Field wiring typically comprises 24V DC binary sensors such as limit switches and proximity sensors, with each channel delivering a stable logic signal to the CPU and benefiting from consistent input timing across all channels. The part number 6ES7 321-1BH02-0AA0 is documented in Siemens release materials as DI 16xDC24V with galvanic isolation, confirming its role as a direct 24V input interface for PLC programs and its placement within the PCS 7/SIMATIC S7 ecosystem. With its 16-channel footprint and robust isolation, it supports scalable expansion of input points while maintaining noise immunity and reliable signal integrity in industrial automation projects.