Siemens SM 321 digital input module, 16 x 24 V DC, for the S7-300 family, provides 16 optically isolated inputs in a 20-pin front connector (order number 6ES7 321-1BH02-0AA0). Designed for industrial automation, it reads 24 V DC signals from sensors and switches and plugs into the S7-300 backplane as a standard SM321 DI module. With 16 channels in a compact form factor, it enables grouped input handling for status indications and control logic while maintaining field-to-backplane isolation.
