Siemens 6ES7521-1BH00-0AB0 Digital Input Module

Siemens 6ES7521-1BH00-0AB0 is a SIMATIC S7-1500 digital input module that provides 16 channels for 24 V DC signals in a High Feature (HF) configuration, designed to expand a PLC’s digital input capacity. The 16 inputs are organized in a single 16-channel block, with two inputs that can be used as counters for counting events in automation tasks. It supports an input delay of 0.05 to 20 ms and implements IEC 61131 Type 3 input behavior, with built‑in diagnostics and hardware interrupts to help monitor and respond to signal changes. A front connector for wiring—available with screw terminals or push-in design—must be ordered separately, as it is not included with the module. This HF DI module is intended for integration into SIMATIC S7-1500 systems, enabling reliable, timestamped digital input capture from sensors and switches in manufacturing and process-control environments.