The Siemens 6ES7521-1BL00-0AB0 is a DI 32x24 V DC HF digital input module for SIMATIC S7-1500 that provides 32 digital inputs at 24 V DC. Inputs are organized in two banks of 16; two inputs can be used as counters, and the module offers an input delay of 0.05–20 ms with IEC 61131 input type 3 support, along with diagnostics and hardware interrupts. A front connector for screw terminals or push-in terminals is ordered separately, making this module a flexible choice for reliable digital input signaling in industrial automation.
