Siemens 6ES7521-7EH00-0AB0 SIMATIC S7-1500 DI 16x24...125V UC HF PLC I/O Module

The Siemens SIMATIC S7-1500 digital input module DI 16x24...125V UC HF (6ES7521-7EH00-0AB0) reads 16 channels at 24 V, 48 V, or 125 V AC or DC, grouped in 1, with a parameterizable input delay from 0.05 ms to 20 ms. It also supports 2 channels of up to 6 kHz counting, with front connectors ordered separately.

Technical Specifications

Selection Notes

The UC (universal current) rating means the same module accepts 24 V, 48 V, or 125 V, AC or DC, on its inputs without reconfiguration, so one part number covers mixed-voltage field wiring. HF (high feature) status adds a 2-channel, 6 kHz counter function on channels 0 and 1 on top of standard discrete input duty, and the parameterizable input delay from 0.05 ms up to 20 ms trades noise immunity against response speed per channel group. Front connectors, screw-type or push-in, are ordered separately - factor that into the bill of materials.

Applications

Field-level digital sensing across relay contacts, limit switches, and proximity sensors wired at 24-125 V, with the 6 kHz counter channels handling low-speed flow meters or encoder pulse counting alongside standard discrete I/O.