Siemens 6ES7521-1FH00-0AA0 SIMATIC S7-1500 DI 16x230VAC BA 16-Channel PLC I/O Module

The Siemens 6ES7521-1FH00-0AA0 is a SIMATIC S7-1500 digital input module, type DI 16x230VAC BA, providing 16 AC inputs rated 120/230 V AC in groups of four. Input delay is 25 ms and the module reads IEC 61131 type 1 signal levels, with 0 to 40 V AC read as signal 0 and 79 to 264 V AC read as signal 1. Front connectors are ordered separately.

Technical Specifications

Selection Notes

The 79 to 264 V AC signal-1 window and 120/230 V AC rating make this module suitable for reading mains-voltage field devices directly, without an interposing relay, where DC I/O modules cannot be used. Channels are isolated in groups of 4, so a fault or short on one group does not propagate to the other three groups on the same module. The 25 ms input delay filters contact bounce and AC ripple, which is standard for this signal class but not suited to fast pulse counting; a DC input module should be used where sub-millisecond response is required. Front connectors (screw-terminal or push-in) are not included and must be ordered separately.

Applications

Reading 230 V AC field signals such as limit switches, pushbuttons, and relay contacts directly into an S7-1500 station without signal conversion, in cabinets where mains-voltage field wiring is standard practice.