Features:
- Sixteen individually isolated channels accept AC or DC field states across the UC 24–60 V design.
- Four selectable input delays link response time to the supported field-cable length.
- Configurable diagnostics and interrupts operate beside separate channel and fault indicators.
Siemens 6ES7421-7DH00-0AB0 concentrates isolated multi-voltage input acquisition in one S7-400 SM 421 assembly.
Its reading-polarity and sensor settings define how connected field circuits are referenced before their states reach the controller.
Delay, diagnostic, and interrupt parameters keep input filtering, fault reporting, and event handling as separate functions.
Apter Power assists with pricing and access to official manufacturer documentation for Siemens 6ES7421-7DH00-0AB0 SIMATIC S7-400 SM 421 Digital Input Module.
Siemens 6ES7421-7DH00-0AB0 SIMATIC S7-400 SM 421 Digital Input Module Manuals, Datasheets, Links
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
6ES7421-7DH00-0AB0 Channel Organization
- Channel separation: All 16 digital inputs are isolated individually.
- Signal type: The same input design accepts AC or DC field states.
- Reading polarity: P-reading and M-reading modes define the field reference.
- Sensor connection: Switch contacts and two-wire proximity sensors are supported.
6ES7421-7DH00-0AB0 Input Filtering
- Available settings: Input delay can be set to 0.5, 3, 10, or 20 ms.
- Parameter method: The delay is assigned through module parameterization.
- Shortest response: The 0.5 ms setting carries the 100 m conductor limit.
- Extended wiring: The longer settings permit the documented shielded and unshielded cable runs.
6ES7421-7DH00-0AB0 Diagnostic Paths
- Group diagnostics: Module diagnostic evaluation can be enabled by parameterization.
- Diagnostic interrupt: A diagnostic event can be transferred through the S7-400 interrupt path.
- Hardware interrupt: Input events can use the separately configured hardware-interrupt path.
- Front indication: INTF and EXTF distinguish internal from field-side fault classes.
6ES7421-7DH00-0AB0 Field Connections
- Contact inputs: Switch contacts connect directly to the input circuits.
- Two-wire devices: Proximity sensors must remain within the specified quiescent-current limit.
- Voltage bands: AC and DC operation use their stated signal-zero and signal-one ranges.
- Cable boundary: The permissible conductor length depends on the selected input delay.