Product information
Overview
Key Features
- 16 isolated digital inputs: The SM 421 module has 16 digital inputs, with 16 inputs simultaneously controllable.
- AC/DC input voltage: Input voltage is AC/DC, with a rated value of 120/230 V UC at 47 … 63 Hz.
- Type 2 input characteristic: The digital inputs have a Type 2 input characteristic according to IEC 61131.
- Channel potential separation: Digital inputs are electrically separated between channels in groups of 4 and from the backplane bus.
- Cable length: Maximum cable length is 1 000 m for shielded cables and 600 m for unshielded cables.
- Input status indication: A green LED provides digital input status indication; the diagnostics function is not available.
Technical Summary
| Product type | SIMATIC S7-400 SM 421 digital input module |
|---|---|
| Digital inputs | 16 isolated DI |
| Input voltage | AC/DC; 120/230 V UC (47 … 63 Hz) |
| Input characteristic | Type 2 according to IEC 61131 |
| Simultaneously controllable inputs | 16 |
| Backplane bus input current | 5 V DC, max. 80 mA |
| Power loss | 12 W, typ. |
| Potential separation | Between channels in groups of 4; between channels and backplane bus |
| Product lifecycle | Announcement of product phase-out |
Frequently Asked Questions
What is Siemens 6ES7421-1FH20-0AA0?
It is a SIMATIC S7-400 SM 421 digital input module with 16 isolated DI.
What input voltage does this module support?
It supports AC/DC inputs with a rated value of 120/230 V UC at 47 … 63 Hz.
Are the digital inputs electrically separated?
Yes. They are separated between channels in groups of 4 and between the channels and the backplane bus.
What should be included in a quotation request?
Include the required quantity, destination, and any project-list context for model-specific verification.
