Product Overview
Technical Summary
| Parameter | Value |
|---|---|
| Digital input channels | 16 |
| Input voltage type | AC/DC |
| Rated input voltage | 230 V; 120/230 V UC (47 … 63 Hz) |
| Signal "0" voltage | 0 to 40 V AC / -40 to +40 V DC |
| Signal "1" voltage | 74 to 264 V AC; 80 to 264 V DC, -80 to -264 V |
| Potential separation | Between channels and between channels and backplane bus; in groups of 4 |
| Input current from backplane bus | 5 V DC, max. 80 mA |
| Power loss | 12 W, typ. |
| Status indicator | Digital input status, green LED |
Applications
- Digital signal acquisition: The module provides isolated digital input acquisition for AC/DC signals.
Key Features
- 16 isolated digital inputs: The SM 421 module has 16 digital inputs, with all 16 inputs simultaneously controllable.
- AC/DC input voltage: Input voltage is AC/DC, with a rated value of 230 V and 120/230 V UC at 47 … 63 Hz.
- Signal voltage ranges: Signal "0": 0 to 40 V AC / -40 to +40 V DC. Signal "1": 74 to 264 V AC; 80 to 264 V DC, -80 to -264 V.
- Electrical isolation: The digital inputs have potential separation between channels and between the channels and the backplane bus. Isolation is tested with 1 500 V AC.
- Status indication: A green LED provides digital input status indication. The diagnostics function is not available.
- Module dimensions and weight: The module measures 25 mm wide, 290 mm high, and 210 mm deep, with an approximate weight of 650 g.
Frequently Asked Questions
1. How many digital inputs does Siemens 6ES7421-1FH20-0AA0 have?
It has 16 digital inputs, and all 16 inputs are simultaneously controllable.
2. Which input voltage ranges does this module support?
It supports AC/DC input voltage. Signal "0" is 0 to 40 V AC / -40 to +40 V DC; signal "1" is 74 to 264 V AC and 80 to 264 V DC, -80 to -264 V.
3. Does the module provide electrical isolation?
Yes. The digital inputs are separated between channels and between the channels and the backplane bus, in groups of 4. Isolation is tested with 1 500 V AC.
4. Does Siemens 6ES7421-1FH20-0AA0 have diagnostics?
The diagnostics function is not available, but a green LED indicates digital input status.
