Product information
Overview
Applications
- Wire-break monitoring: The module supports wire-break monitoring through its encoder connection and wire-break diagnosis at I> 0.7 mA.
Key Features
- 16 isolated digital inputs: The SM 421 module has 16 isolated digital inputs, with all 16 inputs simultaneously controllable.
- AC/DC input voltage: Input voltage type is AC/DC. Rated input value is 24 V; 24 V UC to 60 V UC at 47 … 63 Hz.
- Signal thresholds: Signal "0": -6 to +6 V DC/ 0 to 5 V AC. Signal "1": 15 to 72 V DC; -15 to -72 V DC; 15 to 60 V AC.
- Parameterizable timing and diagnostics: Standard inputs are parameterizable, with rated input delay values of 0.5 ms; 0.5 / 3 / 10 / 20 ms. Diagnostics, diagnostic alarms and hardware interrupts are parameterizable.
- Encoder and cable support: The module supports 2-wire sensors, with permissible quiescent current of 0.5 mA; 0.5 to 2 mA. Shielded cable length is up to 1 000 m.
- Electrical separation and monitoring: Digital inputs are electrically separated between channels and from the backplane bus. Separation is provided in groups of 1, and wire-break detection is available at I> 0.7 mA.
Technical Summary
| Product lifecycle | Announcement of product phase-out |
|---|---|
| Module type | SIMATIC S7-400, digital input SM 421 |
| Digital inputs | 16 isolated |
| Input voltage | AC/DC; 24 V UC to 60 V UC (47 … 63 Hz) |
| Simultaneously controllable inputs | 16 |
| Signal "0" | -6 to +6 V DC/ 0 to 5 V AC |
| Signal "1" | 15 to 72 V DC; -15 to -72 V DC; 15 to 60 V AC |
| Input delay | 0.5 ms; 0.5 / 3 / 10 / 20 ms |
| Diagnostics and alarms | Parameterizable diagnostics, diagnostic alarm and hardware interrupt |
Frequently Asked Questions
What is the exact Siemens module type?
It is the Siemens 6ES7421-7DH00-0AB0 SIMATIC S7-400 SM 421 digital input module.
How many digital inputs does the module have?
It has 16 isolated digital inputs, and all 16 inputs are simultaneously controllable.
What input voltage does it support?
It supports AC/DC input. The rated value is 24 V; 24 V UC to 60 V UC at 47 … 63 Hz.
What diagnostics are available?
Diagnostics, diagnostic alarms and hardware interrupts are parameterizable. Wire-break detection is available at I> 0.7 mA.
What is included in this configuration?
It is without a channel fault indicator F (red).
