Technical Summary
| Product family | SIMATIC S7-400 |
|---|---|
| Module type | digital input SM 421 |
| Number of digital inputs | 16 |
| Potential separation | between the channels |
| Potential separation from backplane bus | Yes |
| Input voltage type | AC/DC |
| Rated value (UC) | 230 V; 120/230 V UC (47 … 63 Hz) |
| Input characteristic | Type 2 |
| Signal "1" input voltage | 74 to 264 V AC; 80 to 264 V DC, -80 to -264 V |
| Signal "0" input voltage | 0 to 40 V AC/ -40 to +40 V DC |
Key Features
SIMATIC S7-400 digital input module
Digital input SM 421 for the SIMATIC S7-400 series.
Digital input SM 421 for the SIMATIC S7-400 series.
16 isolated digital inputs
Provides 16 DI with potential separation between the channels and between the channels and backplane bus.
Provides 16 DI with potential separation between the channels and between the channels and backplane bus.
UC 120/230 V inputs
Rated value (UC): 230 V; 120/230 V UC (47 … 63 Hz).
Rated value (UC): 230 V; 120/230 V UC (47 … 63 Hz).
AC/DC input voltage
Type of input voltage: AC/DC, with input characteristic according to IEC 61131 Type 2.
Type of input voltage: AC/DC, with input characteristic according to IEC 61131 Type 2.
2-wire sensor support
Connectable encoders include 2-wire sensor: Yes.
Connectable encoders include 2-wire sensor: Yes.
Applications
Digital signal acquisition
Monitoring 16 AC/DC input signals through isolated digital input channels.
Monitoring 16 AC/DC input signals through isolated digital input channels.
2-wire sensor connection
Connecting 2-wire sensors to the digital input channels.
Connecting 2-wire sensors to the digital input channels.
Frequently Asked Questions
What is 6ES7421-1FH20-0AA0 in the SIMATIC S7-400 series?
It is a SIMATIC S7-400 digital input SM 421 module with 16 isolated DI.
How many digital inputs does 6ES7421-1FH20-0AA0 have?
It has 16 digital inputs.
What input voltage does 6ES7421-1FH20-0AA0 support?
The module uses AC/DC input voltage and is specified for UC 120/230 V inputs.
Does 6ES7421-1FH20-0AA0 support 2-wire sensors?
Yes. Connectable encoders include 2-wire sensor: Yes.
What cable lengths are specified for 6ES7421-1FH20-0AA0?
The maximum cable length is 1 000 m for shielded cable and 600 m for unshielded cable.
