Isolated 32-channel digital input module for acquiring 24 V DC field signals in S7-400 systems.
Complete order number
6ES7421-1BL01-0AA0
Siemens 6ES7421-1BL01-0AA0 is a SIMATIC S7-400 SM 421 digital input module with 32 isolated 24 V DC inputs. Siemens specifies all 32 inputs as simultaneously controllable.
The module reads standard Type 1 digital input signals and provides green channel status indication. Replacement planning should confirm the S7-400 rack configuration, 24 V DC field circuits, front connector and engineering assignment.
| Manufacturer | Siemens |
| Complete part number | 6ES7421-1BL01-0AA0 |
| Product family | SIMATIC S7-400 |
| Official designation | SM 421 digital input module |
| Input configuration | 32 DI; 24 V DC |
| Lifecycle wording | PM300: Active Product; product phase-out since 2025-10-01 |
| Backplane current at 5 V DC | 20 mA maximum |
| Power loss, typical | 6 W |
| Number of digital inputs | 32 |
| Rated input voltage | 24 V DC |
| Signal 0 voltage range | -30 V DC to +5 V DC |
| Signal 1 voltage range | 13 V DC to 30 V DC |
| Input current for signal 1 | 7 mA typical |
Collects multiple 24 V DC on/off signals from field switches and sensors.
Provides dense 32-channel input capacity for status, permissive and interlock signals.
Supports exact-module replacement in installed S7-400 automation racks.
It is a Siemens SIMATIC S7-400 SM 421 digital input module.
The module provides 32 digital inputs rated for 24 V DC.
Yes. Siemens specifies potential separation between the input group and the backplane bus.
Siemens lists no diagnostic function, but green status indication is provided for the digital inputs.
Provide the module label, rack and CPU references, front-connector details, quantity and destination.
Send the installed module label and S7-400 rack configuration for identification, availability and compatibility review.
Email: sales6@apterpower.com WhatsApp: +86 18159889985
Identification, channel-configuration review and procurement support for SIMATIC S7-400 signal modules.
We compare the complete SM 421 suffix, 32-input configuration and 24 V DC rating before quotation.
Rack assignment, front connector, field wiring, input thresholds and channel status are reviewed.
Availability, inspection options, warranty scope, packing and global delivery are confirmed with the offer.
Provide 6ES7421-1BL01-0AA0, clear label photos, rack and CPU references, front connector, quantity and destination.
Confirm 32 DI at 24 V DC and the exact S7-400 slot configuration. Similar SM 421 variants may have different channel or voltage ratings.
Contact us for exact identification, condition requirements, compatibility checks, warranty information and worldwide shipping.
Email: sales6@apterpower.com WhatsApp: +86 18159889985
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Send the complete model number and quantity for supply verification, compatibility checks, warranty details and worldwide delivery.
Email: sales6@apterpower.com WhatsApp: +86 18159889985
