Siemens 6ES7221-1BF32-0XB0 SM 1221 8-Point Digital Input Module
An eight-point S7-1200 digital input expansion module identified by the complete Siemens MLFB.
Key Information
6ES7221-1BF32-0XB0 is the SIMATIC S7-1200 SM 1221 module for eight 24 V DC digital inputs. Siemens identifies the input behavior as sink/source, allowing the module to be documented against the field switching arrangement used by the machine.
The 8-point execution must be kept separate from the visually related 16-point SM 1221. The complete MLFB, terminal assignment and CPU hardware record form the selection boundary.
Siemens lists a 0.150 kg net weight and an 8.80 × 10.90 × 6.00 cm package for this exact article.
Functions
Field-state acquisition
Receives eight discrete 24 V DC states and transfers their process image to the S7-1200 controller.
Sink/source wiring context
Supports the published sink/source input arrangement; field polarity and common routing remain installation-specific.
Channel-level commissioning
Allows each wired point to be proved against the PLC tag list during controlled startup.
Compact expansion role
Adds a limited eight-point input block where the project does not require the wider 16-point execution.
Specifications
| Manufacturer | Siemens | Exact model | 6ES7221-1BF32-0XB0 |
|---|---|---|---|
| Product family | SIMATIC S7-1200 | Module designation | SM 1221 |
| I/O direction | Digital input | Number of inputs | 8 |
| Rated input voltage | 24 V DC | Input characteristic | Sink/source |
About IndustryParts
https://www.industryparts.com/Exact-model handling for 6ES7221-1BF32-0XB0
IndustryParts keeps the complete model label, requested quantity, application evidence and delivery requirements together so the proposed supply can be checked against the installed system before dispatch.
Installation
Document the eight-point map
Export the PLC project and mark every physical terminal against its tag, common and field device.
Confirm the electrical scheme
Check 24 V DC distribution, sink/source convention, conductor condition and protective devices before fitting.
Prove one channel at a time
After restoration, exercise each input and verify the expected CPU state without disturbing unaffected logic.
Lifecycle
Procurement
Retain the full 6ES7221-1BF32-0XB0 MLFB; do not shorten the request to SM 1221 or substitute the 16-input version.
Storage
Protect the connector area and keep the manufacturer label legible for future audit.
Service evidence
Archive the project checksum, terminal photographs and completed eight-point functional test.
Related Models
FAQ
What evidence should accompany a 6ES7221-1BF32-0XB0 enquiry?
Send the CPU MLFB, full module label, terminal photographs, eight-point I/O map, project version and required quantity.
Can 6ES7221-1BF32-0XB0 be replaced by 6ES7221-1BH32-0XB0 without review?
No. The related module has sixteen inputs; connector allocation, project addressing and panel space must be reassessed.
How should sink/source wiring be confirmed for 6ES7221-1BF32-0XB0?
Use the approved circuit drawing and actual common polarity, then compare every terminal with the Siemens wiring information.
What should be recorded before removing 6ES7221-1BF32-0XB0?
Record the installed slot, firmware and project baseline, conductor markers, input commons and live-state observations.
What proves 6ES7221-1BF32-0XB0 is ready after service?
Confirm all eight physical inputs change the intended PLC tags and that diagnostics and machine interlocks return to their approved state.
