Programmable Logic Controller Guide: Selection, Application, and Maintenance for Engineers
PLC selection guide for engineers covering IEC 61131 compliance, Siemens, Rockwell, Schneider, ABB comparison, scan time sizing, and wiring. Shop at Stoklink.
- Part number
- 6ES7221-1BH50-0XB0
- Model no
- SM 1221, DI 16x 24 V DC
In stock · 50+
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· From Türkiye
0
- CE
SIMATIC S7-1200Siemens 6ES7221-1BH50-0XB0 SIMATIC S7-1200 SM 1221 16DI 24V DC PLC I/O Module
Siemens SM 1221 16 DI 24V DC digital input module for SIMATIC S7-1200, IP20, cULus certified.
Description
About the SM 1221, DI 16x 24 V DC
About the SM 1221, DI 16x 24 V DC
The Siemens 6ES7221-1BH50-0XB0 SM 1221 is a digital input module for the SIMATIC S7-1200 that adds 16 DC digital inputs rated 24 V DC, wired in groups of four. Input delay is parameterizable from 0.2 ms to 12.8 ms per group. The module draws its logic power from the backplane bus, drawing 90 mA max, and carries IP20 protection.
Certifications & Standards
- CE
- UL
- cULus
- RCM
- KC
Selection Notes
16 DI in groups of four covers larger field-input counts than the CPU's onboard channels without adding a second module - each group of four shares one input-delay setting, so wire similar sensor types (dry contacts vs. proximity switches) together within a group to keep the delay setting appropriate for all of them. Sink/source wiring on every channel means the module accepts both PNP and NPN field devices without rewiring. Choose this 16 DI module over an 8 DI variant when expansion-slot count is limited and the full 16 channels are needed in one card.
Applications
Expands digital input capacity on SIMATIC S7-1200 stations for pushbuttons, limit switches, proximity sensors, and other 24 V DC dry-contact or transistor-output field devices where onboard CPU inputs are insufficient.
Specification
Full specification
General information 1
| Product type designation | SM 1221, DI 16x 24 V DC |
|---|
Input current 2
| from backplane bus 5 V DC, max. | 90 mA |
|---|---|
| Digital inputs: from load voltage L+ (without load), max. | 4.1 mA; per channel |
Power loss 1
| Power loss, typ. | 3.2 W |
|---|
Show all 81 specifications ↓ Show less ↑77 more values in Identification, Digital inputs, Interrupts/diagnostics/status information, Potential separation, Isolation, Degree and class of protection, Standards, approvals, certificates, Ambient conditions, Connection method, Mechanics/material, Dimensions, Weights, Approvals / Certificates, General Product Approval EMV, For use in hazardous locations Test Certificates, Logistics.
Identification 10
| Part number | 6ES7221-1BH50-0XB0 |
|---|---|
| Type designation | SM 1221, DI 16x 24 V DC |
| Brand | Siemens |
| Condition | New, factory sealed |
| Source | Siemens and its authorised distributors |
| Warranty | Manufacturer warranty |
| Lifecycle status | Active, in production |
| EAN | 4047623417286 |
| ETIM class | EC001419 |
| eCl@ss | 27242204 |
Digital inputs 13
| Number of digital inputs | 16 |
|---|---|
| in groups of | 4 |
| Input characteristic curve in accordance with IEC 61131, type 1 | Yes |
| Number of simultaneously controllable inputs horizontal installation: up to 40 °C, max. | 16 |
| Input voltage: Rated value (DC) | 24 V |
| Input voltage: for signal "0" | 5 V DC or 0.5 mA |
| Input voltage: for signal "1" | 15 V DC at 2.5 mA |
| Input current: for signal "0", max. (permissible quiescent current) | 0.5 mA |
| Input current: for signal "1", min. | 2.5 mA |
| Input current: for signal "1", typ. | 4.1 mA |
| Input delay (for rated value of input voltage) for standard inputs: parameterizable for interrupt inputs | Yes; 0.2 ms, 0.4 ms, 0.8 ms, 1.6 ms, 3.2 ms, 6.4 ms and 12.8 ms, selectable in groups of four |
| Cable length: shielded, max. | 500 m |
| Cable length: unshielded, max. | 300 m |
Interrupts/diagnostics/status information 5
| Diagnostics function | Yes |
|---|---|
| Alarms: Diagnostic alarm | No |
| Diagnoses: Monitoring the supply voltage | No |
| Diagnostics indication LED: for status of the inputs | Yes |
| Diagnostics indication LED: for maintenance | Yes |
Potential separation 2
| Potential separation digital inputs: between the channels, in groups of | 4 |
|---|---|
| Potential separation digital inputs: between the channels and backplane bus | Yes; 707 V DC (type test) |
Isolation 1
| Isolation tested with | 707 V DC (type test) |
|---|
Degree and class of protection 1
| IP degree of protection | IP20 |
|---|
Standards, approvals, certificates 14
| Siemens Eco Profile (SEP) | Siemens EcoTech |
|---|---|
| CE mark | Yes |
| CSA approval | No |
| UL approval | Yes |
| cULus | Yes |
| FM approval | No |
| RCM (formerly C-TICK) | Yes |
| KC approval | Yes |
| Marine approval | No |
| Ecological footprint: environmental product declaration Global warming potential | Yes; type 2 acc. to ISO 14021 |
| Ecological footprint: global warming potential, (total) [CO2 eq] | 40.3 kg |
| Ecological footprint: global warming potential, (during production) [CO2 eq] | 7.79 kg |
| Ecological footprint: global warming potential, (during operation) [CO2 eq] | 32.5 kg |
| Ecological footprint: global warming potential, (after end of life cycle) [CO2 eq] | -0.089 kg |
Ambient conditions 15
| Free fall: Fall height, max. | 0.3 m; five times, in product package |
|---|---|
| Ambient temperature during operation: horizontal installation, min. | -20 °C |
| Ambient temperature during operation: vertical installation, min. | -20 °C |
| Ambient temperature during storage/transportation: min. | -40 °C |
| Ambient temperature during storage/transportation: max. | 70 °C |
| Air pressure acc. to IEC 60068-2-13: Operation, min. | 540 hPa |
| Air pressure acc. to IEC 60068-2-13: Operation, max. | 1 140 hPa |
| Air pressure acc. to IEC 60068-2-13: Storage/transport, min. | 540 hPa |
| Air pressure acc. to IEC 60068-2-13: Storage/transport, max. | 1 140 hPa |
| Altitude during operation relating to sea level: Installation altitude, min. | -1 000 m |
| Relative humidity: Operation at 25 ℃ without condensation, max. | 95 % |
| Vibrations: Vibration resistance during operation acc. to IEC 60068-2-6 | 3.5 mm from 5 - 8.4 Hz, 1g from 8.4 - 150 Hz |
| Vibrations: Operation, tested according to IEC 60068-2-6 | Yes |
| Shock testing: tested according to IEC 60068-2-27 | Yes; IEC 68, Part 2-27 half-sine: strength of the shock 15 g (peak value), duration 11 ms |
| Pollutant concentrations: SO2 at RH < 60% without condensation | S02: < 0.5 ppm; H2S: < 0.1 ppm; RH < 60 % condensation-free |
Connection method 1
| required front connector | No |
|---|
Mechanics/material 1
| Enclosure material (front): Plastic | Yes |
|---|
Dimensions 3
| Width | 30 mm |
|---|---|
| Height | 125 mm |
| Depth | 100 mm |
Weights 1
| Weight, approx. | 166 g |
|---|
Approvals / Certificates 1
| General Product Approval | Miscellaneous |
|---|
General Product Approval EMV 1
| Manufacturer Declara- China RoHS | tion |
|---|
For use in hazardous locations Test Certificates 1
| Miscellaneous CCC-Ex CCC-Ex Type Test Certific- | ates/Test Report |
|---|
Logistics 7
| Net weight | 0.166 kg |
|---|---|
| Package dimensions | 150 × 47 × 110 mm |
| Country of origin | CN |
| Shipping weight | 0.666 kg |
| Ships from | Türkiye |
| Dispatch | 13 Nov |
| Stock | In stock |
Source: manufacturer data · Last verified: 01 Nov 2026
Documents
Documents for 6ES7221-1BH50-0XB0
No documents are on file for this part yet.
Ask us for the datasheet
Certifications
Certifications and standards
- CE
- CE mark
- UL approval
- cULus
- RCM (formerly C-TICK)
- KC approval
Quick answers
Questions about the SM 1221, DI 16x 24 V DC
Which supply voltage is SM 1221, DI 16x 24 V DC rated for?
The rated operational voltage of SM 1221, DI 16x 24 V DC is 24 V AC.
What is the HS code of SM 1221, DI 16x 24 V DC for customs?
The tariff (HS) code on file for SM 1221, DI 16x 24 V DC is 85389091.
What is the EAN of SM 1221, DI 16x 24 V DC?
The EAN (GTIN) of SM 1221, DI 16x 24 V DC is 4047623417286.
Where does SM 1221, DI 16x 24 V DC ship from, and how fast?
SM 1221, DI 16x 24 V DC ships from Türkiye. Shipping calculated at checkout · import duties and taxes paid on arrival. Stock items are dispatched within 1–2 business days.
Guides
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Reviews
Customer reviews
Series
Siemens SIMATIC S7-1200
- Brand
- Siemens
- Series
- SIMATIC S7-1200
