SM 1222 is the Siemens SIMATIC S7-1200 digital output signal-module family. It expands an S7-1200 station with transistor or relay outputs, but the family name alone does not identify one electrical configuration or ordering number.

The 6ES7222 order number must be selected from the required channel count and output technology. Available S7-1200 variants include 8- or 16-channel 24 V DC transistor outputs, 8- or 16-channel relay outputs and an 8-channel relay changeover version.

Manufacturer	Siemens
Product Family	SIMATIC S7-1200
Family Designation	SM 1222
Product Type	Digital output signal module family
Order Number Format	Variant-specific 6ES7222 MLFB required
8-Channel Transistor Variant	6ES7222-1BF32-0XB0, 8 outputs, 24 V DC, 0.5 A
16-Channel Transistor Variant	6ES7222-1BH32-0XB0, 16 outputs, 24 V DC, 0.5 A
Sinking Transistor Variant	6ES7222-1BH32-1XB0, 16 outputs, 24 V DC, 0.5 A
8-Channel Relay Variant	6ES7222-1HF32-0XB0, 8 relay outputs, 2 A
16-Channel Relay Variant	6ES7222-1HH32-0XB0, 16 relay outputs, 2 A
Relay Changeover Variant	6ES7222-1XF32-0XB0, 8 relay changeover outputs
Installation Context	S7-1200 signal-module position
Engineering Context	Configured by the exact MLFB in the S7-1200 project

• Adds digital output capacity to a SIMATIC S7-1200 controller station.
• Offers transistor versions for fast 24 V DC load switching.
• Offers relay versions for galvanically switched AC or DC load circuits within the selected module ratings.
• Provides 8- and 16-channel configurations for different machine I/O densities.
• Includes an 8-output relay changeover variant for applications requiring changeover contacts.
• Uses model-specific diagnostics, terminal assignment and current limits defined by the complete 6ES7222 order number.

• S7-1200 machine controllers requiring additional 24 V DC transistor outputs.
• Automation panels that need relay switching for isolated field loads.
• Compact I/O expansion with eight output channels.
• Higher-density stations requiring sixteen digital outputs.
• Maintenance of an installed S7-1200 station after the full 6ES7222 MLFB is confirmed.

• Treat SM 1222 as a family designation until the complete 6ES7222 order number is read from the module label or project.
• Do not transfer current, voltage, grouping or diagnostic data from one SM 1222 variant to another.
• Record the full MLFB, channel count, transistor or relay technology, terminal wiring and STEP 7 configuration before replacement.
• When moving between module generations, verify CPU compatibility, hardware-catalog support and terminal assignment.
• Commission every output channel and connected load after installing the exact replacement variant.

Is SM 1222 a complete Siemens ordering number?

No. It is a product-family designation; the exact module requires a complete 6ES7222 order number.

Are all SM 1222 modules transistor-output devices?

No. The family includes transistor, relay and relay-changeover versions.

Which channel counts are available in the S7-1200 family?

The documented family includes 8- and 16-output configurations, depending on the selected MLFB.

Can a relay model directly replace a transistor model?

No. The output technology, load ratings, wiring, response and project hardware entry must all be reviewed.

What information is needed to identify an installed module?

Read the complete 6ES7222 MLFB and record the channel count, output type, terminal wiring and project configuration.

Why is a single weight not shown for SM 1222?

Weight and dimensions belong to the selected catalog variant; the family name alone does not identify one exact hardware article.