Siemens S7-1200 G1 vs G2 Upgrade Guide for 2026
Learn the key differences between Siemens S7-1200 G1 and G2 PLCs, including lifecycle status, performance, memory, motion control, PROFINET, cybersecurity and hardware compatibility. Discover which S7-1200 G2 CPU fits your machine and how to plan a G1-to-G2 migration with TIA Portal while minimizing engineering and downtime risks.
Key Takeaways
- Siemens plans to begin phasing out the S7-1200 G1 on November 1, 2026; new-device ordering is planned through October 31, 2027, with spare-part availability planned to approximately 2036.
- G2 delivers substantially higher computing capability, more memory, modern motion functions and PROFINET isochronous communication.
- G1 hardware is not directly hardware-compatible with G2, so migration requires an engineering and hardware compatibility review.
- Siemens provides an S7-1200 G2 Migration Tool for TIA Portal-based project migration, but engineering validation remains essential.
Why the S7-1200 G1 vs G2 Decision Matters in 2026
The S7-1200 G1 remains a capable compact PLC for many existing machines. However, Siemens has announced a gradual phase-out beginning November 1, 2026. Siemens states that G1 controllers can still be ordered as new devices through October 31, 2027, while spare-part availability is planned to continue to approximately 2036. This means the transition is a lifecycle-management issue, not an overnight obsolescence event.
For new designs, the S7-1200 G2 is the logical platform. For installed G1 systems, the correct question is not simply “Is G2 newer?” but “Does migration reduce technical or commercial risk enough to justify the engineering and downtime cost?”
See Siemens' official automation migration guidance for current lifecycle information.
S7-1200 G1 vs G2: Key Differences
Performance, memory and scan cycle
G2 was designed as a higher-performance successor, with increased computing capacity and larger memory reserves. For engineers, the practical benefit is greater headroom for program execution, data handling, diagnostics and future functions. Actual scan-cycle improvement depends on program structure, I/O configuration and communication load, so a fixed percentage improvement should not be assumed for every application.
PROFINET and communication
Both generations are centered on PROFINET, but G2 expands the platform's capabilities for modern networked automation. G2 supports isochronous PROFINET operation, making deterministic communication relevant to applications requiring tighter coordination between controllers, drives and field devices.
Motion control and PROFINET IRT
Motion is one of the clearest architectural differences. G2 provides integrated Motion Control capabilities, including axis control and synchronization functions, with deterministic communication to suitable drive technology through PROFINET IRT. This makes G2 more attractive for handling, packaging and machine applications where coordinated motion is part of the control strategy.
Safety and cybersecurity
G2 introduces a modern safety and cybersecurity portfolio. Siemens states that the G2 platform is certified according to IEC 62443 and designed for current industrial cybersecurity requirements. This does not make a machine automatically “secure” or compliant with every regulatory obligation: risk assessment, network architecture, access control, patch management and application-specific safety engineering remain necessary.
Engineering and TIA Portal
G2 remains integrated into the Siemens TIA Portal engineering environment. Siemens also provides a dedicated S7-1200 G2 Migration Guideline and Migration Tool to help convert existing projects.
S7-1200 G1 vs G2 Comparison
| Area | S7-1200 G1 | S7-1200 G2 |
|---|---|---|
| Lifecycle | Established platform entering phase-out | Current-generation platform |
| Performance | Suitable for established compact machines | Higher processing and memory headroom |
| Motion | More limited motion architecture | Integrated, expanded Motion Control capabilities |
| PROFINET | Core industrial Ethernet capability | Enhanced communication and isochronous operation |
| Hardware compatibility | Original S7-1200 hardware ecosystem | New hardware architecture; G1 modules are not directly interchangeable |
| Best fit | Existing, stable installations | New machines and planned modernization |
Price should be evaluated as total cost of ownership (TCO), not CPU purchase price alone. A G1 controller may be cheaper to retain, while G2 can reduce future engineering effort, improve performance headroom and simplify long-term platform planning.
Which S7-1200 G2 CPU Should You Choose?
CPU 1212C: Compact machines
The CPU 1212C is a sensible starting point for smaller machines with modest I/O and program requirements. Current G2 variants provide 150 KB program memory and 500 KB data memory, with integrated digital I/O depending on the selected power/output configuration.
CPU 1214C: The balanced choice
The CPU 1214C is generally the strongest default for machine builders who want meaningful I/O and memory headroom without moving unnecessarily high in the range. The DC/DC/DC version provides 14 digital inputs, 10 digital outputs, 250 KB program memory and 750 KB data memory.
CPU 1215C: Higher application demands
Choose the CPU 1215C when the application requires more processing, I/O or integrated analog capability than the smaller compact CPUs provide. Selection should be based on the complete hardware configuration and current Siemens specifications rather than CPU numbering alone.
For current product specifications, consult the Siemens S7-1200 G2 product page before finalizing a bill of materials.
Should You Upgrade an Existing S7-1200 G1?
Upgrade now when the machine needs higher performance, integrated modern motion control, improved cybersecurity capabilities, additional memory or a longer-term controller platform. Planned upgrades are also easier to justify when a machine is already scheduled for electrical or mechanical refurbishment.
Keep G1 when the machine is stable, spare parts are available, the program has adequate scan-cycle margin, cybersecurity requirements are satisfied by the existing architecture, and there is no near-term functional expansion.
Do not treat the November 2026 phase-out date as a forced shutdown date. Instead, use it as a trigger to review installed-base risk, critical spare inventory, supplier lead times and future machine modifications.
How to Migrate from S7-1200 G1 to G2
- Audit the existing PLC: document CPU, firmware, signal modules, communication modules, HMI, drives, technology objects and third-party devices.
- Map the hardware: identify G2 equivalents and check every I/O and communication component. G1 and G2 hardware are not directly interchangeable.
- Check engineering compatibility: verify TIA Portal, firmware and device-catalog requirements before opening the migration project.
- Run the Migration Checker: Siemens' tool identifies hardware and software compatibility issues before migration.
- Reconfigure manually where required: HMI connections, hardware properties, certain motion technology objects, safety elements and unsupported modules may require additional engineering.
- Test offline and on a controlled test system: validate I/O behavior, communication, alarms, motion, safety and recovery behavior before production cutover.
Migration pitfall: “The program migrated successfully” does not mean “the machine is validated.” Siemens documentation identifies several items that are not automatically transferred, including HMI connections, traces, certain motion technology objects and hardware properties. Treat the migration as an engineering project, not a file-conversion exercise.
Practical Upgrade Scenario: Packaging Machine
Consider a packaging machine using a G1 CPU, distributed PROFINET I/O, an HMI and several coordinated drive functions. A sensible upgrade sequence is to freeze the current project, inventory all devices, run the Migration Checker, select the G2 CPU based on actual I/O and motion requirements, migrate the software, rebuild unsupported hardware properties and validate the complete sequence on a test setup.
The highest-risk areas are typically device configuration, drive telegrams, HMI communication, motion technology objects and timing-dependent logic. Keeping a complete G1 backup and commissioning procedure provides a practical rollback path.
S7-1200 G2 vs Other Compact PLC Platforms
Omron NX/NJ: a strong choice when an installation is already standardized on Omron Sysmac and advanced motion integration is central to the machine.
Schneider Modicon M241/M262: attractive where EcoStruxure Machine Expert and Schneider Electric's broader automation ecosystem are already established.
Mitsubishi FX5U: well suited to compact machines where Mitsubishi's MELSEC ecosystem, high-speed control and existing engineering expertise are priorities.
The S7-1200 G2 makes the most sense when Siemens engineering standards, TIA Portal, PROFINET and the wider Siemens automation ecosystem are already part of the plant or OEM design standard.
Recommended Siemens S7-1200 G2 Models
| Model | Recommended use | Selection rationale |
|---|---|---|
| CPU 1212C | Compact machines | Best where I/O and program requirements are modest. |
| CPU 1214C | General machine automation | Balanced I/O, memory and expansion capability. |
| CPU 1215C | More demanding compact applications | Choose when application, I/O, analog or performance requirements exceed the smaller CPUs. |
Conclusion
The S7-1200 G2 is the preferred choice for new machine designs in 2026 because it provides a current platform with greater performance headroom, expanded motion capabilities, modern cybersecurity features and a defined migration path.
Existing G1 installations do not need to be replaced simply because 2026 arrives. If the machine remains reliable and technically adequate, continued operation can be reasonable. The smarter strategy is to build a migration plan before a failure, expansion project or component shortage forces an unplanned decision.
When you're ready to evaluate controller options, I/O or replacement hardware, explore Siemens PLC products at Chipsgate.
FAQ
Can I keep using my S7-1200 G1 after 2026?
Yes. The 2026 date marks the beginning of Siemens' planned phase-out, not an automatic end of operation for installed G1 controllers. Siemens plans spare-part availability for G1 modules to approximately 2036, subject to the stated lifecycle conditions.
Do I need to replace my S7-1200 G1 immediately?
No. Replacement should be driven by application requirements, lifecycle risk, spare strategy, cybersecurity needs, performance margin and planned machine modifications.
Is S7-1200 G2 faster than G1?
Yes. Siemens describes G2 as having significantly increased computing power and larger memory reserves. However, actual scan-cycle improvement varies with the application and should be measured rather than assumed.
Can I directly replace a G1 CPU with a G2 CPU?
No. G2 uses a new hardware architecture and is not hardware-compatible with the previous S7-1200 family. Existing programs can generally be converted, but hardware, firmware, I/O, HMI and communication compatibility must be checked.
Is S7-1200 G2 better for motion control?
Yes. Motion Control is a major G2 enhancement. Its integrated capabilities and PROFINET IRT support make it better suited to coordinated motion applications than the original S7-1200 architecture.