S7-1200 G1 Phase-Out 2026: Migration to S7-1200 G2 Reference

Overview of the S7-1200 G1 Phase-Out

The SIMATIC S7-1200 first-generation (G1) controller family has been formally declared for phase-out by Siemens. According to the official advance notice of product discontinuation published on the Siemens Industry Online Support portal under document ID 109996314, the SIMATIC S7-1200 (G1) family is scheduled to enter the official product phase-out (PM400) milestone on November 1, 2026, with product cancellation (PM410) following on October 1, 2027. The successor platform, marketed as the S7-1200 G2, is the designated replacement.

For systems integrators, plant engineers, and panel builders, these two dates define the boundary of a roughly two-year runway in which to design out G1 hardware from new projects, qualify the G2 platform against existing firmware, qualify G2 spare-parts inventory, and complete migration of long-life-cycle assets (HVAC, water/wastewater, building automation, packaging lines) where the controller may remain in service for 15-20 years. The phase-out applies to the entire G1 family - CPU models 1211C, 1212C, 1214C, 1215C, 1217C, the associated signal boards (SB), signal modules (SM), communication modules (CM), battery boards (BB), and the 4PM/2PM power-supply variants - although the specific cancellation list of catalog numbers must be confirmed against the official product discontinuation entry prior to any stock or design decision.

Siemens Lifecycle Milestone Definitions

Siemens uses standardized product-lifecycle codes on every data sheet and product-discontinuation notice. Two milestones are relevant to the S7-1200 G1 transition:

Note that the PM490 date is published per article number on the official product discontinuation pages and is not a single calendar date for the entire family. Field engineers should retrieve the article-number-specific entry from the Siemens Industry Online Support portal before issuing final-phase spare-parts purchase orders.

Affected G1 Catalog Range (Scope of Phase-Out)

The S7-1200 G1 family covers a wide range of catalog numbers. While the official discontinuation document (ID 109996314) contains the binding list, the typical scope includes:

• CPU 1211C DC/DC/DC, DC/DC/Relay, AC/DC/Relay (6ES7211-1xxx)
• CPU 1212C DC/DC/DC, DC/DC/Relay, AC/DC/Relay (6ES7212-1xxx)
• CPU 1214C DC/DC/DC, DC/DC/Relay, AC/DC/Relay (6ES7214-1xxx)
• CPU 1215C DC/DC/DC, DC/DC/Relay, AC/DC/Relay (6ES7215-1xxx)
• CPU 1217C DC/DC/DC (6ES7217-1xxx)
• Signal Modules SM 12xx (digital and analog in/out)
• Signal Boards SB 12xx (digital and analog in/out, limited to 1 slot on G1)
• Communication Modules CM 1241 (RS232, RS485) and CP 1242/1243/1244
• Battery Board BB 1297
• PM 1207 power supplies (6EP1332-1xxx)

Note: A prior phase-out campaign already retired the S7-1200 V3.0 hardware tier; the current PM400/PM410 schedule targets the V4.x firmware / hardware generation of G1.

S7-1200 G1 vs G2 - Hardware Comparison

The G2 platform is a re-architecture rather than a refresh. Engineers migrating G1 designs must plan for changes at every level: CPU processing, memory, I/O density, signal board count, OPC UA, and the engineering toolchain.

All numeric values for the G2 column must be verified against the current G2 system manual "Comparison to S7-1200" chapter, which Siemens publishes as the authoritative cross-reference.

Mechanical and Form-Factor Differences

The S7-1200 G2 is larger than the G1 in both height and depth, even before connectors are plugged in. This has direct consequences for cabinet layout retrofits and for compact installations that selected the G1 specifically for its low profile.

Migration paths for height-constrained installations include: (1) using the LOGO! platform (with Ethernet) for low I/O-count applications where S7-1200 functionality is not required; (2) enlarging the enclosure or relocating to a 4U footprint; (3) maintaining G1 stock for the duration of the asset's life cycle and planning a forward replacement at the next major overhaul.

Software Migration - TIA Portal V20 and V21

The S7-1200 G1 final firmware maintenance is performed inside TIA Portal V20. New G2 projects are first-class citizens of TIA Portal V20, but several G2 capabilities - notably the native OPC UA server, the NFC service-interface companion application, and the expanded trace/trace-with-project-tracing features - require TIA Portal V21. V21 is scheduled to release in the late-2025 / early-2026 window, which aligns with the practical G2 commissioning window after PM400.

Project Portability Rules

1. A TIA Portal project that targets an S7-1200 G1 CPU cannot be loaded into a G2 CPU without a device change in the project tree. Engineers should expect to use the "Change device" / "Migrate device" function and to manually re-resolve library elements, hardware catalog versions, and any G1-specific option-handling code.
2. Firmware function blocks (FB) that were written for G1 firmware V4.x are source-compatible with G2 in most cases, but the G2 compiler may flag deprecated or renamed instructions. A test pass on the G2 simulator is mandatory before commissioning.
3. Recipe data, Data Logs, and the retentive memory layout are not portable directly. The migration must remap DB structures to G2 memory boundaries.
4. Web-server user-defined pages authored in V17 or earlier must be re-validated against the G2 web server's HTTPS / certificate model.

New G2 Capabilities Relevant to the Migration Decision

NFC Service Interface

The G2 introduces a near-field communication (NFC) service interface on the CPU front. Diagnostic and identification data can be read from the CPU by tapping an iPhone (with the Siemens companion app installed) against the controller. This is intended for commissioning, asset tagging, and rapid identification of the controller on the plant floor. The companion application is delivered for iOS; Android availability is not announced at the time of writing.

OPC UA Server

The G2 OPC UA server, when enabled in TIA Portal V21, exposes a configurable address space of tags, methods, and alarms. This is a step change from the G1's optional/limited OPC UA, and positions the G2 as a viable edge-of-network data concentrator. Engineers should plan IT-side certificates, security policies, and firewall rules accordingly.

Dual Signal Board Slots

The G2 CPU supports two signal boards. This is a significant I/O-density win for compact machines: a single G2 CPU can replace a G1 CPU + one expansion module in some low-channel-count applications. The signal board catalog is split between legacy G1-compatible SBs (forward-compatible) and new G2-only SBs that add functions not available on G1 (additional high-speed counters, additional analog resolution, etc.).

Web Server and Security

The G2 web server supports HTTPS with user-managed certificates. G1 web servers in default configuration run on plain HTTP, which is a frequent audit finding in brownfield sites. A G2 migration is an opportunity to close this gap.

Spare-Parts and Lifecycle Strategy

The two-year window between PM400 (2026-11-01) and PM410 (2027-10-01) is the practical procurement window. Engineering teams should treat the cancellation date as a hard deadline for any new orders against G1 catalog numbers, and PM490 (end of service) as the final date beyond which a failed G1 module cannot be returned to Siemens for repair.

Recommended Spare-Parts Planning

1. Inventory the G1 catalog numbers in use across the active fleet. Generate a bill of material from the TIA Portal project archive (not from a manual spreadsheet) so that firmware version, hardware version, and MLFB are unambiguous.
2. For each asset, classify the controller by criticality: (a) production-critical, no redundancy; (b) production-critical with redundant PLC; (c) non-critical utility. Category (a) requires stocking at least one full CPU plus the I/O modules in the same cabinet. Category (b) can rely on the in-cabinet spare. Category (c) typically carries a shared spare at a regional depot.
3. Issue a final stock purchase ahead of the PM410 date (2027-10-01). Note that orders placed after PM400 are subject to "last-time-buy" pricing and are non-cancellable / non-returnable; the quantity is a long-term commitment.
4. For assets with a remaining service life of 10+ years, plan a forward migration to G2 at the next planned shutdown. Do not assume G1 stock from a third-party broker will be available at any reasonable price after PM490.

Migration Decision Matrix

The matrix below is a practical decision aid for selecting between (1) maintaining the G1 with a final-time-buy spare-parts stock, (2) forward-migrating to G2, or (3) substituting a different platform such as LOGO! or S7-1500.

Field-Proven Engineering Notes

• Confirm the exact list of article numbers in the official discontinuation notice. Siemens may continue to produce long-life-cycle variants (e.g. SIPLUS extreme, specific regional SKU) on a separate schedule.
• The G2 is rolling out in waves. At the time of the official phase-out announcement, several G2 modules (notably high-density SMs, certain communication modules) were not yet generally available. Do not plan a project that requires a module that is not yet orderable as a standard catalog item.
• Existing G1 documentation that mentions "S7-1200 G2 compatible" should be treated with caution. Where the source predates the G2 release, check the current G2 system manual and the official product announcement page for confirmed compatibility.
• For customers who rely on the LOGO! 8 platform for low I/O-count applications, the LOGO! CMR (4G router) and LOGO! 8.4 generation remain a stable forward path and are not affected by the S7-1200 G1 phase-out.
• Order processing for PM400 SKUs is not uniform. Some are flagged with immediate effect, others are extended on a regional basis. Confirm with the local Siemens sales organization before issuing blanket purchase orders.

Verification Steps Before Committing to Migration

1. Open the TIA Portal project for the asset, identify the G1 CPU's exact MLFB and firmware version, and export the hardware configuration as a TIA Portal exchange file.
2. Open the project in TIA Portal V20 (latest update) and perform a "Change device" to the equivalent G2 CPU. Document every warning, every unsupported instruction, and every hardware module that does not have a direct G2 successor.
3. Run the PLCSIM simulation against the migrated G2 program and confirm that all I/O, motion, and communication paths behave identically to the G1 baseline.
4. Mock up a sample G2 module in the target cabinet. Confirm the height, depth, and connector clearance against the enclosure's internal dimensions before cutting cable ducts or finalizing the layout drawing.
5. Validate cybersecurity posture: HTTPS certificates, user management, OPC UA security policies, and any open port inventory against the plant's network policy.
6. Update the asset register, the spare-parts inventory, and the maintenance procedures to reflect the G2 catalog numbers and the G2 firmware update path.

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