Feasibility of PCS 7 Project and APL Downgrade from V9.0 SP2 to V9.0 SP1 and License Compatibility

In SIMATIC PCS 7, downgrading an engineering project, CFC charts, or the Advanced Process Library (APL) from PCS 7 V9.0 SP2 to V9.0 SP1 is technically impossible and explicitly unsupported by Siemens. Once a project database, CFC chart, or block library is converted to V9.0 SP2, its internal schema cannot be opened or downgraded in V9.0 SP1. The correct and supported solution is to upgrade the Engineering Station (ES) from V9.0 SP1 to V9.0 SP2. Crucially, Service Packs within the same major/minor release do not require new software licenses: your existing SIMATIC PCS 7 V9.0 engineering license covers V9.0 SP2 completely, requiring only the installation of the V9.0 SP2 software media.

Executive Summary

System integrators and plant engineers occasionally receive PCS 7 project archives created with a higher Service Pack (such as PCS 7 V9.0 SP2) while their local Engineering Station (ES) is installed with an earlier revision (such as V9.0 SP1). Confronted with version incompatibility dialogs upon opening the project, engineers often seek methods to downgrade the project, CFC components, or APL libraries back to V9.0 SP1. This article clarifies the one-way database architecture of SIMATIC PCS 7, confirms the impossibility of software downgrades, and explains the zero-cost licensing rules for upgrading an ES to matching Service Packs.

Architecture and Fundamental Mechanics

The SIMATIC PCS 7 engineering database relies on a complex relational data architecture comprising STEP 7 project tables, Microsoft SQL Server database schemas, and CFC/SFC technological manifests. When a project is created or saved in PCS 7 V9.0 SP2:
1. CFC and SFC Database Schemas: The internal chart compiler and connection models are upgraded to the V9.0 SP2 format. This format incorporates new block attributes, enhanced type-instance synchronizers, and updated module driver rules.
2. Advanced Process Library (APL) Types: APL blocks in V9.0 SP2 include updated interface structures, modified feature bits, and improved algorithmic routines. Function blocks (FBs) and technological types (Control Module Types - CMTs) reference internal library identifiers unique to SP2.
3. Backward Incompatibility: Siemens engineering environments enforce a strict forward-only database migration model. STEP 7 and CFC possess no reverse compiler or schema downgrade translation filters. Attempting to open a V9.0 SP2 project in V9.0 SP1 triggers fatal version mismatch errors.

Software Licensing Architecture:
Siemens software licensing operates on major release boundaries (e.g., V8.x to V9.0). Service Packs (SP1, SP2, SP3) and Update Collections (UC) are maintenance enhancements that share the identical license key. A valid license key for SIMATIC PCS 7 Engineering V9.0 validates V9.0, V9.0 SP1, V9.0 SP2, and V9.0 SP3 interchangeably in the Automation License Manager (ALM).

Step-by-Step Implementation Procedure

Verify Active License Entitlements in ALM:
a. On the Engineering Station, open the Siemens Automation License Manager (ALM).
b. Inspect the installed engineering licenses (e.g., PCS 7 Engineering V9.0).
c. Confirm that the license version designates 'V9.0'. Note that no separate license is required for Service Pack 2.
Obtain Official PCS 7 V9.0 SP2 Installation Media:
a. Download the official SIMATIC PCS 7 V9.0 SP2 installation packages from the Siemens Industry Online Support (SIOS) download portal.
b. Alternatively, obtain the official installation DVD/ISO media pack from your plant software repository or authorized Siemens distributor.
Backup Engineering Station Environment:
a. Create a complete system image backup of the Engineering Station (via Acronis, Veeam, or virtual machine snapshot if virtualized under VMware/SIVaaS).
b. Archive all active STEP 7 and PCS 7 projects using SIMATIC Manager File -> Archive....
Execute Software Upgrade to PCS 7 V9.0 SP2:
a. Insert or mount the PCS 7 V9.0 SP2 installation ISO.
b. Launch Setup.exe with administrative privileges.
c. Select 'Update' as the installation mode.
d. The installer automatically detects installed V9.0 SP1 components (STEP 7, CFC, SFC, WinCC, APL) and updates them to V9.0 SP2 while preserving existing engineering licenses and system settings.
e. Restart the computer upon completion of the installation.
Open and Verify the V9.0 SP2 Project:
a. Launch SIMATIC Manager.
b. Open the V9.0 SP2 multiproject: confirm it opens cleanly without version incompatibility prompts.
c. Open the Master Data Library and CFC charts to confirm all APL block types display full synchronization.

Verification

Launch the installed software utility (s7aversx.exe) or open SIMATIC Manager Help -> About: verify that the version string reports SIMATIC PCS 7 V9.0 SP2.
Open any CFC chart containing APL blocks: select Chart -> Compile -> Chart as Program... and confirm incremental compilation succeeds with 0 errors.
Open Automation License Manager (ALM): confirm that all PCS 7 licenses display 'OK' status without license violation warnings.
Check WinCC Explorer: open the OS project and verify that the WinCC version reports V7.4 SP1 Upd7 or the corresponding V9.0 SP2 package baseline.

Limitations and Operational Precautions

Never attempt to force-copy older V9.0 SP1 block libraries into a V9.0 SP2 project database; doing so creates hybrid block interface inconsistencies that corrupt CFC charts and cause compilation aborts. Upgrading the ES to V9.0 SP2 requires ensuring that redundant OS servers and clients are also scheduled for upgrade if utilizing new SP2 features online. Media package procurement should be coordinated through an authorized Siemens distributor or the Siemens Industry Mall.

Engineer FAQ

Can I export CFC charts to XML/CAx and import them into PCS 7 V9.0 SP1?

While technological CAx/XML transfer can move raw block data, any block type or attribute unique to SP2 will be rejected or corrupted upon import into SP1, making it impractical for production code.

Do I need to buy a new license to upgrade from V9.0 SP1 to V9.0 SP2?

No. Upgrades between Service Packs within the same major version (V9.0) are covered by the existing V9.0 license; no additional license purchase is necessary.

Can an ES running V9.0 SP2 download to an AS running V9.0 SP1 blocks?

Yes, provided the block types in the AS controller are not updated to SP2 interfaces. However, keeping the ES, AS, and OS on matching Service Packs is recommended.

Where can I download the PCS 7 V9.0 SP2 update software?

From Siemens Industry Online Support (SIOS) under the official SIMATIC PCS 7 V9.0 SP2 software delivery release entry.

What happens if I try to open a V9.0 SP2 project on a V9.0 SP1 machine?

SIMATIC Manager displays a blocking error stating that a required software package (e.g., CFC V9.0 SP2) is missing or of a newer version, aborting the open operation.