Engineering Station Workflow and Project Format Constraints When Operating Older CFC Software with Newer Licenses

When maintaining legacy SIMATIC PCS 7 engineering stations (such as PCS 7 V8.1) using newer software licenses (such as CFC V9.0), engineers must separate software authorization from project database formatting. While Automation License Manager (ALM) seamlessly validates CFC V8.1 using a V9.0 license key, opening the project on a newer PCS 7 V9.0 engineering station will trigger an irreversible database format upgrade. Once upgraded to V9.0 format, the project cannot be opened, edited, or delta-downloaded from the V8.1 station. Always maintain dedicated virtual machines for legacy engineering, preserve master project backups, and confirm upgrade paths with an authorized Siemens distributor or the Siemens Industry Mall.

Executive Summary

In complex manufacturing plants with multiple automation generations, engineering teams often manage a mixed fleet of PCS 7 versions (e.g., running PCS 7 V8.1 on existing process lines while adopting PCS 7 V9.0 for new facilities). When new commercial software packages deliver V9.0 licenses, engineers frequently deploy these licenses across legacy engineering stations. While ALM's downward license compatibility enables older software to run seamlessly, significant operational risks arise when project archives are opened across different software environments. This guide details practical engineering station workflows, project database format barriers, and delta download compatibility rules.

Architecture and Fundamental Mechanics

The operational architecture governing mixed-version engineering environments involves three distinct domains:
1. License Authorization Domain:
The licensing layer is completely decoupled from project binary storage. An engineering station running CFC V8.1 SP1 queries ALM for authorization. Because ALM supports backward compatibility, the V9.0 license satisfies the check. The software runs with 100% of its native V8.1 capabilities.
2. Project Database Format Domain:
The CFC and SFC database schemas evolve across major PCS 7 releases. In PCS 7 V8.1, CFC charts are stored using internal schema V8.x. When that project is opened on an engineering station running PCS 7 V9.0 software, the system displays a mandatory prompt: 'The project will be converted to the current format'. If the user confirms, the chart database headers, block descriptors, and type references are rewritten to V9.0 schema. This conversion is one-way and irreversible; PCS 7 V8.1 cannot parse V9.0 project databases.
3. Controller Online Download Domain:
If a project is converted to V9.0 on a newer ES, downloading changes to a running AS that was originally configured with V8.1 system libraries can trigger block conflict errors or require an entire AS STOP download. Maintaining dedicated, version-isolated engineering environments is vital to operational continuity.

Step-by-Step Implementation Procedure

Establish Version-Isolated Engineering Virtual Machines:
a. Do not attempt to install multiple PCS 7 versions on a single Windows operating system (side-by-side installation is unsupported).
b. Create dedicated virtual machines (using VMware Workstation or Microsoft Hyper-V) for each major PCS 7 release (e.g., VM_PCS7_V81_PlantA and VM_PCS7_V90_PlantB).
Configure Centralized Floating License Management:
a. Install Automation License Manager on a central network server or the host PC.
b. Store all license keys (including CFC V9.0, STEP 7 V9.0, and WinCC V7.4/V7.5) on the central ALM server.
c. On each engineering virtual machine, configure ALM to point to the central license server (Edit -> Connect Computer).
d. Both V8.1 and V9.0 virtual machines will acquire authorization seamlessly from the V9.0 license pool.
Enforce Strict Project Archiving and Access Controls:
a. Before opening any legacy project, generate a timestamped archive (File -> Archive) and store it in write-protected storage.
b. Clearly label project folders with their native PCS 7 version (e.g., ProjectX_V8.1_SP1_DoNotOpenInV9).
Handling Accidental Database Upgrade Prompts:
a. If an engineer accidentally opens a V8.1 project on a V9.0 engineering station, STEP 7 displays a prompt warning that the project format will be adapted.
b. Click 'Cancel' immediately to preserve the legacy database format.
c. If the project must be permanently migrated to V9.0, execute a complete migration review, update library blocks from the Master Data Library, and schedule an AS STOP maintenance window if required.

Verification

In the V8.1 engineering station, open SIMATIC Manager: verify that the project opens without format warning prompts.
In CFC, open a chart: verify that blocks and cross-references display without corruptions.
Execute a delta compilation (Chart -> Compile -> Changes only): verify that the compiler generates code cleanly.
Check online connection: verify that online test mode functions and monitors live values in the AS controller.

Limitations and Operational Precautions

Converting a legacy CFC project to a newer PCS 7 version cannot be undone. Downgrading a project back to an older format is not supported by Siemens tools and requires completely re-engineering the application from scratch or restoring backups.

Engineer FAQ

Can I install PCS 7 V8.1 and PCS 7 V9.0 on the same computer?

No. Side-by-side installations of different PCS 7 versions on the same operating system are strictly unsupported and will corrupt system shared files. Use virtual machines.

What happens if I accidentally click 'Yes' to convert a project to V9.0?

The project database format is upgraded permanently. It cannot be opened again in PCS 7 V8.1. You must restore your pre-upgrade backup archive.

Can a centralized ALM server distribute V9.0 licenses to V8.1 clients?

Yes. ALM supports network floating licenses; client stations across the network can draw licenses from the central server.

Does compiling a V8.1 project using a V9.0 license require an AS STOP?

No. The license key has zero impact on controller runtime code. As long as the engineering software is V8.1, compiled blocks remain fully compatible with V8.1 controllers.

How do I identify the native PCS 7 version of an archived project?

Open the project directory in Windows Explorer, locate the CONENPRJ or s7p file, or open it in SIMATIC Manager and inspect project properties under 'Required Software'.