Resolving 'Missing PCS 7 WinCC License' Errors Caused by Standalone WinCC License Mixing

In SIMATIC PCS 7 V7.1, license violation popups reporting missing 'PCS 7 WinCC' and 'WinCC RC PO' licenses occur when standalone WinCC Runtime/Configuration licenses (e.g. WinCC RC 20000) are installed on an OS Server. PCS 7 Operator Stations enforce dedicated 'SIMATIC PCS 7 OS Software' and 'OS RT PO' licenses and reject standalone WinCC tags. Resolve this by removing the standalone WinCC keys and installing the proper PCS 7 OS Server and Process Object licenses in Automation License Manager.

Diagnostic Overview and Commercial Licensing Conflict

During on-site commissioning or maintenance of a plant running SIMATIC PCS 7 V7.1 SP2, engineers frequently encounter persistent license fault dialogs on redundant OS Servers or the Central Archive Server (CAS):
* The system displays an error prompt stating: Missing license: SIMATIC PCS 7 WinCC or missing WinCC RC PO.
* The commissioning team inspects Automation License Manager (ALM) and confirms that a large license—such as WinCC RC PO (20000)—is actively installed and validated as 'OK'.
* Despite the presence of the 20,000 tag/PO license key, WinCC Runtime periodically triggers non-compliance warning popups and enters demo mode behavior.

This fault typically occurs in facilities operating both standalone SCADA systems (SIMATIC WinCC V7.0) and distributed control systems (SIMATIC PCS 7). During software setup or license consolidation, license keys from a standalone WinCC project are inadvertently transferred to the PCS 7 OS Server, or an engineer orders a standard WinCC RC package instead of the mandated PCS 7 OS package.

Because SIMATIC WinCC serves as the graphical visualization engine within PCS 7, engineers assume that standard WinCC licenses satisfy PCS 7 requirements. In reality, Siemens enforces distinct, non-interchangeable licensing schemas between standalone WinCC and PCS 7 OS.

Standalone WinCC vs. PCS 7 OS Licensing Enforcement

The technical and legal boundary between standalone WinCC and PCS 7 OS centers on architecture and counting algorithms:

Standalone WinCC Licensing (PowerTags):
* Standalone WinCC licenses are priced based on PowerTags (process variables connected to external automation devices, e.g. 512, 2048, 65536 tags).
* Key products: WinCC RT (Runtime) or WinCC RC (Runtime and Configuration).
SIMATIC PCS 7 OS Licensing (Process Objects):
* PCS 7 OS does not license individual raw variables. It licenses Process Objects (PO), representing complete technological equipment models (e.g. MotL, VlvL, PIDConL, Pcs7AnIn). One Process Object encapsulates dozens of internal WinCC tags, message definitions, and faceplate connections.
* Required Base License: SIMATIC PCS 7 OS Software Server V7.1 (e.g. MLFB 6ES7658-2BA17-0YA0).
* Required Capacity License: SIMATIC PCS 7 OS Runtime Process Objects (e.g. cumulative PO tiers: 100, 1000, 5000 PO).
* Required Options: WinCC Server Redundancy and dedicated Central Archive Server (CAS) runtime licenses.
Runtime License Check Mechanism:
* When WinCC activates inside a project compiled from SIMATIC Manager, the runtime engine checks the internal project header flag PCS7_Project = 1.
* Upon detecting a PCS 7 project, WinCC bypasses standard PowerTag license checks and explicitly queries ALM for the cryptographic token SIMATIC PCS 7 OS.
* If ALM contains only WinCC RC 20000, the query fails. The standalone license remains unconsumed, and WinCC alerts for missing PCS 7 entitlements.

Step-by-Step License Re-Alignment and Verification

1. Audit Installed License Keys in Automation License Manager

Launch Automation License Manager (ALM) on OS Server A and Server B.
Select drive C: and click View > Details.
Identify all installed license tokens:
* Look for standalone tokens: WinCC RC ... or WinCC RT ....
* Look for PCS 7 tokens: SIMATIC PCS 7 OS Software Server and SIMATIC PCS 7 OS RT PO.
Note which licenses were incorrectly transferred from the standalone WinCC project.

2. Remove / Transfer Standalone WinCC Keys

Connect a USB license transfer drive to the server.
In ALM, select the standalone WinCC RC PO (20000) license key.
Drag and drop the license to the USB drive to return it to the standalone SCADA environment.

3. Install Legitimate PCS 7 OS Server and PO Licenses

Transfer the proper PCS 7 OS license keys to the local hard drive:
* SIMATIC PCS 7 OS Software Server V7.1
* SIMATIC PCS 7 OS Runtime (PO ...) (matching your plant's compiled PO count).
* SIMATIC WinCC Redundancy (required on BOTH redundant servers).
* For the CAS node: SIMATIC PCS 7 Central Archive Server.
In ALM, right-click the transferred keys and select Check. Confirm all keys show a green checkmark with status Valid.

4. Recalculate OS Process Object Consumption

In SIMATIC Manager on the Engineering Station, select the OS project.
Select menu Options > PCS 7 License Information....
Review the OS Process Objects tab:
* Note the number of Configured POs vs. Licensed POs.
* Confirm that the installed license count strictly exceeds the compiled PO count.
Execute PLC > Compile and Download Objects (Compile OS).
Restart WinCC Runtime on the OS Server; verify zero license fault popups appear.

WinCC Standalone vs. PCS 7 OS Licensing Matrix

Software AttributeStandalone SIMATIC WinCC V7.xSIMATIC PCS 7 OS V7.xLicensing CompatibilityPrimary MetricPowerTags (Raw external I/O bits/words)Process Objects (PO) (Technological blocks)Incompatible metricsServer Base LicenseWinCC Server V7.xSIMATIC PCS 7 OS Software ServerStandalone key rejected by PCS 7Engineering LicenseWinCC RC V7.xSIMATIC PCS 7 Engineering V7.xStandalone RC rejected by PCS 7Redundancy LicenseWinCC Redundancy V7.xWinCC Redundancy (Required on both nodes)Identical underlying ALM tokenCentral Archive (CAS)WinCC/CAS OptionSIMATIC PCS 7 Central Archive ServerDedicated PCS 7 CAS token required

Verification

In Automation License Manager, select drive C:; confirm SIMATIC PCS 7 OS Software Server displays status Valid.
Activate WinCC Runtime on the OS Server.
Observe the system for 30 minutes; confirm that no 'Missing License' modal dialogs or Windows Application Event Log license warnings occur.
On the Central Archive Server (CAS), confirm the CAS service initializes with green status indicators in the management console.
In SIMATIC Manager, verify Options > PCS 7 License Information reports Status: OK with zero Process Object deficits.

Limitations and Operational Precautions

Redundant Server Parity: Redundant OS servers must have identical license keys installed on each physical machine. A single server license cannot be shared or split across a redundant server pair.
Never Use License 'Cracks' or Bypasses: Using unauthorized license patching utilities compromises plant cyber integrity, invalidates warranty coverage, and risks unexpected SCADA shutdown during runtime.
Commercial and Licensing Notice: When scoping licensing corrections or expanding Process Objects, always validate exact order numbers (MLFBs) and license counts against the official Siemens ST PCS 7 catalog and consult an authorized distributor for official quotation.

Engineer FAQ

Can a WinCC RC license be upgraded to a PCS 7 OS license?

No direct cross-upgrade license exists between standalone WinCC and PCS 7 OS. A dedicated PCS 7 OS Software Server and Process Object package must be acquired.

Why did the system report missing WinCC RC PO if WinCC RC was already installed?

Because the project is a PCS 7 project. The runtime engine queries specifically for PCS 7 OS Process Object tokens. Finding standard WinCC RC tags, it rejects them and issues an alarm for missing PCS 7 PO licenses.

What happens if a PCS 7 plant runs with missing OS PO licenses?

WinCC enters demo mode: a persistent license warning banner is superimposed across the screen, and periodic popups require operator dismissal, distracting control room staff.