Resolving WinCC V7 SP3 PowerTag License Exceeded Errors

Problem Description

When configuring a WinCC V7 SP3 (or V7.3 SP3) project that communicates with an S7-300 CPU via TIA Portal V13 SP1 Update 9 and Classic PLCSIM, operators frequently encounter persistent red status messages in the Tag Management pane. The classic symptom reported in the field is two red-line comments appearing next to a newly created boolean memory bit external tag, even though the project contains only a handful of tags and the runtime connection status reports "OK".

Common red-line messages observed in WinCC V7 include:

• Number of tags exceeds license capacity
• License mode: insufficient PowerTags
• License invalid or missing
• Tag cannot be used in runtime
• License mode: RT (when an RC or ES license is expected)
• Demo mode watermark in the project title bar

Standard remediation attempts - deleting and reinstalling license keys through the Automation License Manager (ALM), uninstalling and reinstalling WinCC, or even wiping the ALM database - typically do not resolve the problem. This is because the root cause is rarely the license media itself. The cause is almost always the configuration of the project relative to the license tier that has been purchased.

Root Cause Analysis

WinCC V7 uses a counted PowerTag licensing model. Every external tag, every archive tag, and (in some project configurations) certain internal tags count against the licensed PowerTag pool. The minimum purchasable license tier is 128 PowerTags. Tiers double at 256, 512, 1024, 2048, 4096, 8192, 16384, and 65536 PowerTags.

The two red-line messages shown in the operator's screenshots indicate that the project references more PowerTags than the installed license can service. Reinstalling the license, uninstalling WinCC, or moving the license between dongle and host does not help, because the configuration of the project itself is the limiting factor, not the license media.

Three root-cause families produce these symptoms in practice:

1. Insufficient license tier - The RT or RC license installed covers fewer PowerTags than the project references. A 128-PowerTag RC license cannot service a project that imports 300 external tags from the PLC symbol table.
2. License type mismatch - A Runtime-only (RT) license is installed, but the Engineering System (ES) components are also being invoked. RT licenses authorize runtime use of the project only; ES features require an RC or ES license.
3. Phantom tags from TIA Portal AS-OS engineering - When TIA Portal V13 SP1 is used to compile the S7-300 program, the HMI tag table can be merged with the PLC tag table. This process can add more external tags than are visible in the original WinCC Tag Management. Symbols that exist only for PLC-internal logic are inadvertently imported into the HMI.

A fourth, less common cause is a corrupted ALM database, but this typically produces different symptoms (e.g., License server not found at WinCC startup) rather than the two red-line tag comments described in the original incident.

PowerTag Licensing Model in WinCC V7

WinCC V7 licenses are sold in fixed PowerTag tiers. The license key, delivered either as a software license (soft license) bound to a host ID, or on a USB hardware dongle (referred to in some regional price lists as AX NF ZZ), binds a single WinCC instance to a specific PowerTag count.

The available PowerTag tiers are:

A 16-bit tag, an 8-bit tag, and a 1-bit boolean all count as one PowerTag. Structured tags and array tags each count as one PowerTag per element, not per structure. WinCC V7 does not differentiate between read and write tags for licensing purposes.

Which Tags Count?

The following tag types count against the PowerTag pool:

• External tags (S7 Protocol Suite, OPC, named connection, Modbus, Allen-Bradley DF1, etc.)
• Archive tags (process and alarm archives configured in Tag Logging)
• Internal tags used in logging (some project configurations)
• Tags used in the user archive
• Tags used in the S7 connections that use symbolic addressing

The following do NOT count:

• Local script variables in C and VBS
• Internal tags used only for faceplate switching
• Color variables used in dynamic dialogs
• Pointer variables in C-scripts (unless they are tied to a tag)

Reference: Siemens WinCC V7.4 SP3 - Licensing

License Types: RC, RT, ES, and Client

Siemens sells WinCC V7 in four primary license bundles. Mixing license types in a single project is one of the most common causes of the "license exceeded" red-line state, especially when the project is moved between developer machines and production machines.

An RC license includes both the WinCC Explorer and the runtime. It is the standard choice for single-station projects.

An RT license allows only the runtime. If the user opens WinCC Explorer or any of the editors with an RT license, the project enters License mode: RT and many tag types become unwritable in the editor, although they may still appear in the runtime database.

An ES license is sold with development toolchains. It is not designed for production runtime but can be used for development, FAT testing, and simulation environments.

A Client license authorizes a WinCC client to connect to an existing WinCC server over the network. Client licenses do not count toward the server's PowerTag total.

The user in this scenario is running WinCC in Runtime mode against Classic PLCSIM, so an RT license would technically authorize the runtime. However, if the project was opened or modified in the WinCC Explorer (which is required to create the test tag described in the original post), an ES or RC license is required to compile the runtime database. This is the single most common reason a freshly created project shows red-line license warnings even when no PLC has been connected.

Reference: Siemens Automation License Manager (ALM) - Operating Manual

Diagnosing Tag Count in Tag Management

The exact number of PowerTags in the project must be measured before a license upgrade can be sized. WinCC V7 exposes the PowerTag count in two locations, and both must be cross-checked because they can differ during a partial compile.

Method 1: Status Bar in WinCC Configuration Studio

1. Open the WinCC Configuration Studio (Start > Siemens Automation > WinCC > WinCC Configuration Studio).
2. Navigate to the Tag Management node.
3. Look at the bottom-right status bar. It displays the current PowerTag consumption in the format PowerTags: NNN / MMM, where NNN is the number of tags in use and MMM is the number of tags licensed.

Method 2: ALM-Powered License Status

1. Open the Automation License Manager (Start > Siemens Automation > Automation License Manager).
2. Locate the WinCC V7 license under the host node.
3. Right-click the license and select Show License Information.
4. The Used PowerTags field shows the current project consumption as reported by ALM.

The two methods will report slightly different numbers if WinCC is in a state of partial compilation. Always trust the Configuration Studio status bar during an active build cycle, and use the ALM value for license audit purposes.

Step-by-Step Resolution Procedure

Follow this procedure in order. Do not skip steps, because the ALM and the project must be in a known-good state before the cause of the red-line messages can be isolated.

Step 1 - Capture the Baseline

1. Open the WinCC project in the WinCC Explorer.
2. Open the WinCC Configuration Studio and navigate to Tag Management.
3. Record the PowerTag count shown in the status bar (e.g., PowerTags: 47 / 128).
4. Open the ALM and screenshot the installed license, including the article number, license tier, validity date, and host ID.
5. Save a copy of the project using WinCC Explorer's Project > Save As with a timestamp suffix so the working state is recoverable.

Step 2 - Verify the License Tier

Compare the project's PowerTag count to the license tier shown in the ALM. If the project exceeds the license tier, the red-line message is expected. Proceed to Step 3 to confirm.

If the project does NOT exceed the license tier, the issue is elsewhere. Jump to the Diagnostics Matrix section below.

Step 3 - Audit Tags in Use

1. In the WinCC Configuration Studio, expand the Tag Management tree.
2. For each connection (S7, OPC, etc.), list the number of external tags in the right-hand pane.
3. In the Alarm Logging node, list the number of message tags and the number of archive tags per archive.
4. In the User Archive node, list the number of fields. Each user archive field counts as one PowerTag.
5. In the Tag Logging node, list the number of archive tags and check whether the Use internal tags for logging flag is enabled.
6. Sum the totals. This is the project's true PowerTag consumption.

A common gotcha is that internal tags created in WinCC are NOT counted against the PowerTag pool, but if the user has ticked Use internal tags for logging in the project's properties, they DO count. Check the project's properties for this setting.

Step 4 - Choose the Correct License Tier

Match the audited PowerTag consumption to the next available tier. Always size the license with 20 to 30 percent headroom for future expansion. A 128-PowerTag license is not a cost-effective choice for a 300-tag project; the 512-tier is the correct minimum.

Step 5 - Apply the License

1. If using a soft license, log in to the Siemens License Server (WIBU CodeMeter or SPLM, depending on region) and download the upgraded license to the host.
2. If using a USB dongle, contact your Siemens sales representative with the existing dongle's serial number. They will issue a new license file (.LIC) to be transferred to the dongle using the ALM's Write License to USB Dongle function.
3. Open the ALM and confirm the new tier is recognized by checking the license detail pane.
4. Restart the WinCC runtime.

Step 6 - Recompile the Project

In the WinCC Explorer, right-click the project node and select Rebuild. This forces WinCC to re-validate the runtime database against the new license tier. The red-line messages in the Tag Management should clear. If they do not, the issue is in Step 3 (audit) and additional tags must be removed or the license upgraded again.

Automation License Manager (ALM) Operations

The ALM is the only tool authorized to read, write, and manage Siemens software licenses. It is installed automatically with WinCC V7 and is also available as a standalone install from the Siemens SIOS portal.

Starting the ALM

The ALM can be launched in two ways:

• Start > Siemens Automation > Automation License Manager
• From the WinCC Explorer: Options > Licenses

License Storage Media

USB dongles in the AX NF ZZ family are regional designations. In the EU, they are commonly the "Siemens USB License Key" with article numbers in the 6ES7652-0XX00-1XD0 range. Confirm the exact article number for your region with your Siemens sales channel.

Common ALM Operations

• View installed licenses - right-click a host or dongle and select Show License Information.
• Transfer license between media - right-click the license and select Move License or Copy License. This is sometimes called "re-hosting" and is rate-limited per Siemens' EULA.
• Reinstall corrupted licenses - right-click the dongle or host and select Reinstall License.
• Generate license report - Help > Save License Information. This produces a text file that can be sent to Siemens support.
• Repair the ALM database - stop the ALM service, rename C:\ProgramData\Siemens\Automation\License Manager\almservice.mdb to .bak, then restart the ALM service. It will rebuild the database on the next launch. The same repair approach used for Autodesk and Microsoft Office licensing services applies in principle: stop the service, remove the corrupted state, restart. Reference: Autodesk Licensing Error Resolution for the comparable service-repair procedure on a different vendor's licensing service.

Reference: Automation License Manager (ALM) Operating Manual

State Diagram: License Validation in WinCC V7

TIA Portal V13 SP1 and PLCSIM Integration

The original incident uses TIA Portal V13 SP1 Update 9 with Classic PLCSIM. This is a supported but specific configuration that introduces its own licensing considerations beyond the WinCC PowerTag pool.

TIA V13 SP1 Update 9 Limitations

TIA Portal V13 SP1 supports the CPU 300/400 and the S7-300 family natively. The V13 SP1 cycle is end-of-life for new license sales, but maintenance, license transfers, and KB articles are still available. The V13 SP1 Update 9 patch is the last released update for that branch. Modern WinCC V7 SP3 projects should ideally be paired with a current TIA Portal version (V16 or later) for the S7-300 family, but the V13 SP1 Update 9 + WinCC V7 SP3 combination is fully supported and remains in widespread use.

Classic PLCSIM Behavior

Classic PLCSIM (the pre-TIA-PLCSIM V14 product) simulates an S7-300 CPU on the same host that runs TIA Portal. WinCC can connect to PLCSIM over the S7 Protocol Suite's TCP/IP channel using the local loopback address (127.0.0.1) on the default ISO-on-TCP port (102).

When WinCC starts a runtime that targets PLCSIM, the runtime database is downloaded and PLCSIM exchanges process values with WinCC over TCP. The runtime does not need a physical PLC, but it does need a valid PowerTag license.

Connection Parameters for S7 Protocol Suite

Common Pitfalls When Mixing TIA and WinCC

• Symbolic vs. absolute addressing - When TIA Portal exports the S7-300 symbol table, WinCC may import the symbols as new external tags. This is the most common cause of the "phantom tag" scenario described in the Root Cause section.
• Re-imports on every compile - If the HMI tag table is configured to auto-sync with the PLC tag table, each TIA compile will add tags. If the PLC has hundreds of internal flags used for non-HMI logic, the HMI may pull them in by mistake.
• Optimized block access - S7-300 data blocks in optimized access mode expose a different symbol structure to TIA. WinCC V7 SP3 handles this correctly, but the S7 Protocol Suite may need its Symbolic Access option enabled in the channel diagnostics.

Reference: Siemens WinCC V7.4 SP3 Manual

Verifying the Fix

After applying the corrected license tier and recompiling the project, perform the following checks in order.

1. Visual check - Open the Tag Management in the WinCC Configuration Studio. The red-line messages should be replaced by either no message (license sufficient) or a green "OK" message.
2. Status bar check - The status bar should show PowerTags: NNN / MMM where NNN is less than MMM.
3. Runtime startup - Start the WinCC runtime. The startup screen should not display any license warnings.
4. PLCSIM connection - Confirm that the boolean memory bit toggles in the WinCC graphics when the corresponding bit is toggled in PLCSIM. Use the WinCC tag simulator if a PLC connection is not present.
5. ALM audit - Open the ALM and verify the new license tier is still active. Restart the host to confirm the license persists across reboots.

Common WinCC License Error Messages

The SPLM error message above is borrowed from the comparable Siemens NX licensing workflow. NX uses the SPLM (Siemens Product License Management) server for network floating licenses, and WinCC V7 supports the same mechanism for large multi-user installations. Reference: Siemens NX SPLM License Server Error (note: this is a Siemens community thread, use only as a vendor-wide context reference, not as a citation).

Diagnostics Matrix

Use this matrix to triage license issues before contacting Siemens support.

Preventive Measures

To avoid returning to the "license exceeded" state after a successful fix, adopt the following practices.

1. Maintain a 25 percent PowerTag headroom in the license tier. This gives engineering room to add tags during commissioning without re-licensing.
2. Document the licensed PowerTag count in the project header comments. Future engineers need to know the limit.
3. Lock the TIA-HMI tag sync to manual mode. Auto-sync is convenient but tends to add tags on every PLC compile.
4. Back up the ALM database to a known location. The default path is C:\ProgramData\Siemens\Automation\License Manager\.
5. Track license re-hosts in a centralized log. Siemens allows a limited number of re-hosts per license; running out of re-hosts requires purchasing a new license.
6. Use the WinCC Tag Simulator for test projects. The simulator provides 16 internal tags that do not count against the PowerTag pool, allowing tag structure testing without consuming license capacity.
7. Standardize the license tier across the fleet. Mixing tiers (some machines at 128, others at 1024) makes spare-parts management and license reallocation harder than picking one tier per cell.

Reference: Siemens License Management Best Practices

Advanced: SPLM Network Licensing

For large WinCC V7 installations, Siemens provides the SPLM (Siemens Product License Management) server for floating network licenses. The same workflow used to fix NX license errors (set the SPLM_LICENSE_SERVER environment variable to point at the SPLM server) applies to WinCC V7 with a network license.

To configure SPLM for WinCC V7:

1. Install the SPLM server on a dedicated Windows host with a static IP.
2. Install the SPLM client component on every WinCC runtime host.
3. Set the SPLM_LICENSE_SERVER system environment variable to the SPLM server hostname.
4. Restart the runtime host. WinCC will now pull a floating license from the SPLM server at startup and release it at shutdown.

Floating licensing is the right choice when you have more than ten WinCC stations but less than the total PowerTag count requires. Each station needs a license only while its runtime is active.

Migration to WinCC V7.4 / V7.5

If the license tier is approaching its limit and the project is stable, consider migrating to WinCC V7.4 or V7.5. Both versions support the same PowerTag tier model, but V7.4 SP3 and later include:

• Improved ALM integration that surfaces license issues earlier in the build cycle.
• OPC UA server as a native channel, reducing the PowerTag count consumed by OPC bridging.
• Improved S7-1500 support, useful when migrating from S7-300 to S7-1500 hardware.

The migration path from V7.3 SP3 to V7.4 SP3 is in-place. Open the V7.3 project in V7.4 Explorer and the project is upgraded automatically. The license is reusable across versions, but the license media (dongle or soft license) must be updated by the Siemens License Server.

Reference: Siemens WinCC V7.5 Release Notes

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