Determining WinCC Project Tag Count Before License Upgrade

When an engineer inherits a Siemens WinCC V7 project file from another site, contract partner, or archive, a recurring problem is that the local WinCC installation carries a smaller Power Tag license than the project itself. WinCC refuses to enter Runtime and the WinCC Explorer editor closes after one hour in demo mode if the licensed Power Tag quantity is below the project's required count. Before purchasing an upgrade, the engineer must quantify how many tags the source project actually references so that the correct tier of Power Tag license (128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 100000, 150000, 256000) can be acquired.

This reference consolidates the procedures documented in the WinCC V7.3 General Information and Installation manual and the WinCC licensing FAQ 109480488, together with field-proven workarounds for tag-count discovery when the local license is undersized for the source project.

1. Power Tag Licensing Architecture in WinCC V7

WinCC V7 separates tag licensing into two categories:

• Internal tags — not counted against the Power Tag license. These are calculated or local variables used inside the HMI project (arithmetic tags, script-internal variables). The quantity of internal tags is unlimited in every configuration.
• External tags (Power Tags) — variables that map to a process connection (S7 PLC, Modbus, OPC, Allen-Bradley, PROFIBUS, etc.). Each Power Tag consumes one license unit. The licensed total is enforced at Runtime startup.

Power Tag license counts are issued in fixed binary steps plus a few high-end blocks:

2. Demo Mode Behavior When License Is Undersized

Per the WinCC V7.3 installation manual 102777629, missing or undersized Power Tag licenses trigger a defined demo-mode fallback rather than a hard failure. The exact response depends on which license is missing:

2.1 Missing RC (Runtime + Configuration) license

If the WinCC Explorer and editor license does not match the project, the editors terminate after one hour of demo mode. During that hour the project can still be opened, edited, and saved. This window is the most efficient way to inspect tag counts without first buying a license.

2.2 Missing RT (Runtime) license

If only the Runtime license is undersized, a red message window appears on Runtime start. The dialog prompts the user to acquire a valid license and must be acknowledged. The dialog re-appears every 10 minutes and must be acknowledged each time. If the operator moves the dialog, it re-centers itself after at most 30 minutes. The WinCC Explorer is not terminated while Runtime is running; the Explorer is closed only when Runtime exits.

2.3 No license at all

Without any WinCC license, the operational processing remains fully functional (archiving and message system continue without data loss), but the WinCC Explorer is also closed once the demo hour expires. The project can still be used in this state long enough to inspect tag counts.

3. Reading the Tag Count in WinCC Explorer (Status Bar Method)

The most direct field method is documented in the Siemens WinCC FAQ 109480488. It does not require any external script or file inspection — only the WinCC Explorer already installed on the engineering station.

3.1 Procedure

1. Start the WinCC Explorer of the version that matches the project (WinCC V7.0, V7.2, V7.3, V7.4, or V7.5). Version mismatch is one of the most common reasons a project refuses to load.
2. From the File > Open menu, select the project file (*.MCP) and load it. If the local Power Tag license is below the project's requirement, the project still opens in demo mode for one hour.
3. In the left-hand navigation tree, locate the Tag Management node. Do not double-click it to expand; single-click only.
4. Look at the status bar at the bottom of the WinCC Explorer window. WinCC prints the count of external tags in use, for example: External tags: 1824 (internal tags are shown on a separate counter).
5. Record the count. Round up to the next license tier when ordering. A project that uses 1824 external tags requires the 2048 Power Tag license.
6. Close the project without saving to preserve the original file timestamps.

3.2 Why single-click is sufficient

WinCC loads the tag database fully when the project is opened, so the tag count is known to the Explorer before the Tag Management editor is expanded. Expanding the editor (double-click) is not required to read the count; the single-click only selects the node so that the status bar refreshes with the relevant statistics. This avoids touching the configuration tree and reduces the risk of an inadvertent "save" that could mark the project as modified.

4. Reading the Tag Count from the Project File Directly

For engineers who cannot open the project at all — for example when only a .MCP archive backup is available and no WinCC installation of the matching version is reachable — the project file can be inspected with a text editor. WinCC V7 stores tag metadata inside the project database; the count can be derived from the exported tag list or from the compressed .MCP archive.

4.1 Inspect the .MCP archive

1. Rename MyProject.MCP to MyProject.ZIP (an .MCP file is a PKZip-compatible container in WinCC V7).
2. Extract the archive with any ZIP utility.
3. Open the file TagManagement.xml (or the legacy TagManagement binary file in V7.0/V7.2) inside the extracted tree. Search for the XML element <Tag> — each occurrence is one external or internal tag. Use a counting tool such as grep -c "<Tag>" TagManagement.xml in PowerShell or Linux.
4. Sum the occurrences of the <Tag> element. The breakdown between internal and external tags is preserved by the type attribute of the <Tag> element (e.g. type="external" vs type="internal"). Only the external count is relevant for Power Tag licensing.

4.2 Limitations of the file-inspection method

• The WinCC V7 project must be closed cleanly. A crashed Runtime can leave the project in a partial-consistency state where the XML export is incomplete.
• Project duplication or renaming does not affect the Power Tag count — the count is stored in the project file, not the license.
• Some legacy WinCC V6 projects migrated to V7 embed the original V6 structure; in that case the XML <Tag> count can be cross-checked against the count shown in the WinCC Explorer status bar once the project is open.

5. Reading the Tag Count in WinCC Runtime (When Project Is Already Running)

When a project's WinCC Runtime is already active on a server, the deployed tag count can be read through the WinCC diagnostics channel without opening the configuration. Two reliable methods exist:

5.1 WinCC Tag Management Runtime dialog

On the running server, open the WinCC Explorer (locally, RDP, or via the SIMATIC WinCC — WebNavigator remote tools) and inspect the same status bar as in the configuration environment. The Runtime license dialog does not change the live tag count; it only checks it.

5.2 SQL archive of the tag database

Every WinCC V7 Runtime server writes a CC_TagManagement_<computername>.RT file in the project directory. This file lists the live external tag set, including the connection name and data type. Open the file in a text editor or import it into a spreadsheet — the number of rows in the TagID column is the live external tag count. This is the same number that the license enforcement reads at Runtime startup.

6. Power Tag License Tiers — Sizing Logic

When the project's external tag count is known, select the smallest license tier that meets or exceeds the count. The table below maps a measured count to the smallest sufficient license.

Two Power Tag licenses installed on the same machine do not add up. WinCC V7 enforces a single license key per server; ordering two 1024-tag licenses does not yield 2048. Engineers must order the upgrade license that raises the existing key to the next tier, or the full target-tier license if no base exists. The Powertag Upgrade article numbers are listed in the Siemens Industry Mall under the same product tree.

7. Detecting an Undersized License Before Runtime Start

Before launching Runtime, the engineer can preempt the demo-mode dialog by inspecting the installed license key against the project's required count. Three checks are recommended in sequence:

1. Read the installed license — open the Automation License Manager (Start > Siemens Automation > Automation License Manager). Locate the WinCC V7 license key on the local machine and on the license server. The license manager shows the licensed Power Tag count as a property of the key.
2. Read the project's required count — open the project in WinCC Explorer (single-click Tag Management) and read the status bar as in section 3.
3. Compare — if the project count exceeds the licensed count by any amount, Runtime will start in demo mode and emit the 10-minute re-acknowledgment dialog until a Power Tag upgrade is installed.

8. Edge Cases and Field Notes

8.1 AS-OS engineering redirection

When a WinCC project references tags through a SIMATIC S7 connection that is itself attached to an AS-OS engineering redirection, the external tag count in the project file is the same as the deployed Runtime count, but the on-the-wire tag set may be smaller. The license is enforced against the project count, not the on-the-wire count.

8.2 Structured tags and UDTs

Each member of a structured tag (S7 user-defined type, WinCC structure tag) counts as one Power Tag. A single structure with 12 members uses 12 license units. This is a common source of surprise when a project crosses a 1024-tag boundary because of one large UDT.

8.3 Archive tags vs. process tags

Archive tags (variables logged to the SQL archive) are also external Power Tags if they map to a process connection. Calculated archive tags that are derived from already-licensed process tags do not consume an additional Power Tag, but they do count in the WinCC Explorer status bar as internal tags. The license check excludes them.

8.4 Redundant WinCC servers

Each WinCC server in a redundant pair requires its own Power Tag license of the same tier. A 4096-tag project running on a redundant pair requires 4096 Power Tags on the master and 4096 on the standby. The WinCC V7.3 manual describes the redundancy license structure separately from the Power Tag license.

8.5 WinCC Comfort/Advanced on a TIA Portal project

Engineers migrating a TIA Portal project (WinCC Comfort, Advanced, or Professional) to WinCC V7 must re-author the external tag database. The TIA Portal does not share the Power Tag count with V7 because the two product families use different license keys. Section 3's status bar method still applies, but the TIA project must first be compiled and exported to V7 before the count is visible.

9. Verification Procedure After License Upgrade

After installing the new Power Tag license, verify the upgrade in this order:

1. Open Automation License Manager and confirm that the new key is present and undocked (license key fully transferred from the USB stick to the local hard drive, or the network license is reachable from the license server).
2. Open the WinCC project in WinCC Explorer. The status bar at the bottom of Tag Management must show that the project's external tag count is less than or equal to the licensed count.
3. Start WinCC Runtime. The red "missing license" dialog must not appear. If it does, the license is either not activated, assigned to a different computer, or still on the original USB stick.
4. From the WinCC Explorer, open Help > About and confirm the licensed Power Tag count matches the purchased tier.
5. Verify alarm and archive subsystems are logging — the demo mode does not stop them, so they should be continuous across the upgrade.

10. Troubleshooting Matrix

11. Summary of Decision Flow

Use this flow when you inherit a WinCC V7 project of unknown size:

1. Install (or confirm) the WinCC V7 version that matches the project's .MCP file.
2. Open the project. If the local Power Tag license is below the project requirement, the project still loads in demo mode.
3. Single-click Tag Management in the Explorer tree; read the external tag count from the status bar.
4. If no WinCC installation of the matching version is available, rename the .MCP to .ZIP and count <Tag> elements with type="external" in TagManagement.xml.
5. Order the smallest Power Tag tier that meets the count, or the Powertag Upgrade to that tier from the Siemens Industry Mall.
6. Install the upgrade, verify with Automation License Manager, and re-test Runtime.

The single most important point: the project file itself, not the license, holds the tag count. Any WinCC installation of the correct version can read the count via the Tag Management status bar without modifying the project, regardless of how undersized the local license is. This makes tag-count discovery a 5-minute exercise before the license order is placed.

Frequently Asked Questions