Resolving Disabled and Greyed Out 'ES Variables' in WinCC Tag Browser Across Multiprojects in PCS 7 V7.1

In SIMATIC PCS 7 (such as V7.1 SP2), when engineering graphic screens in WinCC Graphics Designer and finding that the 'ES Variables' (Engineering System Variables) tab in the WinCC Tag Selection dialog displays specific sub-projects as disabled, greyed out, or unselectable while other projects in the Multiproject function normally, the root cause is broken cross-project Plant Hierarchy synchronization, unmerged Industrial Ethernet subnets in NetPro, or missing Step 7 project database share permissions. When an OS Server project cannot validate the cross-project connection path to a specific AS sub-project through the merged plant bus, SIMATIC Manager suppresses that controller's CFC and SFC tag containers from the ES variable browser. To resolve this, engineers must merge subnets in NetPro, synchronize the Plant Hierarchy across the Multiproject, and re-export the OS connection data.

Architecture of the WinCC ES Variable Browser in SIMATIC PCS 7

In standard WinCC SCADA engineering, graphics designers browse only the local WinCC Tag Management database (WinCC Tags). However, in SIMATIC PCS 7, the Graphics Designer integrates deeply with the Step 7 database via the ES Variables tab.

The ES Variables tab allows engineers to browse directly into the Step 7 offline project: navigating the Plant Hierarchy, opening CFC charts, and interconnecting graphic object dynamics (e.g., color changes, bar graphs) directly to block pins possessing the S7_m_c := true attribute. This establishes automatic tag binding during subsequent OS compilations.

Root Cause Analysis: Why Specific Sub-Projects Appear Disabled

When browsing ES Variables displays some automation stations normally while two specific sub-projects appear greyed out with padlock or disabled icons:

Unmerged Subnets in NetPro: If the Plant Bus subnet in the affected AS projects has not been formally merged with the Plant Bus subnet in the OS Server project via NetPro's 'Cross-Project Subnets' manager, Step 7 considers the stations to be on electrically isolated networks. The tag browser blocks cross-network variable binding.
Plant Hierarchy Desynchronization: If the Plant Hierarchy (PH) folders in the affected sub-projects have different hierarchy depth settings or duplicate folder names, the global hierarchy tree breaks, disabling navigation into those sub-projects.
Exclusive Database Lock (.lck): If an AS project was opened over a network share by another engineering session or terminated abruptly, lingering Step 7 lock files (*.lck, *.tmp) block read access by the WinCC tag browser.
Missing AS-OS Assignment: In SIMATIC Manager, the S7 program container in the affected project must be assigned to the target OS in object properties.

The Role of Cross-Project Subnet Merging in NetPro

In a SIMATIC PCS 7 Multiproject, every single project contains its own local network definition. For ES Variables to resolve across projects:

Open NetPro at the Multiproject level.
Select menu Options > Multiproject > Cross-Project Subnets.
Verify that the Industrial Ethernet subnets of all AS stations and the CP 1623 card of the OS Server are merged into a single global subnet (e.g., Plant_Bus).
If an AS project's subnet is listed under 'Unassigned', select it and click Merge.

Step-by-Step Procedure to Re-enable ES Variables

To restore full accessibility to all sub-project variables in the WinCC tag browser:

Close All Editors: Close WinCC Explorer, Graphics Designer, and all CFC charts.
Synchronize Plant Hierarchy:
- In SIMATIC Manager, select the top Multiproject node.
- Select Options > Plant Hierarchy > Update in Multiproject.
- Confirm that the hierarchy levels and folder structures harmonize cleanly.
Merge Subnets in NetPro:
- Open NetPro from SIMATIC Manager.
- Merge all Plant Bus subnets across all sub-projects. Save and compile network configurations (Network > Save and Compile).
Reassign OS Target:
- In Component View, right-click the S7 Program folder of the affected AS stations and select Object Properties.
- Under the 'Operator Station' assignment tab, verify that the target OS Server is selected.
Execute Delta OS Compile: Right-click the OS Server, select Compile, and compile changes.
Reopen WinCC Graphics Designer; open the dynamic dialog on a graphic object and verify that the ES Variables tab enables full browsing into all sub-projects.

Comparison of WinCC Tag Selection Sources (ES Variables vs WinCC Tags)

The following table compares the two primary tag browsing mechanisms in PCS 7 WinCC Graphics Designer:

Browsing ModeData SourceProject ScopeTiming in WorkflowAutomated Tag GenerationES Variables TabStep 7 Project Database (.s7p)Multiproject-wide across all AS stationsPre-compilation (During display design)Automatically creates WinCC tags upon compileWinCC Tags TabLocal WinCC SQL Database (.mcp)Local OS Server onlyPost-compilation (Tags must already exist)Requires prior AS-OS compilationPicture Tree BrowserWinCC Picture HierarchyLocal OS Server graphicsPost-OS compilationBinds faceplates to plant hierarchyInternal TagsWinCC Local MemorySingle WinCC StationStandalone script designManual tag creation

Verification

Verify ES Variables accessibility in Graphics Designer:
1. In WinCC Explorer, open Graphics Designer and open any process screen (.pdl).
2. Insert an I/O Field; open the dynamic configuration dialog.
3. Select the ES Variables tab; expand the Multiproject tree.
4. Verify that all sub-projects display normal, active folder icons without grey shading or lock symbols.
5. Navigate into the previously disabled sub-projects; expand an AS CFC chart, select an analog block output (.PV_Out#Value), and click OK.
6. Confirm that the tag path binds cleanly into the graphic object.

Limitations and Operational Precautions

Never attempt to manually edit the internal Step 7 database files inside an S7 project folder using third-party database tools to 'force' variable access; doing so causes irreparable database corruption. In large multi-user engineering environments, ensure that all engineering clients map project network drives to identical drive letters (e.g., Z:\PCS7_Projects), as hard-coded UNC path variations between workstations can cause ES variable resolution to fail on specific seats.

Engineer FAQ

Why are ES Variables greyed out for some projects but not others?

Because the greyed-out sub-projects have unmerged subnets in NetPro, desynchronized Plant Hierarchies, or unassigned OS target associations, preventing Step 7 from establishing cross-project communication paths.

Can I still animate graphics if ES Variables are disabled?

Yes, by browsing via the 'WinCC Tags' tab, provided that the OS has already been compiled and the tags exist in the WinCC Tag Management database.

What does 'Update in Multiproject' do for the Plant Hierarchy?

It propagates the master Plant Hierarchy folder structure and level settings across all sub-projects, ensuring consistent naming and depth throughout the entire plant model.