Resolving WinCC Professional V14 SP1 Bar Graph Runtime Visibility

Problem Summary

A bar graph inserted from the WinCC Professional V14 SP1 toolbox renders correctly at design time but becomes invisible in runtime once a real-typed process tag is bound to its value property. The defect reproduces on both the WinCC RT simulator and the physical HMI panel (Comfort Panel, TP/Comfort Unified, or PC-based runtime), regardless of whether the source PLC is an S7-1200, S7-1500, ET 200SP, or S7-300/400 connected via PROFINET or PROFIBUS. The same screen displays no bar fill, no scale labels, and no border even though the underlying tag polls without error in the HMI tag diagnostics view. Re-dragging the bar from the library restores visibility until the process tag is wired, indicating the issue is triggered by tag binding rather than by the screen object itself.

This defect is documented as resolved in the official TIA Portal V14 SP1 Update 2 release notes under the heading "Screens and screen objects." Engineers encountering the symptom in V14 SP1 GA (without Update 1 or later) must install Update 2 (or the cumulative Update 3) to restore bar, slider, and pointer-instrument rendering against multiplex and process tags.

Affected Software Versions

Root Cause Analysis

The defect originates in the WinCC Professional V14 SP1 screen-object rendering pipeline. When a process tag of elementary type Real is connected to a bar, slider, or pointer instrument, the property update path that propagates the configured maximum, minimum, and current value fails to commit the visibility flag of the bar's drawing layer. The bar's geometry, color ramp, and tick-mark arrays are pushed to the runtime buffer, but the layer's Visible attribute remains in the design-time state of False, producing an empty screen region.

Two related defects are corrected simultaneously by Update 2:

1. Multiplex tag binding: Bar, slider, and pointer instruments could not consume a multiplex tag index without corrupting the screen object's drawing context. Multiplex tags allow a single visual element to mirror different PLC values based on the current index, eliminating duplicate bar widgets per measured point. Prior to Update 2, the multiplex indirection caused the same invisibility condition.
2. Animation propagation: When a configured tag was modified in any of the dynamic interfaces (appearance, position, color) of a selected screen object, the change failed to broadcast to sibling objects in the same selection set. The engineer could not batch-update bars sharing a common PLC tag structure.

Both issues are addressed by V14 SP1 Update 2 and inherited by all subsequent updates through V14 SP1 Update 7. The official Siemens readme states verbatim:

"Screens and screen objects
Multiplex tags can be used in bars, sliders and pointer instruments.
A change to the configured tags in an animation affects all of the selected objects."

Solution: Install TIA Portal V14 SP1 Update 2 or Later

Prerequisites

• Local administrator rights on the engineering workstation.
• All TIA Portal instances closed before patch deployment.
• Siemens Automation License Manager installed and functional.
• A valid TIA Portal license (floating or single-user) for at least one WinCC Professional editor seat.
• Minimum 4 GB free disk space on the system partition for the patch expansion.
• Project archive (.zap14) committed to source control or external backup prior to upgrade.

Step-by-Step Update Procedure

1. Navigate to the official Siemens Industry Online Support portal and locate the entry for SIMATIC TIA Portal V14 SP1 Update 2 (article ID 109749283 or the equivalent delivery record for cumulative Update 3).
2. Download the package SIMATIC_TIA_Portal_V14_SP1_UPD2.exe (or the corresponding cumulative installer) to a local working directory.
3. Right-click the installer and execute Run as administrator. The setup detects the existing V14 SP1 base installation and prompts for upgrade mode.
4. Accept the license agreement and confirm the target installation path matches the existing TIA Portal root (default C:\Program Files\Siemens\Automation\Portal V14 SP1).
5. Select Complete component coverage to ensure WinCC Professional, WinCC Runtime Professional, PLCSim, and all HMI device packages receive the patch.
6. Allow the installer to stop the TIA Portal background services (TIA Administrator, ALM, license server) and complete file replacement. A typical upgrade requires 10-20 minutes.
7. Restart the engineering workstation when prompted to refresh the registry and service entries.
8. Verify the upgrade by launching TIA Portal, opening Help → Installed Software, and confirming the WinCC Professional version reads 14.0.1.2 or later.

Alternative: Cumulative Update 3 Deployment

Update 3 includes Update 1 and Update 2 plus additional corrections for the TIA Portal framework (graph editor, project library, multiuser server). Installing Update 3 is recommended when multiple patch levels are missing, as it consolidates the deployment into a single maintenance window. Cumulative installers follow the same procedure as Update 2; the executable name is SIMATIC_TIA_Portal_V14_SP1_UPD3.exe.

Verifying the Bar Graph Visibility Fix

After applying Update 2 (or later), perform the following regression test sequence to confirm the bar graph renders correctly in runtime:

1. Open the affected TIA Portal project and navigate to the HMI device containing the bar object.
2. Select the bar widget in the screen editor. Confirm the Properties → General → Process value field references the correct Real HMI tag.
3. Compile the HMI station: right-click the HMI device → Compile → Software (rebuild all). A clean compile emits no warnings or errors referencing the bar object.
4. Start the WinCC Runtime via Online → Start Runtime (simulator) or download the project to the panel.
5. Force the PLC tag to mid-range value (e.g., 50% of configured max) from the PLC's watch table or PLCSim.
6. Observe the bar fill: the colored fill region must extend from the configured minimum endpoint to the value marker. The scale, tick marks, and label must remain visible.
7. Force values at 0%, 25%, 75%, and 100% to validate linear interpolation and end-cap rendering.
8. Trigger a value change during runtime to confirm the bar updates in real-time without flicker, blanking, or screen refresh artifacts.

Configuring the Bar Object Correctly

Beyond the update installation, validate the bar configuration against the documented WinCC Professional schema:

Working with Multiplex Tags on Bars

The Update 2 fix enables multiplex tag indexing for bars, sliders, and pointer instruments. A multiplex tag is a structured HMI tag containing an array or UDT whose index is driven by a separate index tag. The bar then displays the value at the current index, eliminating the need for N bar widgets per N measured points.

Multiplex Tag Configuration Procedure

1. Define a UDT in the PLC (e.g., typeMeasurementPoint) with a Real value, Bool alarmHigh, and other fields.
2. Create an HMI tag of type WString or array Array[0..31] of Real matching the UDT structure.
3. Add a separate Int HMI tag named IndexVar to drive the multiplex selector.
4. Open the bar object's Properties → General. In the Process value field, click the tag selector and choose Multiplex tag.
5. Select the array tag and the index tag. Confirm the type matches the bar's value property (Real).
6. Compile and download. Increment IndexVar at runtime via a script or screen button to switch the displayed measurement point.

Animation Propagation Behavior

Prior to Update 2, modifying a tag reference in the animation interface (e.g., appearance color, position offset) of one screen object did not propagate to other selected objects sharing the same tag. Engineers working with grouped bars (e.g., a row of 8 bars representing motor currents) had to re-edit each object's animation individually.

Update 2 introduces selection-set animation broadcasting: with multiple screen objects selected, editing a dynamic tag in the animation panel applies the change to every selected object whose interface supports that animation type. This is a productivity fix rather than a runtime correctness fix, but it is the second half of the official Update 2 release note.

Recommended Workflow for Grouped Bars

1. Insert the first bar and fully configure it (process value, color, limits, scale).
2. Select the bar, copy with Ctrl+C, and paste it with Ctrl+V to clone the configuration.
3. Multi-select all cloned bars using Shift+Click or rubber-band selection.
4. Open the Animation panel. Modify the Appearance tag reference. The change applies to all selected bars in a single operation.
5. Repeat for Position and Color animation interfaces as required.

Project Migration Considerations

Projects created in V14 SP1 GA open without modification after Update 2 installation. The update is binary-compatible at the project file level. However, the following clean-up tasks are recommended to avoid downstream issues:

• Re-compile all HMI stations after the update installation. Compiled runtime files generated by GA versions may reference obsolete symbol IDs.
• Re-download panel images to physical Comfort and Unified Comfort panels. The runtime mirror stored in the panel flash retains pre-update binaries until overwritten.
• Validate scripts that reference bar objects by name. The screen-object internal naming scheme was not changed by Update 2, but downstream V15 migrations may require renaming.
• Audit library references for any custom master copies of the bar object. Custom bar variants may need to be re-anchored to the updated master.
• Back-archive the project as ProjectName_v14sp1_u2.zap14 to capture the post-update build for traceability.

Related Configuration: Process Tag vs. PLC Tag

The original symptom was triggered by binding a process tag of type Real. The distinction between HMI tags and direct PLC address references is critical in TIA Portal V14 SP1:

When the bar disappears after binding, verify the HMI tag exists in the HMI tag table, the connection path to the PLC is established (right-click HMI device → Connections), and the PLC tag is reachable. Use the HMI tag diagnostics view (Online → HMI tag diagnostics) to confirm the tag is updating.

Field Diagnostics Checklist

If the bar remains invisible after Update 2 installation and project recompile, execute the following diagnostic sequence:

1. Tag update rate: In Online &ranti HMI tag diagnostics, force the value and confirm the HMI tag updates within the configured acquisition cycle. A frozen tag indicates PLC connection issues, not bar object issues.
2. Range validity: Confirm the process value falls within the bar's configured [Min, Max] range. Values outside the range clamp but should still render; values returning NaN (e.g., from division by zero in the PLC) cause the bar to disappear.
3. Visibility animation: Open the bar's Properties → Animations panel. If a visibility animation is configured, inspect the trigger tag and Boolean expression. A False trigger tag hides the bar regardless of value binding.
4. Layer order: Check the screen layer ordering. A solid-fill rectangle or other object drawn above the bar layer occludes it. Move the bar to the topmost layer via Arrange → Bring to Front.
5. Screen resolution scaling: On high-DPI engineering workstations, the bar may render at 0 height if the screen zoom factor is non-integer. Reset the editor zoom to 100%.
6. Corrupted compilation: Delete the compiled HMI station files (project subdirectory \IM\HMI\<station>\Compile) and recompile from scratch.

Forward Path: WinCC Unified RT Bar Object

Engineers planning to migrate from WinCC Professional V14 SP1 to WinCC Unified (V17, V18, V19, V20) should review the unified bar object's property model. The unified bar inherits the corrected rendering pipeline from V14 SP1 Update 2 onward, eliminating the legacy visibility bug entirely. The configuration surface is exposed in the Inspector window under Layout, Appearance, and Animations categories, with the process value, minimum, maximum, and color ramp configurable from a single property sheet.

For projects targeting Unified Comfort Panels (MTP700 Unified, MTP1000 Unified, MTP1200 Unified, MTP1500 Unified, MTP1900 Unified, MTP2200 Unified), the bar object is native to the Unified runtime and does not require legacy WinCC Professional fix-ups. Migrate bar-heavy screens from V14 SP1 Comfort Panels to Unified Comfort Panels when panel hardware replacement is on the maintenance schedule.

References and Standards

Engineers verifying the fix should consult the official Siemens documentation:

• SIMATIC TIA Portal V14 SP1 Update 2 Readme (Siemens Support, ID 109749283)
• Bar (RT Unified) - WinCC Unified V20 Screen Objects Reference

Frequently Asked Questions