Configuring Static Text Values in WinCC Unified Faceplate

Problem Overview: Static Strings at Faceplate Interfaces

Engineers building modular HMI screens in TIA Portal V17, V18, V19, or V20 with WinCC Unified routinely hit a wall when designing faceplates for repeated equipment (pumps, valves, motors, conveyors). The equipment label is unique per instance, but the value is constant for the life of the screen, so creating a per-instance HMI tag for the name is wasteful and bloats the tag list.

In WinCC Professional (TIA V16 / V17 / Classic) the workaround was trivial: bind a Symbolic I/O field to a faceplate interface property and supply a static text constant at instance creation. In WinCC Unified the same workflow silently fails: the configured static value is ignored in Runtime and the field shows the last cached value or an empty string. This article documents the root cause, the supported TIA V17→V20 methods, and the verification procedure that confirms a correct binding.

Root Cause: Interface Data Type and Dynamization Scope

Faceplate interfaces in WinCC Unified are strongly typed. The dynamization rules for the three property types differ at the RT engine level:

The original poster's WString-typed property is the problem. The TIA Portal faceplate editor accepts a static value for any text-typed property at configuration time, but the Unified RT engine only respects static values for the Multilingual Text data type. A plain WString property always resolves to its default initialization, the empty string, or the value of a bound HMI tag — never the static constant configured in the Inspector window. The discrepancy is documented in the Siemens Unified manual at Dynamizing an object property using a tag parameter (RT Unified), which restricts tag-parameter dynamization to faceplate instance interfaces and explicitly excludes static text for legacy string types.

Prerequisites

1. TIA Portal V17 Update 4, V18, V19, or V20 with WinCC Unified installed and licensed.
2. Unified Runtime V17.4 / V18 / V19 / V20 on the target device (Unified PC, MTP2200, MTP1500, TP2200 Comfort Unified).
3. An existing faceplate type (created via WinCC Unified > Faceplates in the project tree) with at least one interface property.
4. One or more faceplate instances placed on a process screen.
5. If you use the Script route, knowledge of JavaScript and access to the Global Definitions area under Scripts in the HMI device.

Solution 1 — Multilingual Text Property (Recommended)

This is the cleanest method and the one endorsed in the Siemens Knowledge Base and the TIA Unified help portal.

Step 1 — Modify the Faceplate Type

1. In the project tree, expand HMI device > Faceplates and double-click the faceplate type you want to edit.
2. In the faceplate editor, click an empty area to select the type, then open the Properties > Interfaces inspector pane.
3. Add a new property. Name it EquipmentName (case sensitive).
4. Set the data type to WString [Multilingual Text] — the [Multilingual Text] suffix is the critical selector. Plain WString will not work.
5. Save the faceplate type.

Step 2 — Bind the Property to a Screen Object

1. Inside the faceplate, drag a Text box (or Symbolic I/O field) onto the work area.
2. Open the text box Properties > General > Text.
3. Click the dynamization wand (lightning-bolt icon) next to the Text field and choose Faceplate property.
4. Select the EquipmentName property from the dropdown. The text box now displays the multilingual-text property value.

Step 3 — Provide a Static Value at Each Instance

1. Switch to the process screen containing the faceplate instance (e.g., Screen_Overview).
2. Click the faceplate instance once to select it.
3. In Properties > Interface > Properties, locate the EquipmentName row.
4. Click the value cell. The cell shows a small flag icon and accepts text in the project's active editing language. Enter, for example, P-101A.
5. To add translations, click the flag icon and add entries in every configured runtime language (English, German, Spanish, etc.).
6. Compile the HMI and download to the target device.

Solution 2 — Global Text List with a Numeric ID Property

When the same faceplate must display a name that is reused, localized, or already centralized, a Global Text List accessed by an Int property is more efficient than multilingual text and scales to thousands of equipment tags without inflating the project tree.

Step 1 — Create a Global Text List

1. Right-click HMI device > Text and graphic lists > Text lists and choose Add new text list.
2. Name it, for example, EquipmentNames.
3. Configure the list entries. For each row set the Default value (1, 2, 3, …) and the text in each language.

Step 2 — Reference the Global List from the Faceplate

1. In the faceplate, drop a Symbolic I/O field and set its Mode to Output (text list).
2. Open Properties > General > Configuration. The Text list field offers a scope selector — pick Global text list and select EquipmentNames.
3. Dynamize the Value property of the symbolic I/O field with a faceplate property of type Int named, for example, EquipmentID.

Step 3 — Supply the ID per Instance

1. On the process screen, click each faceplate instance and assign its EquipmentID property the integer that matches the row in EquipmentNames.
2. Runtime resolves the integer through the global list, so the same name appears in every language, governed by one central source of truth.

Solution 3 — Script-Assigned String

For dynamic names that originate from the PLC or a database (e.g., a recipe header or alarm descriptor), a script assigned to a faceplate property avoids creating a new internal tag.

Implementation Pattern

1. Add a faceplate property of type WString named ScriptName.
2. Bind a screen object's Loaded event to a JavaScript function:

// Global function or faceplate script
export function SetName(faceplate, plcbBuffer) {
  let s = Tags("PLC_DB_NameBuffer").Read();
  faceplate.Properties.ScriptName = s;
}

3. Bind the text box Text property to ScriptName.
4. Compile and download. The script writes the WString property at load, and the bound text field renders the value for the lifetime of the instance.

Comparison of Methods

Verification Procedure

After configuration, follow this sequence to confirm the static value actually renders in Runtime. A failed verification usually means the property type is still plain WString, or the screen object is not properly dynamized to the faceplate property.

1. Compile check: In TIA Portal choose HMI device > Compile > Software (rebuild all). The build must complete without warnings flagged under Faceplates. Warnings of the form Property 'EquipmentName' has no valid value indicate the multilingual text entry is empty in the active language.
2. Download and start Runtime on the Unified device. Switch the runtime language to verify each localized entry.
3. Instance inspection: In Runtime, click the faceplate instance. The instance name and the configured EquipmentName should both appear in the Faceplate Instance dialog (opened with the chevron or the configured open-popup event).
4. Tag monitor: Open HMI Tags > Diagnostics in the running RT (or use the WinCC Unified Tag Simulator in TIA) and confirm that no new HMI tag was generated for the static name.
5. Cross-screen test: Place two instances of the faceplate on a second screen and assign them different EquipmentName values. Runtime must render them independently — a cross-over indicates a broken property type that is being globally initialized.

Troubleshooting Matrix

Performance and Tag-List Considerations

A typical pumping station with 80 valves, 40 pumps, 20 fans, and 60 motors contains 200 equipment tags. Using the old pattern of a per-instance HMI tag, that adds 200 WString entries to the project tag list — each one counting against the licensing threshold for WinCC Unified tags. Switching to the Multilingual Text faceplate property eliminates all 200 tags. For installations licensed by tag count, the savings are direct: 200 × the per-tag license cost is recovered by re-architecting the faceplate.

For high-density screens (more than 50 faceplate instances on a single screen), the Multilingual Text route outperforms the text-list route on initial paint because the string is pre-resolved at the screen load event, whereas the text list requires an indirection through the global list during the first cycle. On a Unified Comfort Panel with the MTP2200, this can amount to 80–120 ms of additional screen-load latency at 50 instances; on a Unified PC the difference is negligible.

Migration Notes for Existing V17 Projects

If a project was built with the legacy pattern (plain WString property + per-instance HMI tag), migrate in three passes:

1. Type change: Open every faceplate type and convert text-typed properties used for static names to WString [Multilingual Text].
2. Reference reroute: On every screen, remove the per-instance HMI tag and replace it with the static value configured in the property cell of the faceplate instance.
3. Tag cleanup: After successful Runtime verification, delete the now-unused HMI tags in batch using the project tree. TIA Portal offers no rollback — back up the project before batch delete.

Best Practices Checklist

• Reserve WString [Multilingual Text] for human-readable labels and descriptions only. Do not use it for process data, setpoints, or any value that the PLC needs to see.
• Use a numeric Int faceplate property and a global text list whenever the same set of names must be referenced by more than one faceplate type.
• Keep faceplate property names lowercase with camelCase suffix for unit (Pump101.pressureUnit) — Siemens' own example libraries follow this convention.
• Document each faceplate type's interface in the project notes; a multilingual property with no fallback in the active language renders as blank without a warning.
• Lock the faceplate type after commissioning to prevent accidental interface changes — a changed property type breaks every existing instance in the project without warning at the property-cell level.

FAQ