Configuring WinCC Alarm Windows in TIA Portal Global Screen

When a TIA Portal HMI project is generated by the HMI Wizard, WinCC automatically inserts two persistent Alarm Windows into the project's Global Screen: one for Pending alarms and one for Unacknowledged alarms. These windows appear as overlays on every screen in the runtime, regardless of which process picture is active. In most production HMI designs this behavior is undesirable because the operator does not need both summary views simultaneously, and the overlays interfere with the active faceplate.

This reference covers the architecture behind that design, the exact navigation path used to reach the Global Screen in both WinCC Comfort/Advanced and WinCC Unified (RT Unified), and the procedure to delete, replace, or recreate single-instance alarm controls. It also documents the relevant alarm-class settings in the Alarm view properties so that system diagnostic events can be displayed when required.

1. Background: Why Alarm Windows Live in the Global Screen

WinCC distinguishes between two presentation objects for alarms:

• Alarm view (Alarm Control) — a screen-bound WinCC control that is embedded in a single picture. It shows the alarm history or a filtered subset of the active message queue.
• Alarm Window — a global overlay that WinCC positions on top of the current screen automatically when new pending or unacknowledged messages are present. By design this overlay must be reachable from every picture, which is why the editor only allows it in the Global Screen layer.

The HMI Wizard inserts a default template containing both views during project creation so that the new project is "runtime-ready" out of the box. Once the engineer has a clear alarm philosophy (for example, "only the most recent unacknowledged alarm is visible"), the surplus windows must be removed manually because the wizard does not offer a configuration dialog to suppress them.

2. Alarm Classes and Message States

Before modifying the Global Screen, it is helpful to understand the alarm categories WinCC exposes, since these are what the Alarm Window filters on by default.

Each alarm traverses the following state machine:

1. Pending — the trigger condition is active; the alarm has not been acknowledged.
2. Unacknowledged — a previously pending alarm has cleared (gone inactive) without operator acknowledgement.
3. Acknowledged — the operator pressed the ACK key/button on a still-pending alarm.
4. Historical / Logged — the alarm moves into the archive once it has been acknowledged and the trigger is no longer active.

The two alarm windows the wizard generates filter the message queue by Pending and Unacknowledged state respectively. Both are usually rendered as pop-up overlays, which is why two popup layers are visible during commissioning.

3. Prerequisites

• TIA Portal V16 or later (V17 / V18 / V19 / V20 / V21 supported). For WinCC Unified V21 targets, use the matching TIA Portal version.
• WinCC Comfort, Advanced, or Professional for the Comfort/Advanced workflow described in section 4.
• For WinCC Unified targets, the Alarm control in the RT Unified toolbox is configured per the procedure in section 5.
• The HMI device must be the active editor target (click the HMI in the project tree so its configuration opens).

4. Step-by-Step: WinCC Comfort / Advanced — Modifying Alarm Windows

4.1 Open the Global Screen

1. In the TIA Portal project tree, expand the HMI device (for example, HMI_1 [KTP1200]).
2. Expand "Screens" under the device node.
3. Expand "Screen management".
4. Double-click "Global Screen".

The Global Screen editor opens. It is normally empty except for the wizard-generated alarm windows. Each Alarm Window is shown as a separate rectangular object, named (for example) Alarm Window_Pending and Alarm Window_Unacknowledged.

4.2 Delete an Unwanted Alarm Window

1. Click the Alarm Window you no longer need (Pending or Unacknowledged). The selection handles appear.
2. Press Delete, or right-click → Delete.
3. Confirm any "object in use" prompt. The window is removed from the Global Screen and will no longer be rendered at runtime.
4. Compile the HMI (right-click the HMI device → Compile → Software (rebuild all)) to ensure the change is propagated to the runtime files.

4.3 Re-create a Single Alarm Window with Custom Properties

If you want a single alarm window with custom filter settings (for example, "only show unacknowledged alarms with priority ≥ 12"), recreate it manually:

1. With the Global Screen editor open, drag "Alarm view" from the Tools pane (under Controls) onto the Global Screen canvas.
2. Resize and position the alarm view. Since this is the Global Screen, the position is interpreted as the screen-relative popup position.
3. In the Properties > General pane, set:
   • Display name: e.g. AlarmWindow_CriticalOnly
   • Alarm classes: Enable Errors only. Check the box to display Diagnosis events if system diagnostic alarms from the PLC are required (see Configuring Messages and Alarms in WinCC (TIA Portal)).
4. In Properties > Columns, enable the columns you need: Number, Time, Date, State, Text, Acknowledgement.
5. In Properties > Filter, define a SQL-style filter, e.g. "State = 1 OR State = 3" to display pending and acknowledged alarms.
6. Compile and download to the HMI panel.

4.4 Typical Filter Expressions

5. Step-by-Step: WinCC Unified (RT Unified) — Alarm Control Configuration

For Unified panels and PC Runtime, the equivalent of the classic Alarm Window is the Alarm control object in the RT Unified toolbox. The placement rules are identical (global objects live in the global layer), but the configuration dialog differs.

5.1 Insert the Alarm Control

1. Open the project tree → HMI device → Screens → open Global Screen (or your target screen).
2. From Toolbox > Controls, drag Alarm control onto the canvas.
3. Refer to Alarm control (RT Unified) — WinCC Unified for the full object reference.

5.2 Configure Source and Filter

1. In Properties > Alarm control > General, choose the alarm source: Alarm log (historical), Active alarms, or Logged alarms.
2. Under Filter, define:
   • Alarm class filter: tick Errors, Warnings, etc., as required.
   • State filter: select Pending, Unacknowledged, Acknowledged.
   • Priority range: e.g. 0–16.
3. Enable Single acknowledgment if your project uses the new V17+ ACK model.
4. Configure the toolbar and status bar visibility from Properties > Appearance.

5.3 Enable Diagnosis Events

To surface S7-1200 / S7-1500 system diagnostic alarms in the Unified alarm control:

1. Open the Alarm control properties.
2. Navigate to Properties > General > Alarm classes.
3. Enable the "Diagnosis events" checkbox as described in the Siemens PDF on Configuring Messages and Alarms.
4. Ensure the connected PLC has System diagnostics enabled in the device configuration.

6. Removing Wizard-Generated Alarm Windows at Source

If you want to suppress the wizard from generating the two default alarm windows at all, you must intercept them at creation time. TIA Portal does not provide a project-level toggle to disable the wizard template, so the supported approach is:

1. Create the HMI as normal.
2. Immediately navigate to the Global Screen (section 4.1).
3. Delete both alarm windows before adding any user content.
4. Save the project as a project template via Project > Save as project template for reuse.

This practice eliminates the need to delete them on every new HMI device you add to a template-driven architecture.

7. Verification

After deleting or reconfiguring the alarm windows, validate the change end-to-end:

1. Compile the HMI device. Watch for warnings of the form "Object 'AlarmWindow_Pending' is referenced but not found". If you see this, an animation or VB/C script elsewhere in the project still targets the deleted window. Either re-bind the script or remove the reference.
2. Download the project to the panel (or start the RT simulation via Start Runtime).
3. Trigger a known alarm from PLCSIM or from the connected PLC.
4. Verify only the intended alarm control is visible.
5. Press the ACK button on the panel and confirm the alarm transitions to the Acknowledged state.
6. Restart the runtime and confirm that no ghost alarm window appears as an overlay.

8. Troubleshooting Matrix

9. Common Engineering Pitfalls

• Treating Alarm Window as a screen-bound object. It is global by design; deleting it from any process picture has no effect because the runtime overlay is owned by the Global Screen layer.
• Forgetting the recompile. TIA Portal will silently retain the deleted alarm windows in the compiled runtime until the next full rebuild.
• Leaving the wizard template active. If you add a second HMI device of the same type to the project, the wizard will regenerate both alarm windows for that device. Always delete immediately after creation or work from a template.
• Confusing Pending with Unacknowledged filters. Pending = the trigger is currently active and not yet ACK'd. Unacknowledged = the trigger was active but cleared before the operator pressed ACK. Most plants only need Unacknowledged in a popup overlay; Pending is usually displayed on a permanent faceplate.

10. Quick Reference: Navigation Path