WinCC Alarm Control: Animating Button Flash on Active Alarms

Overview

The Siemens WinCC Alarm Control displays process messages with state, priority, and acknowledgment columns. Operators frequently need an at-a-glance indicator outside the alarm window: a header button, a screen-level graphic, or a toolbar icon that flashes whenever at least one unacknowledged or active message exists. WinCC provides two complementary mechanisms to surface that information to a tag, and either mechanism can drive the native Flashing property of any graphic object:

1. Group Status Tag - a 32-bit DWORD inside AlarmLogging that encodes the current state of every message in a configured group or message class.
2. GMsgFunction() - a WinCC global C-script function called automatically on message events (come, go, acknowledge) that lets you write a custom tag or trigger an animation.

Both approaches are valid in SIMATIC WinCC V7.5 SP2 and later, as well as in WinCC Professional (TIA Portal) V17 and newer. The configuration path differs in dialog labels, but the underlying tag, event, and animation model is identical.

Prerequisites

• WinCC Explorer project loaded in WinCC V7.x or TIA Portal with a WinCC Professional runtime.
• An Alarm Logging editor with at least one configured message class (e.g., Error, Warning) and at least one single message or limit-value message.
• A button or graphic object on a process picture where flashing should occur.
• An internal tag of type WORD or BOOL created in the tag management to drive the animation.
• For VBS: Microsoft VBScript runtime registered with WinCC (default installation).

Method 1 - Group Status Tag (Recommended for Simple Cases)

The Group feature in Alarm Logging exposes a packed status DWORD that summarizes all messages belonging to the group. WinCC evaluates the DWORD on every message state change, so the value is always live.

Status Tag Bit Layout

If you only need a single boolean that is 1 whenever any active or unacknowledged message exists, evaluate bit 0, or test the DWORD against zero.

Configuration Steps

1. In the WinCC Explorer tree open Alarm Logging.
2. Right-click the Message Classes node (or any user-defined group) and select Properties.
3. Switch to the Group Messages tab.
4. Click Add to create a new group (for example GRP_ProcessErrors).
5. Check Status Tag and select an existing internal tag, or create one named Tag_AlarmStatus of type DWORD.
6. Click OK and assign every single message that should drive the indicator to the group. This can be done per-message on the Properties > Groups tab, or in bulk using the message class assignment editor.
7. Compile Alarm Logging (File > Compile or F7).

Wiring the Tag to the Button Flash

1. Open the process picture containing the button in Graphics Designer.
2. Select the button object and open Properties > Miscellaneous.
3. Set Flashing to Yes.
4. Open the Flashing Background dynamic dialog and bind it to a tag trigger.
5. Select the property Background Flashing On (or Flashing State) and configure a C-action or direct tag link:
   BOOL bFlash = (GetTagDWord("Tag_AlarmStatus") > 0); return bFlash;
6. Configure Flash Frequency to a comfortable rate, typically 500 ms on / 500 ms off for operator-attention level alarms.

Method 2 - GMsgFunction() for Custom Logic

When the group-status semantics do not match your use case - for instance, you need to fire only on messages from a specific source, area, or priority - use GMsgFunction(). This is a C-script callback invoked by the WinCC message system on every state transition. The signature is:

Parameter Reference

dwMsgState Bit Definitions

Sample GMsgFunction Implementation

// GMsgFunction.c - placed under "Standard Functions" in C-Editor
#include "apdefap.h"

void GMsgFunction(DWORD dwMsgServiceID, DWORD dwMsgID, DWORD dwMsgState,
                  DWORD dwMsgNr, char* lpszMsgText, char* lpszMsgName)
{
    static DWORD s_dwActiveCount = 0;

    // Came-in transition: increment counter
    if (dwMsgState & MSG_STATE_CAME_IN)
    {
        s_dwActiveCount++;
    }
    // Going-out transition: decrement counter
    if (dwMsgState & MSG_STATE_GOING)
    {
        if (s_dwActiveCount > 0) s_dwActiveCount--;
    }
    // Optional: skip process-acknowledged messages
    if (dwMsgState & MSG_STATE_PROCESS) return;

    // Drive an internal tag that the button flash listens to
    SetTagDWord("Tag_AlarmFlash", s_dwActiveCount);

    // Direct boolean for simple blink
    SetTagBit("Tag_AlarmFlashBit", (s_dwActiveCount > 0));

    // Suppress unused-parameter warnings
    (void)dwMsgServiceID;
    (void)dwMsgID;
    (void)dwMsgNr;
    (void)lpszMsgText;
    (void)lpszMsgName;
}

Method 3 - VBScript Approach (WinCC Professional / TIA Portal)

In WinCC Professional (TIA Portal), the C-script language is replaced by VBScript. The same effect is achieved by attaching a VB action to a tag trigger in Alarm Logging:

1. In the TIA Portal project tree, open HMI Tags and create an internal tag Alarm_Flash of type Bool.
2. In the alarm editor, open Settings > Acknowledgement concept and ensure Single acknowledgment is selected (or the variant matching your process).
3. Open the message class or message itself and switch to the Events tab.
4. Add a VB action on the Come event:
   SmartTags("Alarm_Flash") = True
5. Add a VB action on the Go event:
   SmartTags("Alarm_Flash") = False
6. Bind the button's Flashing property to Alarm_Flash.

For an aggregated count (more than one active message) use a global VBScript module:

' Module: AlarmAggregator
Dim gActiveCount : gActiveCount = 0

Sub OnAlarmCome()
    gActiveCount = gActiveCount + 1
    SmartTags("Alarm_Count") = gActiveCount
    SmartTags("Alarm_Flash") = True
End Sub

Sub OnAlarmGo()
    If gActiveCount > 0 Then gActiveCount = gActiveCount - 1
    SmartTags("Alarm_Count") = gActiveCount
    If gActiveCount = 0 Then SmartTags("Alarm_Flash") = False
End Sub

Button Flashing Property Configuration

The button object on the process picture is configured identically for all three methods. The flashing visualization in WinCC uses two on/off periods and an optional alternating background color.

Verification Procedure

1. Open WinCC Runtime in simulation mode (Start > Runtime or F5 in Graphics Designer).
2. Trigger a configured alarm using the alarm control's right-click Acknowledge simulation or by forcing the underlying PLC tag in PLCSIM / S7-PLCSIM.
3. Confirm visually that the button starts flashing within one update cycle (default 250 ms).
4. Acknowledge the alarm in the Alarm Control and verify that the button continues to flash if you bound the trigger to any active message, or stops flashing if you bound it to unacknowledged active messages only.
5. Reset the alarm source and confirm the flash terminates.
6. Inspect the tag value with the WinCC Tag Simulator or with GetTagDWord() in a test script to confirm numeric values match expectations.

Troubleshooting Matrix

Edge Cases and Field-Notes

• Single-message group: If the group contains exactly one message, the Status Tag behaves like a 1-of-N indicator. This is the simplest deployment for a "button blinks when there is any problem" requirement.
• Acknowledge semantics: WinCC distinguishes operator acknowledgment (clears the HMI flag) from process acknowledgment (PLC-driven). Bind to operator acknowledge if the operator is the source of truth; bind to process acknowledge if the PLC must confirm.
• Redundancy: On a redundant WinCC pair, the Group Status Tag is replicated by the internal alarm logging redundancy. No additional configuration is required for the flashing tag.
• Performance: GMsgFunction is called on every state change for every configured message. Keep its body under a few hundred microseconds; avoid logging or I/O inside the callback.
• Tag licensing: Internal tags do not consume WinCC power tags. Group Status Tags also do not consume power tags. Only PLC-bound tags count toward the tag license.
• Cross-picture use: An internal tag defined once in the tag management can be referenced from any number of pictures. A single Group Status Tag can therefore drive flashing indicators on every screen.
• WebNavigator / WinCC Unified: In WinCC Unified V17, the equivalent of GMsgFunction is a JavaScript function bound to the alarm control's Events configuration. The same Status Tag mechanism is supported but is configured under Alarms > Alarm groups in the Unified Comfort Panel editor.

FAQ