Configuring Trend Annotations and Event Markers in SIMATIC PCS 7 WinCC

Standard SIMATIC PCS 7 WinCC Online Trend Controls do not natively support interactive, free-text operator annotations directly attached to trend coordinates. To log and display operator annotations (such as process excursion root causes or sample collection times) on trend displays, deploy an integrated architecture: utilize WinCC User Archives or custom SQL tables to store timestamped operator comments, and position dynamic graphic markers on the trend window using VBScript coordinate scaling (modeled after the Siemens Condition Monitoring Library PumpMon block). Alternatively, synchronize the Trend Control with the WinCC Alarm Control ruler or deploy SIMATIC Information Server for enterprise annotations.

WinCC Online Trend Control Capabilities and Annotation Limitations

In SIMATIC PCS 7 OS (WinCC), the WinCC Online Trend Control (WinCC TrendControl) displays real-time and historical process data retrieved from Tag Logging. The control provides advanced analytical tools: statistical rulers, dual cursors, zoom functions, and high/low threshold reference bands.

However, industrial process operators frequently require the ability to click a trend curve, enter a comment (e.g., 'Manual sample taken - Viscosity 42 cP' or 'Feedstock valve hunting due to line pressure dip'), and have a persistent visual annotation flag or marker pinned to that exact time coordinate. Standard WinCC Trend Control does not have a native interactive annotation pin tool; engineers must implement standard architectural patterns to satisfy this requirement.

Architectural Solutions for Operator Annotations in WinCC

Three proven engineering approaches provide operator annotations in SIMATIC PCS 7:

User Archive Coordinate Marker Overlay: Operator comments and timestamps are stored in a WinCC User Archive (Annotations_UA). In Graphics Designer, a floating vector dot or flag icon sits on an overlay layer above the trend control. A VBScript scales the pixel position of the dot based on the trend's current X-axis time window and Y-axis scale (a methodology pioneered in the Siemens Condition Monitoring Library block PumpMon in @PG_PumpMon_NQCurve.pdl). Clicking the dot displays the stored comment in a popup.
Alarm Control Chronological Ruler Synchronization: Operators enter notes using standard WinCC Alarm Logging comment functions (Acknowledge with comment or Operator input message). By locking the time ruler of the Trend Control to the Alarm Control, operators correlate process spikes with logged operational comments.
SIMATIC Information Server / Process Historian: For long-term analytical reporting, Information Server provides native web-based trend annotation, enabling plant supervisors to attach comments directly to historical trend reports.

Comparison of Trend Annotation and Event Marking Methods

The table below contrasts engineering complexity, storage mechanisms, and operational feedback across annotation methods:

Annotation StrategyStorage MediumVisual Feedback on ScreenEngineering Complexity & LicensingUser Archive Marker OverlayWinCC User Archive (SQL)Coloured dots / flags on trend canvasModerate (VBScript coordinate calculation; requires User Archive license).Alarm Logging Note CorrelationWinCC Alarm DatabaseHighlighted message in synchronized listLow (Zero scripting; uses standard WinCC Alarm Control features).Custom APL Block (EventTS)S7 Controller / Tag LoggingDiscrete event marker line on trendLow (Consumes 1 PO; triggers high-precision SOE event tag).SIMATIC Information ServerProcess Historian SQLNative web report callout boxesEnterprise-grade (Full shift reporting with zero WinCC screen scripting).

Step-by-Step Implementation of User Archive Event Markers

Create Annotations User Archive:
- In WinCC Explorer, open User Administrator / User Archive.
- Create a table named TrendNotes: define fields TagID (String), EventTime (DateTime), NoteText (String), and MarkerColor (Integer).
Design Operator Input Dialog:
- In Graphics Designer, place an Add Note button adjacent to the Trend Control.
- On click, launch a modal dialog allowing operators to enter text and capture the current ruler timestamp (TrendControl.RulerTime).
- Execute an SQL insert or User Archive write script (uaArchiveInsert).
Implement Coordinate Marker Positioning Script:
- On the trend screen, insert a small circle graphic (MarkerDot).
- In the Trend Control OnRulerChange or screen refresh event, execute a VBScript to map EventTime to X-pixel offset:
vbscript ' Calculate relative position within visible trend window TimeSpan = TrendCtrl.TimeAxisTimeRange StartTime = TrendCtrl.TimeAxisBeginTime X_Pixel = TrendCtrl.Left + ((EventTime - StartTime) / TimeSpan) * TrendCtrl.Width MarkerDot.Left = X_Pixel
Bind Tooltip to Note Text: Bind the TooltipText property of MarkerDot to the NoteText field from the archive.

Verification

Verify annotation functionality through the following tests:
1. In WinCC Runtime, open the trend window: click the Add Note button and enter: 'Test Sample 01': confirm that record is written to the archive.
2. Confirm that a colored marker dot appears above the curve at the exact timestamp coordinate.
3. Hover the mouse over the marker: confirm that the tooltip displays 'Test Sample 01' and that zooming the trend causes the marker to scale synchronously.

Limitations and Operational Precautions

Avoid triggering complex SQL queries inside high-frequency screen trigger scripts ($< 1\text{ second}$). Heavy database polling on client workstations can cause Graphics Designer interface freezes. Trigger coordinate recalculations strictly on screen initialization, time range change, or when an operator adds a new note. For validated pharmaceutical installations, ensure annotations utilize SIMATIC Logon to record the author's electronic signature.