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Custom Web Control
About Screen Region Capture
Screen Region Capture is a Custom Web Control for SCADA and HMI screens that saves its own screen area as a JPG image file. The control is fully transparent, so it can be placed over any part of a process graphic, trend or mimic to capture exactly that region. Captures can be triggered by a PLC-driven tag or from a script, which makes it practical for documenting alarms, batch steps and operator actions.
Key Features
- Tag-driven capture: A rising edge (false to true) on captureTrigger saves one image while the control is enabled.
- On-demand capture: The requestCapture() method triggers a capture of the control area at any time.
- Capture notification: The CaptureRequested event returns the control width and height in pixels and the full JPG file path.
- Transparent overlay: The control has no visual footprint, so it does not change the existing screen layout.
Customization
All behaviour is set through four contract properties, configured in the engineering tool and bindable to HMI tags:
- targetDirectory: Folder where the captured image files are saved.
- fileName: Base name of the capture file; the .jpg extension is added automatically.
- enabled: Turns capturing on or off. When false, no capture is triggered.
- captureTrigger: Boolean tag that starts one capture on each rising edge.
Use Cases
Typical applications include recording alarm screens at the moment of occurrence, documenting process states for quality audits, archiving batch recipe screens, and supporting operator shift reports in control rooms.
Compatibility
Designed for WinCC Unified and WinCC V8. Import the Custom Web Control into your TIA Portal project and link its properties to HMI tags. Tags linked to properties that the control must write to should not be set as read only in TIA Portal; otherwise the control can only read them.
AI-Generated: This Custom Web Control was generated using artificial intelligence. Test and validate it thoroughly before deploying in production environments.
⚠️ AI-Generated: This custom web control was automatically generated using AI technology. It may contain errors or unexpected behavior. Users are responsible for testing and validating before using in production environments.