Server extension

The TwinCAT HMI NuGet package Beckhoff.TwinCAT.HMI.Vision contains the HMI server extension TcHmiVision, with which images from the PLC can be displayed in the TwinCAT HMI. For this purpose, all ADS symbols of the type ITcVnDisplayableImage from the configured runtimes are listed and can be linked in various formats with an HMI symbol. See System requirements for the required .NET version.

Configuration

Once the package has been successfully integrated into the HMI project, enter the target PLC under Server > TcHmiVision:

Application

1. Navigate to an HMI view and add an Image control.
Server extension 2:

2. Open the properties of the control element and click on Create data binding… under the parameter Src…
Server extension 3:

3. Link the Src parameter of the Image control to the corresponding image symbol at the following location: Server symbols > TcHmiVision > PLC > MAIN > ipImage > <image format>
Server extension 4:

	Linking images Linking images is only possible if the process image of the configured target system contains corresponding image variables.

	Interval The speed at which images can be retrieved from the PLC depends on the system, image size, and workload. We therefore recommend specifying a fixed interval in the Binding dialog at Settings to prevent the system from being overloaded. If several images are to be displayed on one page, it is also recommended to use different intervals, e.g. 200 ms and 201 ms. This way, the images are retrieved separately from each other, which can be advantageous for larger amounts of data.

Transmission formats

The server extension contains the image data from the PLC in BMP format and forwards them as a Base64 string to the TwinCAT HMI client. In order to reduce the data quantity transmitted to a client, images can be compressed in the server extension. The following image formats are available:

BMP: uncompressed
JPEG: lossy compressed, good for natural images
PNG: compressed (lossless), good for artificially created images
Stream: for continuous image streams (e.g. live camera picture, not recommended!)

	For transmission as a stream the HMI server must be started as administrator. Otherwise no image transmission is possible.