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Configuration
7.3.3 RFB extension
In addition to transferring screen content, the RFB protocol (remote frame buffer protocol) is also used to transfer
data between a VNC client and the VNC server. This makes it possible to control VNC-based HMI applications.
These extensions can be configured in Automation Studio using library AsRfbExt.
Library AsRfbExt provides additional options for controlling VNC-based HMI applications and evaluating any input
devices connected to the client (B&R device). B&R's VNC Viewer must be used on the client with the RFB extension
enabled.
RFB extensions offer the following basic functions:
• Evaluating additional control devices on the Power Panel.
• Querying the temperature of the VNC client.
• Starting a process on the VNC client to carry out certain functions.
• Determining and limiting the number of connected VNC clients.
• Disconnecting VNC clients from the VNC server (Power Panel is not turned off, configurations remain).
• Reading the controller's operating hours.
Information:
For more information about RFB extensions and programming with library AsRfbExt, see the docu-
mentation in Automation Help.
Information:
Only one Power Panel with enabled RFB extension can be operated per B&R VNC server.
The following functions are described in this section:
•
Temperature monitoring
•
Adjusting display brightness
•
Outputting an audio signal
7.3.3.1 Temperature monitoring
Use case
Under certain circumstances (e.g. if the device is operated near the maximum permissible ambient temperature),
it makes sense for the application to monitor the temperature of the CPU component housing. The application can
take appropriate measures if a certain temperature is exceeded.
Notice!
The temperature of the CPU housing is not permitted to exceed 105°C. The service life of the processor
may be reduced at continuously high temperatures.
7.3.3.2 Adjusting display brightness
Necessary function of library AsRfbExt: RfbExtStartProcess()
Function RfbExtStartProcess() is used to adjust the display brightness process dim. Here, parameter pcmdLine is
used to call the command line process as follows:
Call syntax
dim brightness
Parameter
brightness ... Brightness of the display in percent [%]:
Example
pcmdLine: dim 75
The display brightness is set to 75%.
Implementation
In the VNC-based HMI application, a button is assigned a corresponding function that calls RfbExtStartProcess() with the correspond-
ing parameters. The application can take the display brightness from an input field that has also been defined in the HMI application.
The display brightness set with dim changes the current display setting but does not change the default setting
used after restarting the device.
The default display brightness setting is configured on service page Screen or in Automation Studio (see section
"Configuration" on page
In contrast to the setting option on service page Screen, dim can be used to set the entire brightness range of the
display from 0 to 100% (see
86
Valid range: 0 - 100
52).
"Service page Screen" on page
62).
Power Panel FT50 User's manual V1.19
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