APC4100 with an AP240C CB DP | Display Port brightness control via software

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1

Hello everyone,

We have a customer using an APC4100 with an AP240C CB DP (DisplayPort Receiver) running Windows 11 2024.

Previously, they used an APC3100, SDL display receivers, and Windows 10 2021.

They develop maritime applications, so the hardware must be certified accordingly and mounted observing IP degree of protection.

With the SDL link, they were able to control the display brightness using a slider that was available both in the Windows taskbar and in their SCADA application. After upgrading to the APC4100 platform, they noticed that this brightness control is no longer available.

So far, the only method I have found in the documentation is to adjust the brightness through the display’s OSD menu. However, this requires pressing the button on the back of the Automation Panel, which is not practical for their application. The brightness needs to be adjusted frequently depending on ambient conditions such as daylight, nighttime operation and weather.

The customer has already:

  • Installed the ADI driver
  • Checked Windows 11 registry settings
  • Reviewed Windows Group Policy settings

Unfortunately, none of these actions resolved the issue.

While researching, I found references to DDC/CI (Display Data Channel / Command Interface). My understanding is that, when using a DisplayPort connection, the monitor/display receiver must support DDC/CI to allow software-based brightness control.

Please, is this correct?

Has anyone successfully implemented brightness control on an AP240C CB DP connected to an APC4100, or can suggest another approach?

System details

  • APC4100 B1 11865MRE 32 480T W11 ZA
  • AP240C CB DP (5AP933.240C-00 + 5DLDPO.1001-00)
  • Windows 11 2024 (5SWW11.0266-MUL)

Thanks in advance!

2

Hi,

I’m not aware if the DP receiver suppports the DP DDC Command Interface, from datasheet unfortunately it doesn’t looks like (the CI part of DDC/CI is not mandatory on a DP interface).
I would propose to ask via official support channel, if /CI is supported at the receiver (and additionally, if the PC graphic engine/chipset supports it).

When using SDL, the backlight control is communicated via the APC/PPC MTCX controller over a dedicated command Interface inside SDL. The software control on Windows then is done by the B&R ADI driver - I think this was the way how it worked with the former hardware setup (APC3100 + SDL reveiver), and would also work with APC4100 if using a SDL transmitter in the APC + SDL receiver instead of a DP receiver on display side.

Best regards!