ED-HMI Series Products Backlight Adjustment

1 Overview

Introduces the background and applicable scope of backlight adjustment for the ED-HMI series products.

The ED-HMI series products support adjusting backlight brightness and turning off the backlight. Some users have different brightness requirements for the LCD screen in different usage scenarios and wish to manually adjust the LCD screen's brightness or turn off the backlight to meet various scene needs. In response to this requirement, our company provides detailed operating instructions to help users correctly adjust the LCD screen's backlight brightness.

1.2 Scope of Application

This application applies to the following ED-HMI products.

ED-HMI2002-070C/101C
ED-HMI2020-070C/101C
ED-HMI2120-070C/101C
ED-HMI2220-070C/101C
ED-HMI2630-101C
ED-HMI3010-070C/101C
ED-HMI3020-070C/101C
ED-HMI3120-070C/101C
ED-HMI3630-101C

2 Application Guide

The methods for adjusting backlight brightness differ between Raspberry Pi OS (Desktop) and Raspberry Pi OS (Lite). The following sections provide detailed introductions for each.

2.1 Raspberry Pi OS (Desktop)

Describes the specific operations for adjusting backlight brightness and configuring automatic screen blanking on Raspberry Pi OS (Desktop).

2.1.1 Adjusting Backlight Brightness

Preparation:

The ED-HMI device has started normally and entered the desktop.

Steps:

Left-click the icon in the upper-left corner of the desktop, and select "Preferences" → "Screen Configuration" from the menu.

In the Screen Configuration interface, click "Screens" in the lower-left corner and then select "DSI-1". In the menu, select "Brightness", and then set the brightness percentage as needed. After setting the brightness percentage, click "Apply" in the lower-right corner to make the configuration effective.

TIP

The default screen name for the ED-HMI device is "DSI-1". Only "DSI-1" supports backlight brightness adjustment; an externally connected HDMI display does not support backlight brightness adjustment.
The adjustable range for backlight brightness is 0% to 100%.
If the backlight brightness is adjusted to 0%, the screen will go black.

2.1.2 Configuring Automatic Screen Blanking

When using the ED-HMI device, if there are scenarios with prolonged inactivity, users can configure automatic screen blanking. After configuration, the device will automatically blank the screen if there is no operation for 10 minutes. After the screen blanks, it can be restored by touching the screen.

Preparation:

The ED-HMI device has started normally and entered the desktop.

Steps:

Left-click the icon in the upper-left corner of the desktop, and select "Preferences" → "Raspberry Pi Configuration" from the menu.

Select the "Display" tab, enable "Screen Blanking", and then click "OK".

2.2 Raspberry Pi OS (Lite)

Describes the specific operations for adjusting backlight brightness and configuring automatic screen blanking on Raspberry Pi OS (Lite).

2.2.1 Adjusting Backlight Brightness

Supports turning the backlight on/off and adjusting brightness via command line.

Command	Description
echo 1 \| tee /sys/class/backlight/*/bl_power	Turn off screen backlight
echo 0 \| tee /sys/class/backlight/*/bl_power	Turn on screen backlight
echo x \| tee /sys/class/backlight/*/brightness	Adjust screen brightness, where the value range of x is 0~255

2.2.2 Configuring Automatic Screen Blanking

Preparation:

The ED-HMI device has started normally.

Steps:

Open a command terminal window and execute the following command to open the Raspberry Pi Software Configuration Tool (raspi-config) interface.

sudo raspi-config

In the main interface, select 2 Display Options and press Enter.

In the opened interface, select D2 Screen Blanking and press Enter.

In the opened prompt, select Yes and press Enter.

In the opened prompt, press Enter to confirm the configuration.

In the main interface, select Finish and press Enter to complete the configuration.

In the prompt, select Yes and press Enter to restart the device, making the configuration effective.