Troubleshooting of Pro face GP Series

Common error: When using RS-422, the user did not short-circuit CSB-ERB and CSA-ERA, resulting in abnormal signal levels. Be sure to weld the internal jumpers according to the manual.

2.3 Software Settings Verification

Enter OFFLINE mode → Initialize → SET UP I/O → SET UP SIO, check:

Communication Rate: Consistent with PLC (2400~115200bps)

Data Length: 7 or 8 bits

Stop Bit: 1 or 2 bits

Parity：None/Odd/Even

Communication Format: RS-232C or RS-422 (4-wire)

If "Serial I/F CHANGE" is enabled (swapping COM1 and COM2), the extended serial port (COM2) is used for PLC communication, and the parameters need to be set in EXPANSION Serial Communication SETUP.

2.4 Power on sequence and interference elimination

Many communication anomalies are caused by the power on sequence: PLC starts slowly, GP initiates communication immediately after power on but does not receive a response. Solution:

Set START TIME to 2-5 seconds in SYSTEM SETUP to delay GP startup and wait for PLC to stabilize.

Communication cables must be routed separately from power lines, using shielded cables and single ended grounding.

Touch screen response is abnormal or completely unresponsive

3.1 Fault Symptoms

There is no response when touched, and the buzzer does not sound.

Slow touch response, requiring multiple presses.

Some areas cannot be touched.

3.2 Diagnostic steps

Check the touch operation mode: enter OFFLINE → Initialize → SET UP TOUCH PANEL, confirm that the "TOUCH Operation MODE" is set to "One Point" or "Two Point" instead of "No Slide" (sliding is invalid in this mode, but single points should still be valid).

Touch buzzer setting: If "TOUCH BUZZER SOUND" is set to OFF, there will be no feedback sound, but the touch function is normal; Can be temporarily activated for judgment.

Run self diagnosis: OFFLINE → SELF-DIagnoSIS → TOUCH PANEL. The screen will display a grid, touch each grid one by one, and the corresponding grid should be highlighted. If some cells do not respond, the touch layer is damaged.

Backlight burning impact: After the backlight is burned, users may accidentally trigger the operation by touching it, thinking that the screen is turned off. But the touch itself still works normally. Touch can be disabled by setting the "USE TOUCH PANEL AFTER BACK LIGHT BURNOUT" option to "NO".

3.3 Calibration and Repair

The GP-2400/2500/2600 series does not have a user executable touch calibration program (unlike Windows CE devices). The touch accuracy is determined by hardware. If a large area of failure is detected through self diagnosis, it is usually necessary to replace the touch panel or the entire machine.

Display issues: screen flickering, abnormal colors, or residual images

4.1 Screen flicker or abnormal brightness

STN color model (GP-2500S): Flashing may occur when the ambient temperature is too high or the brightness setting is too low. Solution: Go to Initialize → SET UP PLAY DEVICE, adjust the REFRESH RATE (+direction increases refresh rate, up to+18 levels). Simultaneously reduce the ambient temperature to ensure ≤ 40 ℃.

Brightness adjustment: In RUN mode, press and hold the bottom right and bottom left corners simultaneously to bring up the brightness adjustment bar. The lower the brightness, the more energy-efficient it is, but too low may cause flickering.

4.2 Residual image (burn-in)

After displaying the same static image for a long time, switching screens will leave behind the previous residual image. This is the physical characteristic of LCD. Preventive measures:

Enable Stand by Mode: Set the standby time (0-255 minutes) in SYSTEM SETUP, and automatically turn off the backlight after no operation.

Control the screen display to turn off through the system data area: write FFFFh to the "Screen Display Off" address.

Regularly switch screens or use screen protectors.

4.3 Color display error

Confirm the color mode in the project file: GP-2400/2600T supports 256 colors (no flicker) or 64 colors (3-speed flicker). If 256 colors are selected, all flashing functions will be disabled.

For the GP-2500L monochrome model, the grayscale mode needs to be selected as "MONOCHOME 8 HUES" in GP Pro/PBIII and the display effect needs to be confirmed.

Backlight burn detection and replacement

5.1 Identify backlight burn out

The status LED turns orange.

The screen is dark, but there is still a buzzing sound when touched and it can enter offline mode (proving that the host is working properly).

The system data area bit10 (status word) becomes ON.

Warning: After the backlight is burned out, the touch screen can still be operated. If the operator is not aware, it may trigger dangerous actions by mistake. Be sure to set "USE TOUCH PANEL AFTER BACK LIGHT BURNOUT" to "NO" in SET UP TOUCH PANEL to automatically disable touch.

5.2 Backlight Model Comparison

GP model revised version backlight model

GP-2400T series all PS400-BU00-MS

GP-2500T series all GP577RT-BL00-MS

GP2600-TC11 Rev. 4 Mark CA3-BLU12-01

GP2600-TC41-24V Rev. 3 Mark CA3-BLU12-01

GP2600-TC11 Rev. 4 unmarked PS600-BU00

GP2600-TC41-24V Rev. 3 unmarked PS600-BU00