Troubleshooting of Pro face GP Series

Troubleshooting and Maintenance Guide for Pro face GP-2400/2500/2600 Series

In industrial automation sites, human-machine interface (HMI) is the core bridge between operators and control systems. The Pro face GP-2400, GP-2500, and GP-2600 series touch screens have been widely used in various production lines and equipment monitoring systems due to their stable performance, rich interfaces (Ethernet, CF cards, sound output, extended serial ports), and high reliability. However, as the equipment ages or the on-site environment changes, engineers often face a series of typical faults such as no display, communication interruption, unresponsive touch, backlight burning, and clock loss.

This article combines the technical manual and on-site maintenance experience of GP-2400/2500/2600 series to systematically sort out the common fault phenomena, root causes, diagnostic steps, and solutions of this series HMI, and provide preventive maintenance suggestions. Whether you are debugging an old production line or planning to replace spare parts, this article will become a practical portable guide.

Power and hardware installation failure: No display when turned on

1.1 Phenomenon Description

After connecting the power, the GP screen does not light up at all, the status LED does not light up or displays orange, or the screen lights up and immediately goes out.

1.2 Troubleshooting steps

Step 1: Check if the power input meets the model requirements

GP2500-TC11/GP2600-TC11 are AC power supply models: rated voltage AC100V (range AC85~132V) or AC85~265V (Revision 3 and above).

GP2400-TC41-24V、GP2500-LG41-24V、GP2500-SC41-24V、GP2500-TC41-24V、GP2600-TC41-24V  DC24V power supply model: allowable range DC19.2V~28.8V.

Be sure to use a multimeter to measure the input terminal voltage. Exceeding the allowable range may cause damage to the internal power board or protective action.

Step 2: Check the power terminal and fuse

The power terminals are located on the back of the GP and labeled as L, N (AC type) or "+", "-" (DC type). Confirm that the screws have been tightened with a torque of 0.5~0.6 N · m.

Some DC models do not have fuses inside, so it is necessary to check whether the external power supply circuit is short circuited or overloaded.

Step 3: Observe the color of the status LED

Green light constantly on: normal.

Orange: Backlight burnt out or GP internal malfunction (see backlight replacement section later for details).

Not lit: No power input or damaged power board.

Step 4: Forcefully enter offline mode for verification

Within 10 seconds after booting up, touch the top left corner of the screen (hidden switch) to enter the offline (OFFLINE) mode. If you can enter the offline menu but there is no screen in the running mode, it may be due to a damaged project file or a blank startup screen.

1.3 Typical Solutions

Voltage mismatch: Replace the power supply with one that meets the specifications or use a regulated power supply.

Backlight burning: Refer to section 5 for replacing the backlight. Attention: The touch screen still works after the backlight is burned out, which poses a risk of misoperation. The "Disable touch screen after backlight burning out" function should be enabled (enabled in initialization settings → touch screen settings).

Damaged power board: requires repair or replacement of the entire machine.

Communication failure: GP and PLC cannot exchange data

Communication failure is one of the most common alarms on site, and GP screens usually display "PLC COM. ERROR" and error codes such as 02: FD, 02: FE, 02: FC, etc.

2.1 Error Code Quick Reference Table

Solution to Error Code Meaning

02: FC communication parameters do not match (baud rate, data bits, stop bits, parity check). Check if the SET UP SIO settings of GP are completely consistent with the PLC programming port settings. Check the data format sent by the host when using Memory Link.

02: FE PLC does not respond. Check if the PLC is powered on; Confirm that the wiring is correct; Adjust the power on sequence - power on the PLC first, wait for 2-3 seconds, and then power on the GP.

02: FD receiving data errors are usually caused by communication cables being disconnected or strongly interfered with during operation. Check the cable connection, use shielded twisted pair, and ensure that the FG grounding resistance is ≤ 100 Ω.

02: F9 GP station number repetition (multi link n: 1 mode) When multiple GPs are connected to the same PLC, the STATION NO. (0~15) of each GP must be unique. Check the station number settings of all GPs.

The FB tag address is out of range. In Memory Link mode, the system data area address must be within the range of 0 to 2047; Or if the address range of the PLC is too small, the label allocation needs to be modified.

2.2 Hardware Connection Check

The serial port of GP-2400/2500/2600 is D-sub 25 pin (female socket), supporting RS-232C and RS-422. Definition of key pins:

RS-232C: 2-pin (SD), 3-pin (RD), and 7-pin (SG) must be connected; 4. Short circuit control lines such as 5, 6, and 8 as needed.

RS-422: Use 9 (TRMX), 10 (RDA), 11 (SDA), 15 (SDB), 16 (RDB), 18 (CSB) and 19 (ERB) short circuits, 21 (CSA) and 22 (ERA) short circuits, and add a 100 Ω terminal resistor between RDA and RDB.

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

Attention: GP2500L backlight users cannot replace it themselves and need to contact the supplier.

5.3 Replacement steps (taking CA3-BLU12-01 as an example)

Disconnect all power supplies from GP and unplug the power cord.

Remove the three interface covers and use a Phillips screwdriver to remove the seven screws from the back cover.

Open the back cover from the top (with hinges at the bottom).

Loosen the 3 fixing screws of the circuit board and open the circuit board.

Unplug the backlight power connector (1).

Loosen the backlight fixing screw, slide the backlight to one side and remove it upwards.

Install the new backlight and reverse the operation to restore it.

Safety Warning: Power off before replacement; The backlight tube is fragile and operates at high temperatures; Avoid touching the glass tube.

CF card usage and data backup failure

The GP-2400/2500/2600 series comes standard with a CF card slot, which can be used for screen program transfer, data recording, recipe storage, and more.

6.1 CF card cannot be recognized or read/write errors occur

Card slot cover detection: GP's CF card slot has a physical cover switch, and the CF card cannot be accessed when the cover is opened. The CF card access LED will only light up after the cover is closed. If the cover plate is damaged, turn the DIP switch 4 on the back to ON (force off detection).

Support capacity: It is recommended to use Pro face original cards (64MB/128MB/256MB/512MB). Using non original cards may cause instability.

Initialization: Format in OFFLINE → Initialize Memory → Initialize CF CARD (will delete all data).

6.2 Memory Loader Tool failed to start

Phenomenon: Three repeated beeps when turning on, or no response from CF BOOT.

Reason: MLD * * * *. SYS or IPL.SYS files are missing from the CF card.

Solution: Remake the Memory Loader Tool onto the CF card using GP Pro/PBIII on the PC to ensure file integrity.

6.3 Data Writing Lifespan

The erase life of CF card is about 100000 times (calculated based on writing 500KB per time). Regularly backup CF card data to PC and avoid frequent recording.

Clock error and battery replacement

7.1 Phenomenon

Reset the boot time to 2000/01/01 each time.

Unable to save new time after entering SET UP TIME.

The screen displays' CLOCK SET UP ERROR '.

7.2 Reasons

The internal lithium battery voltage is depleted. This battery is used to maintain SRAM (recipe, alarm history) and real-time clock. Battery life:

Expected lifespan at ambient temperature

≤ 40 ℃ for more than 10 years

≤ 50 ℃ for more than 4.1 years

≤ 60 ℃ for more than 1.5 years

7.3 Handling Methods

Users are strictly prohibited from replacing batteries on their own, as lithium batteries may explode. Please contact your local dealer for replacement. Before replacement, keep the GP continuously powered on for 24-96 hours to perform trickle charging on the battery (rechargeable models only, some older models are disposable batteries). If the time cannot be maintained after charging, it must be sent for repair.

Offline mode and self diagnostic tool

The offline mode of GP is the core entry point for troubleshooting. Entry method:

Touch the top left corner of the screen within 10 seconds after booting up.

In RUN mode, force reset to bring up the menu bar: hold down the bottom right corner, press the top right corner, and finally press the bottom left corner (three finger operation), click "OFFLINE".

8.1 Common self diagnostic items

Select SELF-DIagnoSIS from the OFFLINE main menu to perform the following key tests:

Test item functionality applicable scenarios

LAY PATTERN check LCD display pattern, buzzer, KANJI ROM checksum display abnormality, no buzzing

TOUCH PANEL touches the grid one by one to verify that the touch layer is malfunctioning

SIO CHECK needs to return to the loop line, and the RS-232C/422 transceiver communication is unstable during testing

PRINTER I/F printing ASCII character set printer has no output

CF CARD read-write test CF card error

SOUND I/F playing "Do Re Mi" sound output fault

EXPANSION Serial I/F Test: The barcode gun and serial device are not communicating

8.2 Force Factory Reset

If the screen data is damaged and unable to start, the following methods can be used:

Serial port forced transfer: Select "Transfer Settings" → "Force System Setup" in GP Pro/PBIII on the PC, then connect GP and automatically enter transfer mode after power on.

CF card forced start: Turn DIP switch 1 on the back panel to ON, insert a CF card containing Memory Loader Tool, and automatically restore the system from the CF card after power on.

Common error codes and detailed countermeasures

9.1 SYSTEM ERROR (03:xx)

Appears when there is a data transmission interruption or power fluctuation on the screen. Solution:

Check that the power and signal lines are wired separately and that FG is properly grounded.

Transfer screen data again (using Force System Setup).

If there are other communication errors, solve the communication problem first.

9.2 ILLEGAL ADDRESS IN SCREEN DATA

Tag addresses overlap. For example, the T-tag (trend chart) address conflicts with the system data area address. Address reallocation is required in GP Pro/PBIII to ensure no overlap.

9.3 SCREEN TAG LIMIT EXCEEDED

Each screen has a maximum of 384 tags. After exceeding the limit, the excess part will be disabled from the last registration window and loading screen. Reduce the number of single screen labels or split screens.

9.4 D-Script / Global D-Script Error

Error 001: The number of global D scripts exceeds 32.

Error 002: The total number of devices in the global D script exceeds 255.

Error 003: The called function does not exist.

Error 004: Function nesting exceeds 10 layers.

Check script logic, reduce global scripts or merge device references.

Suggestions for preventive maintenance cycle

To ensure the long-term stable operation of GP-2400/2500/2600 series, it is recommended to conduct inspections according to the following cycles:

Project cycle content

Install the sealing gasket once a year to check for aging and cracking, and replace it if necessary (GP-2400 uses PS400-WP00-MS; GP-2500/2600 using GP570-WP10-MS.

Replace the backlight kit if the backlight has accumulated 50000 hours or the brightness has significantly decreased.

Contact the dealer to replace the lithium battery for 3-5 years (below 40 ℃) and keep the clock accurate.

CF card data backup logs and formulas to PC every month to prevent card damage.

Tighten the power and communication terminals every six months for grounding and wiring, and measure the grounding resistance to be ≤ 100 Ω.

Clean the ventilation holes on the back cover every quarter to ensure unobstructed natural cooling.