Ensuring Precision: A Guide to Touch Calibration on MCGS HMIs

Mcgs (Configuration Software) HMIs, produced by Beijing Kunlun Tongtai, are widely used in industrial automation for their stability and ease of use. However, like all resistive touch screens (common in many MCGS models), they can drift over time due to aging, temperature changes, or physical impact. When your button presses no longer match the intended input, it’s time for a touch calibration.

Method 2: Via the System Menu (If the Screen is Still Usable)

If you can navigate but taps are just slightly off:

  1. Boot the HMI until your project loads.
  2. Tap the upper-left corner of the screen repeatedly (about 5 times fast) during the first 10 seconds of boot.
  3. This opens the MCGS System Settings.
  4. Navigate to: Maintenance → Touch Calibration.
  5. Follow the crosshair prompts as above.

Part 2: Pre-Calibration Checklist – Do Not Skip This

Calibration is a delicate process. Interrupting it or performing it incorrectly can leave your HMI in an unusable state. Follow these steps before starting:

  1. Clean the Screen: Use a microfiber cloth with a mild screen cleaner. Oil, grease, or dried liquids cause false touches.
  2. Check for Physical Damage: If the glass is cracked or the bezel is bent, calibration will not fix the issue – you need a hardware replacement.
  3. Save Open Projects: Calibration will temporarily override the running application. Ensure no critical processes are being monitored or controlled.
  4. Use the Proper Tool: For resistive screens, use a stylus or a blunt non-metallic tool (e.g., a pen cap). Fingernails are too sharp; fingers are too soft.
  5. Ensure Stable Power: Do not perform calibration during a brownout or on battery backup unless absolutely necessary.

6. Emergency USB Recovery Calibration

For completely dead touch input:

  1. Create a USB drive with mcgs_calib.txt (empty file) or use the manufacturer’s calibration script (contact Kinco support).
  2. Insert USB → power on.
  3. The HMI enters forced calibration mode automatically.

5. Troubleshooting: Calibration Won’t Stick

If calibration resets after reboot:

Step-by-Step Instructions:

  1. Power On the HMI: Wait for the MCGS runtime to fully load. You are now looking at your project’s main screen.
  2. Access the System Menu:
    • Method A: In most MCGS configurations, press and hold the top-left corner of the screen for 5-10 seconds. A hidden blue or gray system menu will appear.
    • Method B: If Method A fails, power cycle the HMI. Immediately upon reboot, repeatedly tap the screen (anywhere) as soon as the backlight turns on. This sometimes interrupts the boot sequence and loads the system menu.
  3. Navigate to Touch Calibration: Inside the system menu, look for an icon or text labeled one of the following:
    • Touch Panel Calibration
    • Pen Calibration
    • Digitizer Calibration
    • Control Panel → Stylus → Calibration
  4. Start the Calibration: Tap the icon. The screen will turn white (or light grey) and display crosshairs (+) or a bullseye target.
  5. Follow the Crosshairs: Using your stylus or tool, press the center of each target firmly and accurately. Do not slide – tap, lift, tap the next.
    • Resistive: Press until you hear a slight "click" or feel the top layer depress.
    • Capacitive: Use a light, direct finger touch.
  6. Complete the Sequence: Typically, there are 5 or 9 points (corners and center). After the last point, the device may ask you to press "OK" or "Confirm" to save the new calibration data.
  7. Save and Exit: The HMI will often reboot automatically. If not, return to the system menu and select Exit or Run.

Why Does an MCGS HMI Lose Touch Calibration?

Before turning screws or tapping screens, understand the root cause. The MCGS uses a resistive touch overlay. Unlike a smartphone (capacitive), resistive screens rely on physical pressure. Two conductive layers touch when you press the screen, creating a voltage change.

Calibration fails for three primary reasons:

  1. Thermal Drift: Temperature fluctuations in control cabinets cause the screen substrate to expand and contract.
  2. Mechanical Aging: Repeated presses create micro-indentations, shifting the "center" of a touch coordinate.
  3. Voltage Fluctuation: Noisy power supplies (common in factories) can corrupt the analog-to-digital conversion of touch coordinates.

When the screen’s calculated coordinate map no longer matches the LCD’s physical pixel grid, you need a fresh calibration.

Introduction

In the world of industrial automation, the Human-Machine Interface (HMI) serves as the critical bridge between operators and complex machinery. Among the most popular and reliable HMI brands on the market is MCGS (Micro Computer Graphics System) — a product of Beijing Kunlun Tongda Technology. Renowned for their cost-effectiveness, robustness, and versatility, MCGS HMIs are found in manufacturing plants, energy management systems, environmental monitoring stations, and countless other industrial applications.

However, like any touch-based device, MCGS HMIs can drift over time. A button that used to respond perfectly might suddenly require a firmer press; a numeric keypad might register a "5" when you touched "6." This phenomenon is known as touch misalignment, and it is rectified through a process called touch calibration.

This article serves as the ultimate guide to MCGS HMI touch calibration. We will explore why calibration is necessary, step-by-step methods (including touchscreen and touchpad calibration), troubleshooting common issues, and best practices for long-term HMI health.