Frequently Asked Questions

FAQ

What communication protocols do GPT LCM serial HMI support?

All GPT LCM serial HMI modules support UART (TTL level), RS232, and RS485 communication protocols.

What is the operating temperature range of serial HMI?

Standard operating temperature is -20°C to +70°C. OLED series can reach -40°C to +70°C.

How to get development documentation and sample code?

Contact us and our engineers will send the complete development package via email or WeChat.

What is the minimum order quantity for serial HMI?

No MOQ for samples. Production orders typically start from 100 units.

What development platforms does TFT serial HMI support?

Serial HMI communicates via UART, making it platform-independent. It works with any MCU or development board.

How to quickly select the right model?

Contact us with your requirements. Our engineers will recommend the most suitable model within 24 hours.

What is the difference between serial HMI and parallel HMI?

Serial HMI communicates via UART, requiring only 2 wires (TX/RX), making development simple. Parallel HMI requires many GPIO pins and complex timing control. Serial HMI is ideal for rapid development and resource-constrained MCUs.

How to choose between UART, RS232, and RS485?

UART (TTL) is for short-distance board-level communication (<1m). RS232 is for point-to-point within 15m with good noise immunity. RS485 supports up to 1200m and multi-device bus topology. All GPT LCM serial HMI support all three interfaces.

How to choose between TFT color LCD and OLED display?

Choose TFT for industrial control and medical instruments (high brightness, long lifespan, lower cost). Choose OLED for wearables and premium instruments (high contrast, fast response, wide viewing angles). TFT covers 0.96"~8", OLED covers 0.42"~2.23".

Which MCU platforms are compatible with serial HMI?

Serial HMI uses standard UART, compatible with virtually all MCUs with serial ports. Common platforms include STM32, Arduino, ESP32, 8051, PIC, Raspberry Pi, and Pico. We provide sample code and technical support for all platforms.

What certifications do serial HMI modules have?

All products are certified with CE, RoHS, and FCC. Some also have UL and medical device certifications. All comply with REACH. Certification reports available upon request.

What is the customization process for serial HMI?

5-step process: 1) Provide requirements (size/resolution/interface/housing) → 2) Feasibility evaluation and quote → 3) Mold/sample production after confirmation (2~4 weeks) → 4) Testing and acceptance → 5) Mass production. Standard products skip mold step with shorter lead time.

What is the lead time and MOQ for serial HMI?

Standard products ship in 3~5 business days when in stock, MOQ 1 piece. Custom products: samples in 2~4 weeks, mass production in 4~6 weeks, MOQ varies by project. We support both small-batch fast delivery and large-volume stable supply.

What is the operating temperature range? What is the difference between industrial and commercial grade?

Standard products: -20°C to +70°C (commercial grade). Industrial grade: -30°C to +80°C. OLED series: -40°C to +70°C. Industrial-grade products use wider temperature range LCD materials for outdoor and factory environments.

What is the power consumption of serial HMI?

1.8 inch serial HMI: about 30~50mA (5V). 3.5 inch: about 80~120mA. 7 inch: about 200~350mA. Turning off backlight reduces power by over 60%. Detailed power specs available for all models.

What display effects and animations does serial HMI support?

Serial HMI supports image display, text, progress bars, sliders, buttons, charts, and animations. Supports BMP/JPG/PNG images, TrueType fonts, and multi-language (Chinese, English, Japanese, Korean, etc.). UI design via drag-and-drop software — no programming required.

What is the maximum baud rate for serial HMI?

Standard baud rate range: 1200~921600bps. Default: 9600bps or 115200bps. Recommended: 115200bps for optimal speed and stability. At high baud rates, use shielded cables and keep distance under 15m (UART).

How to send commands to display text and images on serial HMI?

Send ASCII or hex commands via serial port. For example, sending "t0.txt=\"Hello\"" displays "Hello" on the t0 control. Images are displayed by image ID. We provide complete command set manuals and sample code for all platforms.

Does serial HMI support touch screen?

Yes, we offer both resistive and capacitive touch options. Resistive touch supports single-point, lower cost, suitable for industrial use (operable with gloves). Capacitive touch supports multi-point, high sensitivity, ideal for consumer products. Touch events are reported via serial port coordinates.

Can serial HMI be used outdoors?

Yes. We offer high-brightness (1000+ nits) outdoor-readable models, clearly visible in direct sunlight. Industrial grade operates at -30°C~+80°C, with optional IP65 waterproof rating. Suitable for outdoor EV chargers, agricultural equipment, and vehicle terminals.

What is the lifespan of serial HMI?

TFT backlight lifespan: about 30,000~50,000 hours (3~6 years continuous). OLED: about 50,000~100,000 hours. Reducing brightness and avoiding static images extends lifespan.

What are the advantages of GPT LCM serial HMI over other brands?

GPT LCM has 21 years of display module R&D experience, certified as a National High-Tech Enterprise. Advantages: 1) Full range 0.96"~8"; 2) All three serial interfaces supported; 3) Free UI design software; 4) 24-hour tech support; 5) Small batch customization; 6) Fast delivery — standard products ship in 3~5 days.

Can serial HMI play videos?

Some high-end models support video playback via serial commands (AVI format). Resolution and frame rate depend on the specific model. Ideal for product demos and advertising.

What is the supply voltage for serial HMI?

Standard supply: 5V (USB or DC). Some models support 3.3V or 12V. Use a stable power supply with ripple under 50mV. Screens 7 inch and above should use dedicated power supply.

What is the development software for serial HMI?

We use a free desktop UI design software for Windows. Features include drag-and-drop UI design, image/font import, widget configuration, simulator preview, and firmware upgrade. No programming required — design interfaces quickly.

Can serial HMI connect to WiFi or Bluetooth?

Serial HMI does not have built-in WiFi/Bluetooth, but you can connect via an external MCU (e.g., ESP32) that handles WiFi/Bluetooth and communicates with the serial HMI via UART. We provide ESP32 + serial HMI networking reference designs.