QDX50A Digital Pressure Gauge User Manual

1. Product Overview

The QDX50A Digital Pressure Gauge is a high-precision measuring instrument designed for various applications. It utilizes a high-quality pressure sensor core, ensuring accuracy, corrosion resistance, impact resistance, vibration resistance, low temperature drift, and excellent stability. Its low-power consumption battery design allows for long-term operation without external power, making installation and use straightforward.

This versatile gauge can measure gage pressure, absolute pressure, and differential pressure, and is suitable for use with gas, liquid, oil, and water mediums. It overcomes the limitations of traditional pointer pressure gauges, offering superior reliability and performance, especially in corrosive and high-vibration environments. The product is widely used across petroleum, chemical, aviation, and other industrial sectors.

Figure 1: QDX50A Digital Pressure Gauge

2. Specifications

Figure 2: Technical Parameters Table

3. Features

• High Accuracy: 0.5% measurement accuracy, with options for 0.2%FS or 0.5%FS.
• Robust Design: Features 304 stainless steel housing for durability and shock resistance, and IP65 shell protection for dustproof and waterproof performance.
• Advanced Sensor: Equipped with an imported pressure sensor chip for high stability and effective EMC resistance, capable of handling up to 150% overload pressure.
• Digital Anti-Jamming Circuit: Ensures long-term stability and reliable operation.
• Multi-Purpose: Suitable for measuring pressure in various mediums including gas, liquid, oil, and water.
• Easy to Use: Low power consumption with 2x AA batteries, providing long-term power supply without external power.
• Customizable: Supports customized pressure ranges and various thread types (e.g., M20*1.5, G1/4, G1/2, NPT1/4).
• Quality Assurance: Undergoes 6-time cyclic calibration and 48-hour high-temperature aging test.

Figure 3: Key Features and Quality Assurance

Figure 4: Overload Pressure and Sensor Technology

Figure 5: Digital Anti-Jamming Circuit for Stability

Figure 6: Multi-Purpose Application

4. Installation

1. This precise measuring instrument should be used in a well-ventilated, easy-to-observe, maintainable, and non-corrosive environment.
2. Digital pressure gauges should be installed vertically for easy reading and accurate measurement.
3. When installing the digital pressure gauge, it is necessary to use appropriate sealing accessories, such as copper or PTFE gaskets, to ensure a proper seal.
4. This series of instruments can be used with a desktop pressure pump. Pay close attention to matching the pressure range when using.
5. When installing and disassembling, use the correct tool to work on the hexagon of the pressure gauge joint. It is strictly forbidden to twist the gauge head by hand.

Figure 7: Dimensional Drawing for Installation Reference

5. Operation

5.1. Instrument Usage Functions

• ON/OFF: Long press the "ON/OFF" button for 2 seconds or more to turn the instrument on or off.
• ZERO: When the instrument is not pressurized and zero drift occurs, press the "ZERO" button 3 times to reset to zero. Important: Do NOT press "ZERO" when the instrument is under pressure.
• Full Range Query and Unit Switching:
  • To query the full range, long press the "ZERO" button for 2 seconds or more. The display will show the maximum range of the instrument.
  • While in this full range display page, short press the "On/Off" button to cycle through pressure units: MPa → Pa → mmH2O → kPa → Psi → mH2O → Kgf/cm² → MPa.
  • To save the selected pressure unit, long press the "Set" button for 2 seconds or more.

Figure 8: Button Functions and Display

6. Battery Management

6.1. Battery Undervoltage Indication

When the electricity symbol on the display flickers, it indicates a low battery. Please replace the batteries immediately. Failure to do so may result in low brightness, inaccurate measurements, and inaccurate readings.

6.2. Battery Replacement

• For 304 Stainless Steel Instruments: Gently counter-rotate the upper cap buckle by more than 15 degrees to open the back cover. Install 2x AA batteries.
• For ABS Instruments: Locate the protruding buckle cap on the back cover. Gently open this buckle cap to install 2x AA batteries.

Figure 9: Battery Type and Location

7. Maintenance

• Ensure the instrument is always used in a well-ventilated, non-corrosive environment to prolong its lifespan.
• Regularly check the battery level and replace batteries promptly when the low battery indicator appears to maintain optimal performance and accuracy.
• Avoid twisting the gauge head by hand during installation or disassembly; always use appropriate tools on the hexagon of the joint.
• Store the device in a dry environment within the specified ambient temperature range (-10~60°C) and humidity (≤80%RH).

8. Faults and Troubleshooting

The following list outlines common issues and their troubleshooting methods:

1. No numbers on the screen:
   • Solution: Change the batteries.
2. Pressure increases but the number remains unchanged:
   • Solution: Remove the battery and wait 10 seconds before reinstalling it.
3. Non-digital numbers, ink leakage, cracks, or LCD screen damage:
   • Solution: This indicates a hardware fault. The unit requires factory repair.
4. Accuracy changed:
   • Solution: The unit requires factory re-calibration.

Figure 10: Internal Circuit Diagram

9. Certifications

The QDX50A Digital Pressure Gauge has obtained multiple quality certifications, including CE, FCC, and RoHS, ensuring compliance with international standards for safety and environmental protection.

Figure 11: Product Certifications

10. Warranty and Support

This product comes with a 3-year warranty. For any technical support, service inquiries, or to report issues not covered in this manual, please contact your vendor or the manufacturer directly.

A detailed user manual in PDF format is available for download: View User Manual (PDF)