Temperature and humidity sensor selection and application skills - Solutions - Huaqiang

Kaixin micro test

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Test probe PH-5H

When selecting a temperature and humidity sensor, it's essential to consider several key factors such as the measurement range, accuracy, drift characteristics, and environmental conditions. These sensors are widely used in various industries, from weather monitoring to industrial control systems. However, choosing the right one requires careful evaluation of your specific needs and the operating environment.

1. Determine the Measurement Range

The first step is to identify the required measurement range. For most general applications, a full range (0–100% RH) isn't necessary. In many cases, a narrower range can be sufficient, especially when the application doesn't require extreme precision. It's important to match the sensor's capabilities with the actual conditions you'll encounter.

2. Choose the Right Accuracy

Accuracy is one of the most critical parameters when selecting a humidity sensor. While higher accuracy might seem appealing, it often comes at a significant cost. A ±5% RH accuracy is usually adequate for general use, especially in environments where temperature control is not precise. However, in controlled environments like laboratories or cleanrooms, a higher accuracy of ±3% RH or better may be required. Keep in mind that even the best sensors can experience errors due to temperature fluctuations, which can affect readings by up to 0.5% RH per 0.1°C change.

3. Consider Drift Over Time and Temperature

Over time, humidity sensors can experience drift due to exposure to dust, oil, and other contaminants. This can lead to reduced accuracy and reliability. Most sensors have an annual drift of around ±2%, so regular calibration is essential. Manufacturers typically recommend recalibrating every 1–2 years, depending on usage and environmental conditions.

4. Environmental Protection and Installation

Humidity sensors are generally non-sealed, making them vulnerable to damage in harsh environments. Avoid using them in areas with high acidity, alkalinity, or organic solvents. Also, ensure the installation location allows for proper air circulation and isn't too close to walls or corners. If the space is large, multiple sensors may be needed for accurate readings. Additionally, some sensors are sensitive to power supply stability, so it's crucial to follow manufacturer guidelines for power requirements.

5. Additional Selection Criteria

When choosing a temperature and humidity sensor, consider factors like output type, installation method, gas compatibility, and material durability. The sensor should be able to withstand environmental stressors such as condensation, extreme temperatures, and chemical exposure. Cost-effectiveness is also important—don’t just focus on price but evaluate long-term performance, maintenance, and verification costs.

6. Reliability and Brand Reputation

Choose a sensor from a reputable manufacturer with a proven track record. Look into the brand’s history, market presence, and user reviews. High-quality sensors tend to last longer and perform more reliably. Some models allow for interchangeable probes, which can increase flexibility and reduce long-term costs.

7. Maintenance and After-Sales Support

Regular maintenance is necessary to keep the sensor functioning properly. This includes cleaning, replacing parts, and recalibration. Ensure that the supplier offers good after-sales support, including repair services and spare parts availability. A reliable warranty and service agreement can provide peace of mind and reduce downtime.

By carefully evaluating these factors, you can select the ideal temperature and humidity sensor for your specific application, ensuring accurate measurements, long-term reliability, and cost-effective operation.