Product Technical Q&A and Service Consultation

The IEC 61672-1 standard classifies sound level meters into Class 1 (precision) and Class 2 (general). Class 1 has an allowable error of approximately ±0.7 dB across the full frequency range, while Class 2 is approximately ±1.0 dB. In routine environmental noise measurements, the difference between their readings typically does not exceed 1 dB.

Recommendation: Choose Class 1 for scenarios requiring authoritative reports, such as regulatory enforcement, laboratory acoustic research, and product noise quality certification. For factory floor inspections, self-checks of construction noise, equipment acceptance, and routine environmental monitoring, Class 2 is sufficient.

ET-958, ET-953, and ET-973 comply with IEC 61672-1 Class 2 standards, offer a measurement resolution of 0.1 dB, and sample at 2 samples/sec. We can also arrange third-party calibration through CNAS-accredited laboratories to issue official certificates.

Time weighting determines the instrument's response speed to sound variations.

FAST time constant is 125 ms. Readings follow noise fluctuations closely, making it ideal for measuring rapidly changing sound sources such as traffic noise, impulsive noise, and equipment start-stop events.

SLOW (Slow) time constant is 1 seconds, providing steadier readings that are easier to read and record manually. This setting is recommended for most steady-state noise assessments.

When measuring equivalent continuous sound level (Leq), it is recommended to also record MAX and MIN values to assess noise fluctuation. ET-958 and ET-973 support fast/slow response switching, along with MAX/MIN recording and data hold functions.

Calibrate every 12 months with a third-party metrology laboratory. If the device is used frequently, operates in harsh environments (dust, high humidity, or extreme temperature fluctuations), or has been dropped or impacted, reduce the interval to 6 months.

Perform on-site verification with a sound calibrator (commonly 94 dB / 114 dB @1000 Hz) before each measurement. If the reading deviation exceeds 0.5 dB, remove the device from service for inspection. Moisture or dust accumulation on the microphone diaphragm can also cause reading drift; keep it dry and use a windscreen during daily operation.

Each sound level meter undergoes individual calibration and a 72-hour aging test before leaving our factory. We can also assist in submitting units to third-party accredited laboratories for CNAS-certified calibration, ensuring full traceability of measurement data.

The two methods operate on different principles and are suited to distinct wind speed ranges.

Thermal anemometers measure wind speed by calculating the heat dissipation rate of a heated element. They can detect low-velocity airflow from 0.05 to 0.3 m/s, offer fast response times, and are ideal for cleanroom airflow testing, ventilation duct velocity measurements, and indoor air quality assessments. A drawback is their fragile probe, making them unsuitable for dusty or oily airflows.

The vane anemometer calculates wind speed based on rotor rotation. Built to be durable and resistant to contamination, it typically measures from 0.4 to 35 m/s. Ideal for outdoor wind speed monitoring, fan performance testing, and HVAC outlet detection. Limitation: difficult startup at low speeds.

ET-975P and ET-975 use a thermal solution with a resolution of 0.01 m/s. The ET-95 intelligent anemometer uses a vane solution, measuring from 0.4 to 35 m/s with an accuracy of ±3% and built-in temperature compensation.

Airflow (m³/h) = Average Air Velocity (m/s) × Cross-Sectional Area (m²) × 3600.

Measurement procedure: Arrange at least 5 to 9 measurement points on the duct or air outlet cross-section using the equal-area method. Measure wind speed at each point, calculate the arithmetic mean, then multiply by the cross-sectional area. Directly multiplying a single-point wind speed by the area yields significantly inflated results because velocity is higher near the center than near the walls.

For rectangular vents, also consider the effective ventilation area coefficient (typically 0.7~0.85); otherwise, the calculated result may be overestimated.

ET-95 Smart Anemometer automatically calculates airflow after you input the duct size. The ET-975P features max/min/average statistics, large-capacity data storage, and USB Type-C export for easy debugging and record-keeping.

HVAC testing focuses on three key areas: low air velocity resolution, temperature compensation, and data logging.

Supply air velocity typically ranges from 0.5 to 3 m/s, with return air velocities being lower. A thermal probe with a resolution of 0.01 m/s is required for stable readings. Significant temperature differences between the airflow in the duct and room temperature can cause reading errors of 3% to 8% without temperature compensation. During system commissioning, multi-point data must be retained as acceptance evidence, making data storage and export features highly practical.

ET-975P features a 2.8-inch color LCD, supports comprehensive THW (temperature, humidity, wind) measurement and human-perceived temperature calculation, with LED and audible alarms. Ideal for on-site commissioning and acceptance documentation.

Standard 4-in-1 configuration detects combustible gas (LEL), oxygen (O₂), carbon monoxide (CO), and hydrogen sulfide (H₂S).

Common alarm thresholds: combustible gas low alarm 10% LEL, high alarm 25% LEL; oxygen low alarm 19.5% VOL, high alarm 23.5% VOL; carbon monoxide low alarm 25 ppm, high alarm 50 ppm; hydrogen sulfide low alarm 10 ppm, high alarm 15 ppm.

Actual thresholds must be determined based on local regulations and corporate safety protocols; some industries adopt stricter Level 1 alarm values for hydrogen sulfide.

GD-100 Portable Multi-Gas Detector supports multi-level alarm thresholds, features triple alerts (sound, light, vibration), offers IP65 protection, provides 12 hours of battery life, and stores up to 10000 data records.

Catalytic combustion sensors are used for combustible gas (LEL) detection. They offer low cost and fast response but are susceptible to poisoning by silicon compounds, sulfides, and lead compounds, which renders them inoperable. Their normal lifespan is 2–3 years. An oxygen concentration of at least 10% is required for proper operation.

Electrochemical sensors detect gases such as CO, H₂S, O₂, SO₂, and NO₂. They offer high selectivity with resolution down to 1 ppm and a typical lifespan of 2–3 years, requiring regular calibration. Prolonged storage without power accelerates electrolyte drying; we recommend keeping the sensor powered on periodically.

Infrared sensors offer high resistance to poisoning, a lifespan exceeding 5 years, and do not require oxygen for operation. However, they are more expensive, making them ideal for silicon-rich or oxygen-deficient environments.

Our multi-gas detector features independent sensor modules, allowing individual sensors to be replaced upon expiration without scrapping the entire unit.

Diffusion-based sensors rely on natural gas diffusion, offering a compact size, low power consumption, and no need for sampling accessories. Ideal for personal wearables and open-area inspections.

Pumped internal sampling pump. Draws gas from distant locations via a sampling probe and hose to the sensor. Ideal for pre-entry confined space gas detection, as well as hard-to-reach areas such as pipes, tanks, and underground manholes.

Before entering tanks, pipelines, basements, or sewer wells, use a pump-aspirated detector to perform external testing following the "ventilate first, test second, work last" procedure. Testing points must cover the upper, middle, and lower levels of the confined space.

Our 5-in-1 and 7-in-1 models feature built-in pump sampling, with response times under 10 seconds and 8 seconds respectively. The 7-in-1 model offers over 16 hours of battery life.

Detectors used in explosive environments such as petrochemical plants, coal mines, gas stations, and gas terminals (especially fixed units) must be explosion-proof certified. The GD-200 fixed gas leak alarm features an explosion-proof design compliant with Ex d IIC T6 standards. It supports 4-20mA standard signal output and RS485 communication, enabling integration with DCS/PLC systems for 24-hour continuous monitoring.

Export: CE certification required for the EU market, FCC certification for North America. Some customers also require RoHS and REACH reports.

CE and FCC certified. We provide relevant certification documents for your target market and support OEM/ODM customization of alarm thresholds, interface languages, and housing designs.

Both share the same detection objectives, but their use cases dictate different design priorities.

Camping scenarios prioritize lightweight design, battery life, and multi-modal alerts. Due to complex noise environments around tents, RVs, and wood-burning stoves, single-sound alarms are easily missed; therefore, devices must feature triple alerts combining sound, light, and vibration. Equipment should support magnetic mounting or hanging loops and meet at least IP54 protection against water splashes and dust. A low-power solution ensures continuous monitoring throughout multi-day camping trips.

Industrial scenarios prioritize explosion-proof certification, data logging, and system integration, typically requiring connection to fixed alarm hosts or safety management platforms.

Our camping-grade CO detector focuses on carbon monoxide detection with optional CO₂ and O₂ modules. It features Bluetooth connectivity to a mobile app for real-time concentration monitoring and push alerts. CE and FCC certified, it's ideal for camping gear brands and cross-border sellers seeking custom solutions.

Pin-type (resistive) moisture meters measure wood resistance by inserting two metal pins, converting it to moisture content. They offer high accuracy (±1%) but leave pinholes on the surface, making them ideal for raw material inspection and applications where puncturing is acceptable. The MT-850 model features a measurement range of 2%~40%, a resolution of 0.5%, built-in calibration curves for multiple wood species, and automatic temperature compensation.

Inductive (electromagnetic) sensor for non-invasive, non-destructive testing. Ideal for quality spot checks on finished furniture, flooring, and surface finishes. ET-971 measures moisture content from 3% to 35%. Features one-touch calibration and support for multiple wood types.

The spherical model features a ball-shaped probe with a large contact area for stable readings, ideal for irregular surfaces and curved wood. The MT-98 accepts a replaceable 10mm electrode. Wood moisture range: 5%~75%; Building materials: 0.1%~2.4%. Displays temperature, humidity, and moisture content simultaneously on screen.

Reference ranges: indoor furniture 8%–12%; flooring 6%–9%; outdoor use 12%–15%. Furniture exported to North America is generally required to be within 6%–8% and comply with ASTM D4442.

Excess moisture causes furniture to warp, crack, or develop mold; too little makes wood brittle and prone to chipping during processing. The target value should be based on the equilibrium moisture content of the region: in humid southern areas, it can be 1–2 percentage points higher than in northern regions.

Recommended inspection frequency: Randomly sample 5%–10% of each raw material batch, conduct a quick screening every 2 hours during production, and perform 100% inspection on finished goods with records kept.

Required. Density and conductivity vary significantly across tree species; at the same moisture content, resistance values can differ by over 10%. Failing to apply species correction introduces a deviation of 1–3 percentage points.

MT-850 features built-in multi-species calibration curves, ET-971 supports switching between multiple wood types, and MT-98 provides automatic temperature compensation for synchronized temperature measurement within the -20~70°C range.

For special tree species or wood treated with preservatives, carbonization, or paint sealing, it is recommended to first perform a comparative calibration using the oven-dry method and then set instrument correction coefficients based on the results. Avoid applying standard curves directly.

AC Injection Method: Injects 1 kHz AC signal into the battery, measures voltage response to calculate internal resistance. Test time is under 1 seconds and does not affect normal battery operation, making it ideal for online inspections.

The DC discharge method measures voltage drop after a brief high-current discharge, offering higher accuracy. However, it alters the battery's operating state and is typically used for offline testing and capacity verification.

Four-wire (Kelvin) measurement separates the current path from the voltage sensing path, eliminating errors caused by lead and contact resistance. When measuring milliohm-level internal resistance, lead resistance in standard two-wire setups can exceed the value being measured, making four-wire configuration essential.

The BT-100 Battery Internal Resistance Tester uses a four-wire measurement method with an internal resistance range of 0.01 mΩ to 3000 mΩ, voltage range of 0 to 600 V. It can store up to 10000 test data sets and supports USB export.

The criterion is based on comparison with the battery's own baseline, not absolute values. A common engineering guideline: when internal resistance rises to 1.5 times the factory baseline, monitor closely; at 2 times, capacity typically drops below 80%, and replacement is recommended.

Within the same battery pack, if a single cell's internal resistance deviates more than 50% from the group average—even if the absolute value is low—it should be closely monitored. Poor consistency can degrade overall pack performance.

Recommended inspection frequency: Establish baseline data when a new battery is put into service. Inspect every 6 months for 1 years, quarterly from year 1 to 3, and monthly thereafter (after 3 years).

BT-100 supports automatic alarms for threshold exceedance. BT-200 performs constant-current discharge tests from 0 to 100A and automatically calculates capacity. Paired with PC host software, it enables trend analysis and batch management.

The BT-300 Li-ion Battery Tester supports 18650, 21700 cylindrical cells, and soft-pack (polymer) Li-ion batteries. It automatically identifies battery type and polarity to prevent damage from reverse connection.

Key Specifications: Voltage measurement 0~5 V, accuracy ±0.1%; Internal resistance measurement 0.01 mΩ~100 mΩ; Capacity test 0~20000 mAh. Equipped with an OLED display and USB-C port, powered by a built-in lithium battery. Ideal for battery manufacturing, incoming quality inspection, and recycling/sorting applications.

For testing power battery packs or higher-voltage platforms, you can choose the BT-100 (voltage range 0~600 V) or the BT-200 battery capacity tester (supports 2V/6V/12V batteries). Custom development based on customer battery specifications is also available.

Le Xin Electronic Technology (Baiantu) is a Shenzhen-based manufacturer of complete inspection and measurement instruments. Our core product lines include sound level meters, anemometers, wood moisture meters, gas detectors, and battery testers—precision instruments widely used in industrial manufacturing, environmental monitoring, construction, workplace safety, woodworking, and battery maintenance.

We offer four core business lines: standardized in-house manufacturing and direct supply, industry-specific custom solutions, ODM/OEM branded manufacturing, and full-lifecycle technical support and maintenance. Our products are widely exported to the North American market.

Fully customizable. Supports OEM/ODM customization across multiple dimensions, including housing design, logo, interface language, alarm thresholds, measurement range, and functional modules.

Please provide product specifications, intended use, quantity, and other requirements. We will evaluate your needs and provide a quote. For custom projects, we typically start with prototype validation, followed by pilot production and full-scale manufacturing.

Samples are available. Standard models are in stock and can be shipped quickly; custom models require scheduling based on the development cycle.

For specific sample policies and fees, please contact our sales team. Sample charges are typically deductible against bulk orders as agreed.

MOQ varies by product. Standard models support small-batch trial orders; OEM/ODM custom projects have higher MOQs due to mold, packaging, and production scheduling requirements.

Please share your target model and estimated quantity so we can provide the minimum order requirements and tiered pricing.

To provide an accurate quote, please include the product model or specifications, quantity, target market and certification requirements, customization needs (appearance, logo, interface, thresholds), packaging preferences, and delivery timeline.

If the model is not yet selected, please provide the application scenario and measurement target. We will assist you with model selection first.

Lead time varies by product. Standard models are in stock and ship quickly; bulk orders follow the production schedule; custom products require prototype evaluation, material procurement, and line scheduling before a lead time can be confirmed.

Export orders require additional time for certification documentation and logistics. Please confirm delivery timelines with us during the project planning phase.

We accept payment methods such as advance payments and cash. For export orders, settlement can be made via wire transfer or other agreed-upon methods. Specific payment terms are negotiable upon contract signing.

All products are certified. Every unit undergoes rigorous quality testing, individual calibration before shipment, and 72 hours of aging tests. We provide full inspection reports and certification documents. Products are CE and FCC certified.

Additionally, we can assist clients in submitting samples to third-party calibration laboratories for CNAS-accredited calibration certificates, ensuring measurement accuracy and traceability.

On-site consultations are available. Our office is located at Building A, Aoyuan Times Tech Center, Shijia Community, Matian Street, Guangming District, Shenzhen. We welcome clients from Shenzhen and surrounding areas to visit us for face-to-face technical support and business discussions. Factory floor tours and calibration process demonstrations can also be arranged upon request.

If a product has quality issues, we will assign a dedicated specialist to handle it. Shenzhen customers can receive on-site support, while customers outside the city will first undergo remote video diagnosis to identify the issue, followed by repair or replacement arrangements.

Sensor consumables (e.g., electrochemical and catalytic combustion sensors) are normal wear items. We provide replacement options and calibration support to ensure timely and effective issue resolution for our customers.