This product uses a high-quality electret condenser microphone as the acoustic-to-electric conversion device, featuring high sensitivity, flat frequency response, and strong anti-interference capability. With a built-in high-precision ADC and DSP algorithm, it collects ambient noise in real-time and calculates parameters such as equivalent continuous sound pressure level (Leq) and maximum sound pressure level (Lmax). Data is aggregated and transmitted via RS485 bus using the MODBUS-RTU protocol, widely applicable to factory workshops, school classrooms, traffic noise monitoring, smart cities, and environmental noise online monitoring systems.
Key Advantages Electret condenser moisture resistance | Wide voltage 5-24V supply | Data aggregation upload | RS485 long-distance networking | A/C frequency weighting support
| Parameter | Specification |
|---|---|
| Sensor Type | Electret Condenser Microphone (back-electret type) |
| Measurement Range | 30 dB ~ 130 dB (auto-ranging) |
| Frequency Range | 20 Hz ~ 12.5 kHz |
| Frequency Weighting | A-weighting (default), C-weighting / Z-weighting (configurable) |
| Time Weighting | Fast (125ms) / Slow (1s) selectable |
| Measurement Accuracy | ±1.5 dB (@ 94dB, 1kHz reference) |
| Resolution | 0.1 dB |
| Response Time | ≤ 1 second (continuous refresh) |
| Supply Voltage | 5.0 ~ 24 VDC (12V or 24V recommended) |
| Power Consumption | ≤ 0.3W (≤ 25mA @ 12V) |
| Communication Interface | RS485 (half-duplex) |
| Communication Protocol | MODBUS RTU |
| Baud Rate | 9600 (default, supports 4800/19200/38400) |
| Data Format | 8N1 (8 data bits, no parity, 1 stop bit) |
| Device Address | 1~247 (default 1) |
| Operating Environment | -20℃ ~ +60℃, 10%~95%RH (non-condensing) |
| Protection Rating | IP54 (windshield available for outdoor use) |
| Dimensions | 98×52×30 mm (including mounting ears) |
| Label | Description | Wiring Recommendation |
|---|---|---|
| VCC | Power Positive (5~24V DC) | Connect to DC regulated power supply positive (5V/12V/24V) |
| GND | Power Ground / Signal Ground | Connect to power negative, also serves as RS485 reference ground |
| 485A+ | RS485 A+ (non-inverting) | Connect to host (PLC/DAQ) A+ terminal |
| 485B- | RS485 B- (inverting) | Connect to host B- terminal |
The electret condenser microphone is built into the front of the sensor, equipped with a windproof foam/metal protective mesh. During installation, aim the microphone toward the noise source, avoiding direct facing of high-speed airflow or ducts. For outdoor environments, it is recommended to add a rain cover and windscreen.
The device calculates noise sound pressure levels in real-time and updates the results to internal registers. The host can read via function codes 03 or 04. Supports multi-sensor networking. All noise data is aggregated and uploaded to the monitoring center or cloud platform via RS485.
| Register Address (HEX) | Parameter Name | Data Type | Description / Conversion |
|---|---|---|---|
| 0x0000 | Equivalent Continuous Level Leq (dB) | 16-bit unsigned integer | Unit: 0.1dB, actual value = register value ÷ 10 Example: 0x03E8 = 1000 → 100.0 dB |
| 0x0001 | Maximum Level Lmax (dB) | 16-bit unsigned integer | Unit: 0.1dB, same as above |
| 0x0002 | Minimum Level Lmin (dB) | 16-bit unsigned integer | Unit: 0.1dB |
| 0x0100 | MODBUS Address | 16-bit | 1~247, default 1 (supports function code 06 modification) |
| 0x0101 | Baud Rate | 16-bit | 0:9600, 1:4800, 2:19200, 3:38400 |
| 0x0102 | Frequency Weighting | 16-bit | 0:A-weighting, 1:C-weighting, 2:Z-weighting |
The device refreshes noise data at a rate of once per second and stores it in the register area. The host polls each sensor address via the RS485 bus to obtain multi-point noise data. All aggregated data can be used to present regional noise distribution maps or real-time curves.
| Phenomenon | Possible Cause | Solution |
|---|---|---|
| Abnormal readings (too low or 0dB) | Insufficient power, microphone clogged or damaged | Check power supply voltage, clean windscreen; gently blow on microphone to see value change |
| Severe data fluctuation | Strong wind noise or electromagnetic interference | Add windscreen, use shielded twisted-pair cable for RS485 |
| No communication | Address/baud rate mismatch, wiring error | Verify A/B connections, try resetting device address |
| Consistently high readings | Incorrect weighting or calibration drift | Check frequency weighting register, restore factory settings |
| Unstable RS485 communication | Missing termination resistor, excessive distance | Add 120Ω termination resistors at both ends, reduce baud rate |
It is recommended to calibrate the sensor every 12 months using a sound level calibrator (94dB@1kHz). Users can perform gain correction through manufacturer-specific MODBUS commands or software. For daily cleaning, use a soft brush to gently remove dust from the electret microphone surface. Do not use organic solvents.
| Ordering Model | Description | Power Supply Range | Output |
|---|---|---|---|
| YTL-NS-EM-RS485 | Electret Condenser Noise Sensor, A/C weighting configurable | 5~24V DC | RS485 MODBUS |
| YTL-NS-EM-PRO | Enhanced version with temperature/humidity compensation and windscreen | 12~24V DC | RS485 + Temp/Humidity |
Up to 128 noise sensors can be connected via the RS485 bus, each with a unique address. The host (industrial computer/data collector) polls each sensor and aggregates Leq, Lmax and other data, ultimately uploading to environmental protection platforms or cloud monitoring systems via Ethernet/4G.