NBL-W-NS Noise Sensor with RS485 Modbus

The NBL-W-NS noise sensor is designed for continuous environmental and industrial sound-level monitoring. It measures noise levels from 30 to 130 dB over a frequency range of 31.5 Hz to 8 kHz using a 0.5-inch condenser microphone.

The sensor provides RS485 Modbus RTU communication for connection to compatible PLCs, data loggers, RTUs and IoT gateways. A 4–20mA output configuration is also available depending on the selected version.

With a 200 ms fast response, low power consumption and IP65 housing, the NBL-W-NS can be used for urban environmental monitoring, factories, construction sites, transportation, parks and other fixed noise-monitoring applications.

NBL-W-NS Noise Sensor Technical Specifications

How Does the Noise Sensor Work?

The NBL-W-NS uses a condenser microphone to detect changes in acoustic pressure. The microphone converts the incoming sound pressure into an electrical signal, which is processed by the internal electronics and converted into a noise-level measurement expressed in decibels (dB).

The instrument is intended for continuous sound-level monitoring rather than audio recording. It outputs a numerical noise measurement to the connected data-acquisition system and does not function as a voice recorder or audio surveillance device.

Noise Sensor Product Structure

The acoustic sensing section uses a 0.5-inch condenser microphone protected by the external windscreen. The slim transmitter body allows the sensor to be mounted on a pole, bracket or environmental monitoring structure.

IEC 61672 Type 2 Measurement Basis and Calibration

The NBL-W-NS specification states that its frequency weighting follows IEC 61672 Type 2 characteristics under the specified measurement conditions. The sensor is calibrated using a 94 dB reference signal over the specified frequency range, with calibration equipment such as the B&K Type 4226 multifunction sound calibrator.

For tenders, occupational-noise projects or regulatory monitoring where a specific calibration certificate, traceability requirement or independent Type 2 conformity document is required, provide the exact documentation requirement before ordering.

RS485 Modbus Noise Sensor

The RS485 version of the noise level sensor uses Modbus RTU communication and can be connected to compatible industrial controllers and remote monitoring systems.

Modbus Real-Time Noise Data

The instruction manual defines the real-time measurement request using Modbus function code 03, starting from register address 0x0000 and reading one register.

Device Address + 03 + 00 00 + 00 01 + CRC

The response contains one two-byte noise-data value in high-byte / low-byte order followed by the CRC. Use the protocol documentation supplied with the ordered sensor as the final reference for data scaling and interpretation.

RS485 vs 4–20mA Noise Sensor

Noise Sensor Wiring

For the RS485 configuration, connect the sensor according to the supplied cable identification and verify all wiring before applying power.

Noise Sensor Dimensions

The sensor has a slim cylindrical structure suitable for fixed installation on environmental monitoring equipment. The current structural drawing shows an overall length of approximately 286 mm, an acoustic windscreen section of approximately Φ80 mm and an M22 mounting connection.

Noise Sensor Installation

The sensor should be installed where the microphone is exposed to the sound environment being monitored while remaining protected from unnecessary physical obstruction, impact and unsuitable environmental conditions.

Environmental Noise Monitoring System Integration

Noise Sensor → RS485 Modbus / 4–20mA → Data Logger / PLC / RTU → 4G / Ethernet → Cloud Platform / SCADA / Private Server

The NBL-W-NS provides the local noise measurement signal. Remote 4G, Ethernet, Wi-Fi, MQTT or HTTP communication requires a compatible data logger or IoT gateway and is not built into the basic noise sensor itself.

For multi-parameter environmental monitoring, the sensor can be integrated withambient environmental sensorsfor particulate matter, temperature, humidity, CO2 and other required parameters.

What Does the Noise Sensor Measure?

The NBL-W-NS measures environmental sound level in decibels. It is intended to provide a continuous numerical noise measurement for a monitoring or control system.

Noise Sensor Applications

The NBL-W-NS environmental noise sensor is suitable for fixed monitoring projects that require continuous sound-level data rather than occasional handheld measurements.

Urban Noise Monitoring  •  Construction Sites  •  Factories & Workshops  •  Traffic Monitoring
Parks & Public Areas  •  Industrial Facilities  •  Environmental Stations  •  Building Monitoring

Fixed Noise Sensor vs Handheld Sound Level Meter

How to Select a Noise Sensor

NBL-W-NS Noise Sensor FAQ

Q1. What does the NBL-W-NS noise sensor measure?

A1. It continuously measures environmental sound level over a range of 30–130 dB and outputs the measurement to a compatible data-acquisition system.

Q2. What is the frequency range?

A2. The specified frequency range is 31.5 Hz to 8 kHz.

Q3. Does the noise sensor support RS485 Modbus?

A3. Yes. The NBL-W-NS supports RS485 Modbus RTU with a default baud rate of 9600 bps.

Q4. Is a 4–20mA version available?

A4. A 4–20mA output configuration is available depending on the selected version. Confirm the required signal type when ordering.

Q5. Does the sensor record conversations or audio?

A5. No. The sensor is designed to output numerical environmental noise-level data. It is not specified as an audio or voice recording device.

Q6. Can it be used outdoors?

A6. The current product configuration is specified as IP65 and can be used in outdoor environmental monitoring when correctly installed. Cable connections and associated electronics should also be appropriately protected.

Q7. Can several noise sensors be connected to one RS485 data logger?

A7. Yes, when the logger supports multi-device Modbus communication. Each sensor should use a unique device address, and the RS485 network should be designed with suitable power, wiring and polling intervals.

Q8. Can the sensor send data through 4G?

A8. Yes, by connecting the RS485 sensor to a compatible 4G data logger or IoT gateway. Cellular communication is not built into the basic NBL-W-NS sensor.

Q9. Can it be used for regulatory environmental-noise monitoring?

A9. The product specification references IEC 61672 Type 2 frequency-weighting characteristics. Regulatory projects may have additional requirements for calibration, certification, installation and reporting, so those requirements should be confirmed before selection.

Q10. What information is required for a quotation?

A10. Provide the quantity, application, required RS485 or 4–20mA output, installation environment, cable requirements, data logger or PLC model, communication requirements and any required calibration or tender documentation.

NBL-W-NS Noise Sensor Instruction Manual

NBL-W-NS-Noise-Sensor-Instruction-Manual.pdf

Request an NBL-W-NS Noise Sensor Quotation

For model selection and quotation, provide the application, quantity, required RS485 or 4–20mA output, installation environment, cable requirement and receiving data logger, PLC or RTU.

For environmental monitoring projects, also specify whether you require PM2.5 / PM10, temperature and humidity, CO2, a data logger, 4G communication, cloud monitoring or private-server integration so the complete monitoring system can be configured.