Nexisense 4-in-1 Gas Sensor: The Preferred Multi-Gas Safety Monitoring Solution for System Integrators

In high-risk industrial scenarios such as petrochemical plants, underground utility tunnels, wastewater treatment facilities, firefighting and emergency response, and hazardous chemical storage, single-gas monitoring can no longer meet the real-time multi-parameter monitoring requirements of modern Safety Instrumented Systems (SIS) and Distributed Control Systems (DCS). The Nexisense 4-in-1 gas sensor module (TZHCO-01B series) integrates combustible gas (LEL), oxygen (O₂), carbon monoxide (CO), and hydrogen sulfide (H₂S) into a single device. With industrial-grade reliability and system compatibility, it provides system integrators, IoT solution providers, and EPC contractors with an efficient and cost-effective multi-gas monitoring solution.

This article analyzes the technical characteristics, typical project applications, selection guidelines, and key integration considerations of the Nexisense 4-in-1 sensor from the perspective of system integration, helping B2B procurement decision-makers and project managers more clearly evaluate its value in real-world engineering projects.

Core Technologies and Engineering Advantages of the 4-in-1 Gas Sensor

• IP66 protection rating, suitable for complex industrial environments with high humidity, dust, and corrosive gases

• Built-in intelligent temperature and humidity compensation algorithms to effectively suppress environmental drift

• Supports triple alarm outputs (sound + light + vibration), and provides relay, dry contact, and digital signal outputs

• Rich communication interfaces: RS-485 (Modbus RTU), 4-20mA, UART, I2C (optional)

• Mean Time Between Failures (MTBF) > 5 years; sensor element design life ≥ 3 years (CO/H₂S) / ≥ 5 years (O₂/LEL)

• Wide operating temperature range: -40°C to +70°C, suitable for most outdoor and semi-outdoor installation scenarios

  
  

Typical Project Application Scenarios from a System Integration Perspective

Petrochemical and Hazardous Chemical Storage Safety Monitoring Systems

In refining enterprises, hazardous chemical warehouses, and LNG receiving stations, 4-in-1 sensors are commonly deployed in key explosion-proof areas such as pump areas, tank farms, and loading/unloading zones. The Nexisense module connects to explosion-proof data acquisition modules via RS-485 bus, supporting multi-point networking (32–128 nodes per bus), with real-time data uploaded to the Safety Instrumented System (SIS) or central control room.
Real Case: In a tank farm upgrade project at a medium-sized refining enterprise, the integrator replaced the original split-type detectors with Nexisense 4-in-1 modules and connected them to a SIL2-rated safety PLC. Seamless integration with the existing ESD system was achieved via Modbus RTU protocol, reducing system response time from 8–12 seconds to 3–5 seconds and decreasing false alarm rate by approximately 65%.

Underground Utility Tunnels and Municipal Tunnel Monitoring

Underground utility tunnel projects have extremely high requirements for waterproofing, dustproofing, and corrosion resistance, while needing to monitor multiple gases to prevent oxygen deficiency, toxic gas accumulation, and combustible gas leaks. The Nexisense IP66-rated module can be directly installed on tunnel brackets or wall-mounted explosion-proof junction boxes, with signals connected to the comprehensive tunnel monitoring platform via 4-20mA or RS-485.
Case Reference: In an East China urban utility tunnel PPP project, the system integrator deployed points in the power, communication, and gas cabins, using Nexisense 4-in-1 modules to achieve full-section gas monitoring. Data is uploaded to a cloud platform via LoRa+4G gateways, supporting remote threshold configuration and historical trend analysis, significantly improving the operator’s emergency response capability.

Wastewater Treatment Plants and Sludge Processing Areas

Aeration tanks, anaerobic tanks, and sludge dewatering workshops are high-risk areas for H₂S and oxygen deficiency. The Nexisense module can be integrated into the plant’s DCS or PLC system, with relay outputs directly linked to fans, aeration valves, or sound-light alarms.
Project Practice: In the Phase II expansion of a large wastewater treatment plant in southern China, the integrator connected the 4-in-1 sensors to the existing SCADA system, implementing a three-level protection strategy of “local alarm + remote upload + interlock control,” effectively reducing the exposure risk to operators.

Firefighting Emergency and Mobile Monitoring Solutions

Firefighting rescue vehicles, emergency monitoring vehicles, and petrochemical inspection robots often require portable or semi-fixed multi-gas detection equipment. The Nexisense module supports low-power design and UART/I2C interfaces, making it suitable for integration into embedded controllers or industrial tablet computers.

4-in-1 Gas Sensor Selection Guide

1. Gas Type and Range Matching: Confirm the specific gas combination and concentration range required by the project to avoid resolution waste or insufficient range due to oversized or undersized specifications.

2. Output Signal and Communication Protocol:

• For traditional PLC/DCS systems: Prefer 4-20mA + RS-485 (Modbus RTU)

• For IoT/edge computing solutions: Prefer UART/I2C + RS-485

• For direct linkage to actuators: Choose models with relay output

3. Installation Environment and Protection Requirements: High humidity/corrosive gases → IP66 required; Explosion-hazardous areas → Confirm whether Ex d IIC T6 Gb or higher explosion-proof rating is needed

4. Power Supply Type and Consumption: Fixed installation: Standard 24VDC; Mobile/portable scenarios: Prefer low-power version (<1.5W)

5. Calibration and Maintenance Cycle: For projects with limited maintenance capability, prioritize models supporting on-site zero/span calibration and evaluate spare parts inventory strategy.

It is recommended to request the complete Technical Data Sheet (TDS) and 3D model files during the proposal stage for early design and pipeline reservation.

Key Considerations in System Integration Engineering

• EMC and Grounding: RS-485 bus should use shielded twisted-pair cable with single-end grounding to avoid ground loop interference.

• Explosion-Proof Safety Design: When installing in explosion-hazardous areas, connection must be made through intrinsic safety barriers or explosion-proof junction boxes, ensuring the entire loop complies with explosion-proof standards.

• Signal Isolation and Surge Protection: For outdoor or long-distance transmission, install signal isolators and surge protectors to safeguard the module and host system.

• Alarm Logic and Interlock Strategy: Implement multi-level alarm logic (warning–alarm–interlock) in PLC or edge controllers to avoid production shutdowns caused by single-sensor false triggers.

• Long-Term Drift Management: Establish regular on-site calibration (recommended every 6–12 months) or use intelligent diagnostics for predictive maintenance.

• Software Integration Testing: Before commissioning, perform complete communication testing, alarm verification, and power-off/restart testing to ensure system robustness.

  
  

FAQ – Frequently Asked Questions

1. What mainstream communication protocols does the Nexisense 4-in-1 module support? It supports Modbus RTU (RS-485), 4-20mA, UART, and I2C, with selection or customization available based on project needs.

2. Is additional certification required when using it in explosion-proof areas? The module body can provide Ex d IIC T6 Gb explosion-proof certification. During integration, the entire loop must comply with site explosion-proof requirements.

3. How to handle long-term drift of the H₂S sensor after prolonged exposure? Combine built-in temperature compensation with regular on-site calibration—full-range calibration is typically recommended every 6–12 months.

4. Can it connect directly to LoRaWAN or NB-IoT gateways? Yes. It has been successfully integrated via UART/RS-485 interfaces with third-party gateways in multiple utility tunnel and petrochemical projects.

5. How much cost can a 4-in-1 module save compared to four separate sensors? Total procurement, installation, wiring, and maintenance costs can usually be reduced by 60%–75%, depending on project scale and point density.

6. Can the module’s operating temperature range meet outdoor use in northern winter? Standard operating range is -40°C to +70°C, suitable for outdoor installation in most regions of China.

7. Is OEM/ODM customization service available? Yes, including enclosure, interface, range, communication protocol, brand logo, etc. Minimum order quantity is negotiable.

8. How to obtain complete technical documentation and samples? You can apply for TDS, 3D models, sample testing, and project solution support through the official website, technical support email, or business channels.

Summary

With multi-gas integration, high protection rating, rich interfaces, and long-term reliability as its core strengths, the Nexisense 4-in-1 gas sensor provides system integrators and engineering companies with a balanced solution that combines performance and cost-effectiveness. Whether for new projects or brownfield upgrades, it effectively reduces the number of detection points, simplifies system architecture, and improves safety compliance.

If you are currently advancing safety monitoring projects in petrochemical, utility tunnels, wastewater treatment, hazardous chemical storage, or firefighting emergency applications, we welcome you to contact the Nexisense technical and business team. We will provide targeted selection advice, integration guidance, and sample support based on your specific site conditions, control system architecture, and budget to help ensure safe and efficient project implementation.