The ERUN-SZ4-A-B7B is a CE, RoHS, and ISO 9001 certified online pH analyzer with RS485 Modbus communication, integrated temperature compensation, and IP68-rated submersible design—delivering reliable 24/7 pH monitoring for industrial wastewater, water treatment, and chemical processing applications.
The global online pH analyzer market was valued at US$4,442 million in 2025 and is projected to reach US$7,813 million by 2032, growing at a CAGR of 8.4%. As industries worldwide demand more precise, digitally integrated water quality monitoring solutions, the ERUN-SZ4-A-B7B meets this need with a digital sensor architecture that integrates signal conditioning directly inside the sensor body—eliminating the signal degradation issues common with analog pH probes.
What Makes the ERUN-SZ4-A-B7B Different from Traditional pH Analyzers?
The ERUN-SZ4-A-B7B is a digital pH analyzer with built-in signal processing, RS485 Modbus RTU communication, and dual 4-20mA output—allowing direct integration with PLC, DCS, and SCADA systems without requiring a separate transmitter.
Unlike conventional analog pH sensors that transmit raw millivolt signals over long cable runs—making them susceptible to electromagnetic interference and signal drift—this digital sensor digitizes the measurement at the source. The result is stable, noise-free data transmission even in electrically noisy industrial environments. Power supply and output circuits are isolated by design, ensuring signal integrity.
What Certifications Does the ERUN-SZ4-A-B7B Hold for Global Export?
The ERUN-SZ4-A-B7B carries CE marking (EU conformity), RoHS compliance (hazardous substance restriction), and ISO 9001 certification (manufacturing quality management)—three credentials that collectively enable market access across the EU, North America, and other regulated regions.
CE certification confirms the product meets EU safety, health, and environmental protection standards. RoHS compliance ensures the sensor is free from restricted hazardous substances, a requirement for electronics sold in the EU and many other markets. ISO 9001 certification verifies that manufacturing processes adhere to internationally recognized quality management standards. These certifications are not merely badges—they are documented proof that the ERUN-SZ4-A-B7B meets the regulatory requirements of major global markets.
What Are the Key Technical Specifications?
Parameter | Specification |
|---|
Power Supply | DC 9–28V |
Power Consumption | 0.5W |
Measurement | pH + Temperature |
Communication | RS485 + 4-20mA dual output |
Protocol | Modbus-RTU |
Operating Temperature | -5°C to 45°C (non-freezing) |
Pressure Rating | <0.1MPa |
Housing Material | POM plastic |
Protection Rating | IP68 (submersible) |
pH Range | 0–14 pH |
pH Accuracy | ±0.05 pH |
pH Resolution | 0.01 pH |
Temperature Range | -5°C to 60°C |
Temperature Accuracy | ±0.4°C |
Temperature Compensation | Built-in automatic |
The sensor measures pH via the electrochemical (electrode) method and temperature via thermistor, with a pH response time (T90) of ≤60 seconds and temperature response time of ≤25 seconds. Calibration options include single-point, two-point, or three-point calibration for pH, and single-point calibration for temperature.
Why Choose a Digital pH Sensor with RS485 Modbus?
RS485 Modbus is the industry-standard communication protocol for industrial automation—it enables daisy-chaining multiple sensors on a single bus, reduces wiring complexity, and allows seamless integration with existing PLC and SCADA infrastructure.
The ERUN-SZ4-A-B7B combines RS485 Modbus RTU with a 4-20mA analog output, giving engineers flexibility to connect to both modern digital control systems and legacy analog equipment. This dual-output design means you can deploy the sensor in new installations or retrofit it into existing monitoring networks without changing your control infrastructure. The Modbus protocol also enables two-way communication—not just reading pH values, but also configuring parameters and diagnostics remotely.
Where Is the ERUN-SZ4-A-B7B Online pH Analyzer Used?
This pH analyzer is designed for continuous, real-time pH monitoring in industrial wastewater treatment, municipal water supply, chemical processing, power generation, pharmaceutical manufacturing, and environmental monitoring applications.
With its IP68 protection rating, the sensor can be submerged in water for extended periods without damage, making it suitable for tank immersion, pipe installation, and open-channel monitoring. The POM plastic housing provides corrosion resistance in chemically aggressive environments, while the compact form factor (206mm × φ32 for clamp type; 226mm × φ32 for G3/4 thread) allows installation in space-constrained systems.
FAQ
Q: What is the difference between a digital and analog pH sensor?A: A digital pH sensor converts the pH signal to digital data inside the sensor body and transmits it via digital protocols like RS485 Modbus. This eliminates signal loss and interference over long cable runs, whereas analog sensors transmit raw millivolt signals that degrade with cable length.
Q: Does the ERUN-SZ4-A-B7B require a separate controller or transmitter?A: No. The digital electronics are built into the sensor itself. It outputs RS485 Modbus and 4-20mA signals directly, so it can connect to PLC, DCS, SCADA, or data loggers without an external transmitter.
Q: What is the calibration procedure?A: The sensor supports single-point, two-point, or three-point calibration using standard pH buffer solutions. Temperature calibration is single-point.
Q: Can this sensor be used in seawater or high-salinity water?A: Yes, the sensor is suitable for seawater and other saline water applications, with the POM housing providing corrosion resistance.
Q: What is the lifespan of the pH electrode?A: Electrode lifespan depends on application conditions and maintenance frequency. Regular cleaning and calibration extend operational life. The replaceable electrode design minimizes replacement costs.
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For over a decade, Xi’an Erun Environmental Protection Technology Group has been delivering precision analytical instruments to clients across Singapore, France, Indonesia, India, Chile, the DRC, Vietnam, and beyond—backed by 100+ patents, 90+ software copyrights, and a commitment to innovation that protects both ecological and industrial safety.
