Daruifuno Launches DRH790 Digital ORP Sensor with RS485 Modbus Output
[China, November 2026] — Daruifuno has released the DRH790 digital ORP sensor, a platinum-ring oxidation-reduction potential probe with native RS485 Modbus communication, IP68 sealing and a full ±2000 mV measuring range. The new model is aimed at wastewater treatment plants, drinking water works and industrial process lines that control disinfection on ORP rather than on residual chlorine alone.
ORP, expressed in millivolts, measures the oxidising or reducing strength of water rather than its acidity. In practice it is the fastest and most stable indicator of whether a disinfectant is actually working, which is why chlorination, dechlorination, cyanide destruction and chromium reduction loops are increasingly controlled on ORP set points.
Why a Digital ORP Sensor Matters
Conventional analog ORP electrodes output a high-impedance millivolt signal that degrades over cable runs and picks up interference from variable-frequency drives, large motors and welding equipment. The DRH790 digitises the electrode potential inside the sensor body and transmits the result as a Modbus RTU register, which removes signal loss entirely and allows the probe to be installed far from the controller.
A second design decision concerns ground loops. Power supply and communication lines are electrically isolated inside the DRH790, so the measurement no longer shifts when the probe and the controller sit on different earth potentials — a common problem in plants that share a single 24 VDC supply across many instruments.
Key Specifications
| Parameter |
DRH790 |
| Measuring range |
-2000 to +2000 mV ; 0.0 to 50.0 °C |
| Resolution / accuracy |
1 mV / ±2 mV |
| Calibration modes |
Zero-point, slope and deviation calibration |
| Working pressure |
≤ 2 Bar |
| Protection grade |
IP68, continuous immersion |
| Power supply |
9 to 36 VDC, about 0.2 W |
| Communication |
RS485 MODBUS RTU |
| Body / cable |
ABS body, PUR cable 10 m standard |
| Mounting |
1" NPT thread at both ends |
| Connection options |
Bare wire, M12 plug, waterproof aviation plug |
Product Highlights
- Full span coverage. One sensor serves both oxidising duties such as chlorination and ozone, and reducing duties such as hexavalent chromium reduction.
- Three calibration modes. Zero-point, slope and deviation calibration allow fast field correction with a single ORP standard solution.
- Wide voltage input. The 9 to 36 VDC range supports 12 V battery systems, 24 V panel supplies and solar-powered remote stations.
- Five mounting methods. Side-wall, top flange, pipeline, submerged and flow-through installation are all supported by the same 1" NPT body.
- Robust cable. The polyurethane sheath resists oil, abrasion and UV, and custom lengths are available.
Target Applications
The DRH790 is intended for drinking water disinfection control, municipal and industrial wastewater effluent disinfection, cyanide destruction and sulphide oxidation, swimming pool and spa water monitoring, cooling and circulating water oxidant programmes, and oxidation or reduction bath control in electroplating, PCB, printing and dyeing, chemical, food and pharmaceutical production.
The sensor is available now with a standard 10 m PUR cable and a choice of bare wire, M12 plug or waterproof aviation plug termination. Standard ORP buffer solutions, immersion brackets and flow-through cells are offered as accessories, and OEM labelling is available for volume orders.
For technical data sheets, pricing and application support, contact the Daruifuno sales team with your process conditions including ORP range, temperature, pressure and installation method.
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