会社のニュース Daruifuno Launches DPH890 Digital pH Sensor with RS485 Modbus RTU for Online Water Monitoring

Water treatment instrument manufacturer Daruifuno has introduced the DPH890, a digital pH sensor that outputs temperature-compensated pH and temperature values directly over RS485 Modbus RTU. The sensor is aimed at online monitoring points where an analog electrode plus a separate transmitter has traditionally been the only option.

The DPH890 measures 0.00~14.00 pH and 0.0~50.0 °C with 0.01 pH and 0.1 °C resolution. Accuracy is specified as 0.1% of the measuring range or ±0.02 pH, whichever is larger, with ±0.5 °C on the temperature channel. Because the high-impedance glass signal is converted inside the sensor body, the value that reaches the control system is already linearised and compensated, and cable length no longer affects the reading.

What Changed Compared with an Analog Probe

A conventional pH electrode produces a millivolt signal that must travel through a screened cable to a transmitter. In plants with pumps, mixers and variable frequency drives that signal is a known source of drift, and every additional metre of cable adds risk. The DPH890 removes that stage entirely: power and signal are electrically isolated inside the stainless steel body, and the pH and temperature values are transmitted as digital data.

• Isolated RS485 Modbus RTU output - pH at register address 2, temperature at address 4, both 32-bit floating point values.
• Automatic or manual temperature compensation, with solution-matched coefficients for natural water and pure water.
• Three-point calibration with editable buffer values, plus separate zero, slope and offset trimming.
• Selectable sampling buffer from level 2 to level 32, so response speed can be traded for noise rejection.
• IP68 stainless steel 316 and POM housing rated to 0~1 bar, with 10 m of cable as standard.

Technical Parameters

Installation and Application

Five installation variants are supported - side wall, top flange, flow-through, submerged and pipeline - which means the same sensor can be used in a tank, a channel, a bypass line or a pressurised side stream without changing model. The recommended installation angle is within ±30° of vertical, and the protection cap should stay on until commissioning is complete.

Typical duties include aeration basins and effluent channels in municipal wastewater plants, coagulation and disinfection stages in drinking water works, reverse osmosis permeate and demineralised water loops, rinse baths in electroplating and PCB lines, and reaction or CIP circuits in chemical, food and pharmaceutical production.

Documentation and Availability

Every unit ships with the DPH890 user manual, which documents the wiring colour code, the complete Modbus register map, worked command frames for reading values and calibrating, the maintenance cycle and a fault-finding table. The manual and a dimension drawing are available in advance for engineering review, so integrators can confirm wiring and protocol details before placing an order.

The sensor is available now with 10 m cable as standard and custom cable lengths on request, together with the mounting accessory set that matches the installation variant. Buyers can request the DPH890 user manual and a quotation from the manufacturer's sales engineers.