PH-110 Industrial pH Probe - RS485 + Analog Output

Overview

The PH-110 is an industrial pH probe designed for continuous water quality measurement and control. It combines RS485 Modbus RTU with multiple analog output options (0-2V, 0-5V, 0-10V, 4-20mA) so the same sensor drops into both modern IoT controllers and legacy PLC or SCADA panels. Internal axial capacitor filtering, 100MΩ high-impedance front end, and four-layer isolation give it the noise immunity needed for greenhouses, sewage plants, and chemical process water.

Key Features

• Dual Output: RS485 Modbus RTU plus analog (0-2V, 0-5V, 0-10V, or 4-20mA) on the same probe
• Four-Layer Isolation: Robust interference rejection in electrically noisy environments
• High-Impedance Front End: 100MΩ input for stable, low-noise pH measurement
• Three-Point Calibration: 4.00, 6.86, and 9.18 pH buffer points via Modbus commands
• IP68 Waterproof: Continuous immersion rated, suitable for tanks, channels, and basins
• Industrial Mount: 3/4” NPT thread for direct insertion in pipes and process vessels
• Compact Form: 175mm total length, 28mm probe diameter
• Low Power: ≤0.5W consumption, runs on standard 7-24 VDC supply

Applications

• Greenhouse and hydroponic nutrient control
• Agricultural irrigation pH monitoring
• Aquaculture and recirculating aquaculture systems (RAS)
• Sewage and wastewater treatment plants
• Chemical industry process water
• Environmental water quality monitoring
• Drinking water treatment
• General industrial pH control loops

Technical Specifications

The PH-110 measures across the full 0 to 14.00 pH range with 0.01 pH resolution and ±0.02 pH accuracy. Stability is specified at ≤0.02 pH drift per 24 hours under stable conditions, which keeps calibration cycles reasonable in continuous deployments.

The probe operates from 0 to 70°C and tolerates up to 85% relative humidity. Total power consumption stays at or below 0.5W.

Connectivity and Integration

The PH-110 exposes both digital and analog interfaces on the same probe:

• RS485 Modbus RTU: 9600 bps, 8N1, default address 0x01. Reads the pH value from register 0x0000 (scaled by 100). Calibration commands write to registers 0x005A, 0x005B, and 0x005C for the three buffer points.
• Analog Voltage: 0-2V (pH = V × 7), 0-5V (pH = V × 2.8), or 0-10V (pH = V × 1.4)
• Analog Current: 4-20mA (pH = (mA - 4) × 0.875)

Wire the RS485 interface with red (V+), black (GND), yellow (RS485-A), and green (RS485-B). For analog output, red and black carry power while yellow and green carry the signal pair.

Why Choose Industrial-Grade pH Sensing

The PH-110 is built for installations where the controller may not always be a modern IoT device. Sites running mixed equipment, with a legacy PLC reading 4-20mA on one loop and a cellular gateway reading Modbus on another, can use a single sensor model across both. Four-layer isolation and 100MΩ input impedance give it the headroom to stay accurate next to pumps, VFDs, and dosing solenoids that would degrade a less protected probe.

Installation Notes

The 3/4” NPT thread mounts directly into pipe tees, tank ports, and process bypass loops. The probe head should be fully submerged with the sensing element facing the flow direction, away from dead zones and air pockets. Avoid hot-plugging the connector and verify wiring before powering up. Rinse with distilled water between calibration buffers, and never touch the sensing membrane with sharp objects or oily surfaces.

Compatibility with Agrinovo Controllers

The PH-110 connects natively to all Agrinovo Genesis controllers via RS485 Modbus. Analog outputs are also fully supported on the analog input ports of the Genesis Lite and Exodus controllers, making this probe a flexible choice across the full Agrinovo lineup.

Related Guide: Aquaculture Water Quality Monitoring: Complete Sensor Guide