Residual Chlorine Sensor — Modbus RS485, Water Quality Monitoring
The PRB-CL-RS485-201 is an industrial-grade residual chlorine probe that measures free chlorine concentration in water and outputs the reading over Modbus RS485 RTU. Non-membrane, reagent-free design based on constant-voltage electrochemical sensing with a high-purity platinum electrode. Integrates directly with Ahoy IoT gateways, PLCs, SCADA systems, and any Modbus master.
Non-Membrane, Reagent-Free Design
Traditional chlorine analysers use membranes and chemical reagents that need frequent replacement and recalibration. This probe uses constant-voltage electrochemical technology with a platinum electrode — no membrane to replace, no reagents to replenish. Maintenance is limited to periodic electrode cleaning. Built for continuous, unattended operation.
Integrated Temperature Compensation
Chlorine solubility and electrochemical response vary with water temperature. The probe includes a built-in temperature sensor and automatically compensates readings — ensuring accurate chlorine values regardless of water temperature variations.
Compatible Gateways
- MOFI5A — WiFi Modbus RS485 bridge: monitor chlorine levels on a cloud dashboard over WiFi
- GLCRTU4G — 4G RTU: remote monitoring in locations without local network infrastructure
- Any third-party Modbus RTU master — PLC, BMS, SCADA, water treatment SCADA
Use Cases
- Municipal water distribution networks — residual chlorine monitoring at distribution points and service reservoirs
- Apartment and building water storage tanks — verify adequate disinfection at point of use
- Swimming pools and recreational water — automated chlorine dosing feedback
- Food and beverage processing — sanitisation water quality verification
- Cooling towers — legionella prevention through chlorine level monitoring
- Wastewater treatment — effluent disinfection compliance monitoring
Key Specifications
- Parameter: Free residual chlorine
- Sensing technology: Constant-voltage electrochemical — high-purity platinum electrode
- Measurement range: 0–20 mg/L, resolution 0.01 mg/L
- Accuracy: ±5% FS (RS485) / ±3% FS (analogue outputs)
- Output: Modbus RS485 RTU (also 4–20 mA, 0–5V, 0–10V analogue outputs available)
- Power supply: DC 10–30V
- Installation: 3/4-inch standard thread — immersive or flow-cell mounting
- Maintenance: Periodic electrode cleaning only — no reagents or membrane replacement