Detect and report low turbidity (0-50 NTU, 0.01 NTU resolution) in water tanks

Turbidity Sensor — Modbus RS485, IP68, 0–4000 NTU

The PRB-TUR-RS485-101 is a submersible turbidity probe that measures water clarity and outputs readings over Modbus RS485 RTU. IP68-rated for continuous immersion, with a fast 1-second response time and a measurement range of 0–4000 NTU covering drinking water, raw surface water, industrial effluent, and sludge applications. Light source at 860 nm minimises colour interference.

What Is Turbidity?

Turbidity is the cloudiness of water caused by suspended particles — sediment, algae, organic matter, or industrial solids. It is a primary indicator of water quality: low turbidity in treated water confirms effective filtration; elevated turbidity in a river after rain signals runoff contamination; rising turbidity in a process tank can indicate a filter failure or a process upset. Continuous turbidity monitoring enables early intervention before water quality standards are breached.

Measurement Ranges

Compatible Gateways

• MOFI5A — WiFi Modbus RS485 bridge: cloud dashboard over WiFi
• GLCRTU4G — 4G RTU: remote monitoring without local network infrastructure
• Any Modbus RTU master — PLC, SCADA, datalogger, water treatment control system

Use Cases

• Municipal water treatment plants — filter breakthrough detection, treated water quality verification
• Surface water intake monitoring — river and reservoir turbidity after rain events
• Effluent discharge compliance — continuous turbidity logging at outfall for regulatory reporting
• Swimming pools and aquariums — water clarity monitoring for safety and aesthetics
• Industrial process water — in-line monitoring of cooling water and rinse water quality
• Sludge and mining operations — high-range turbidity tracking in heavy-sediment applications

Key Specifications

• Parameter: Turbidity (NTU)
• Measurement ranges: 0–100, 0–1,000, or 0–4,000 NTU (range-selectable)
• Accuracy: ±5% or ±3 NTU (low range); ±3% or ±2 NTU (higher ranges)
• Resolution: 1 NTU
• Light source: 860 nm infrared — minimises colour interference
• Response time: ≤1 second
• Output: Modbus RS485 RTU
• Power supply: 12–24V DC, <0.15W
• Installation: Immersive (submersible)
• Working pressure: 0–0.2 MPa (up to 20 m water depth)
• Protection: IP68
• Working temperature: 0–50°C

Installation and Maintenance

• Suspend the probe in the water column at the desired monitoring depth
• Clean the optical window every 30 days to prevent biofilm or sediment buildup from affecting readings
• Avoid contact with organic solvents, oils, or high-concentration gases during cleaning
• Store the sensor clean and dry when not deployed