Industrial TDS Sensor for Water Tanks — Modbus RS485
The PRB-TDS-RS485-101 is a submersible water quality probe that measures Total Dissolved Solids (TDS), electrical conductivity (EC), salinity, and temperature simultaneously — all delivered over Modbus RS485 RTU. One probe, four parameters, zero reagents.
What It Measures
TDS is a key indicator of water purity. High TDS signals contamination, mineral buildup, or RO membrane failure. This probe measures TDS continuously using an EC electrode with automatic temperature compensation, so readings stay accurate regardless of water temperature.
- TDS — 0 to 1,100 ppm (K=1 model) or 0 to 13,400 ppm (K=10 model)
- Electrical Conductivity (EC) — 1 to 2,000 μS/cm or 10 to 20,000 μS/cm
- Salinity — 0 to 1,000 ppm
- Temperature — -5°C to +80°C (±0.5°C), used for auto compensation
Use Cases
- Drinking water tanks — monitor TDS to verify RO output quality and trigger filter replacement alerts
- Apartment and commercial buildings — automated water quality logging without manual testing
- Industrial process water — boiler feed water, cooling towers, chemical dilution tanks
- Aquaculture — salinity and EC monitoring in fish or prawn tanks
- Wastewater / STP — inlet and outlet TDS comparison for treatment efficiency tracking
Compatible Gateways
- MOFI5A — WiFi Modbus RS485 bridge: push TDS readings to cloud over Wi-Fi
- GLCRTU4G — 4G RTU: remote monitoring without local network infrastructure
- Any third-party Modbus RTU master — PLC, BMS, SCADA, datalogger
Key Specifications
- Output protocol: Modbus RS485 RTU
- TDS range: 0–1,100 ppm (K=1) / 0–13,400 ppm (K=10)
- EC accuracy: ±1% FS with automatic temperature compensation
- Power supply: DC 10–30V, 0.4W
- Protection: IP68 — fully submersible
- Cable length: 5 metres standard (2 m and 10 m available on request)
- Integration: MOFI5A, GLCRTU4G, any Modbus RTU master