Industrial Liquid Level Sensor with Modbus RS485 Output
The PRB-LVL-RS485-101 is a submersible hydrostatic pressure probe that measures liquid level continuously and outputs the reading in millimetres over Modbus RS485 RTU. No floats. No moving parts. Just a clean, reliable level signal — ready for any Modbus-compatible gateway, PLC, or SCADA system.
How It Works
The probe is suspended into the liquid from the top of the tank using its cable. The hydrostatic pressure at the probe tip is directly proportional to the height of liquid above it. This pressure is converted to a level value in mm and transmitted digitally over RS485 using the Modbus RTU protocol — the industry standard for industrial sensor integration.
Compatible Gateways
Designed to work out of the box with:
- MOFI5A — WiFi Modbus RS485 bridge: read tank level over Wi-Fi and push to a cloud dashboard
- GLCRTU4G — 4G RTU controller: remote monitoring from locations without local network infrastructure
- Any third-party Modbus RTU master — PLC, BMS, SCADA, datalogger
Use Cases
- Overhead water storage tanks — apartment buildings, hospitals, hotels, commercial complexes
- Underground sumps — monitor fill level to trigger pump automation
- Industrial process tanks — chemicals, effluent, cooling water, wastewater
- Municipal water reservoirs — remote level telemetry for water utilities
- Agriculture and irrigation — pond and tank level monitoring
Why a Pressure Probe Over a Float Switch?
Float switches only tell you high or low. This sensor gives you a continuous reading across the full depth of the tank — so you can set precise pump-on and pump-off thresholds, catch slow leaks by tracking unexpected drops, and log level trends over time. No mechanical parts means no jamming, no corrosion, no site visits to unjam a stuck float.
Key Specifications
- Sensing principle: Hydrostatic pressure
- Output protocol: Modbus RS485 RTU
- Level output unit: mm (millimetres)
- Cable length: 5 metres (standard) — 2 m and 10 m available on request
- Installation: Submersible — cable-suspended from tank top
- Compatible liquids: Water, wastewater, chemicals (non-corrosive to probe material)
- Integration: MOFI5A, GLCRTU4G, any Modbus RTU master