SMART WiO – Water in Oil Sensor

The SMART WIO is a water in oil sensor measuring the humidity providing a key indicator of oil quality

Overwiew

Using the SMART WIO water-in oil sensor in oil condition monitoring systems, ensures optimal engine performance while protecting against potential damage caused by excess water content.

The SMART WiO (Water-In-Oil) Sensor measures the absolute water content in oil—not the free water or emulsion that is detectable by standard water in oil test kits. This advanced oil condition sensor utilises a capacitive measurement technique that operates on the principle of water absorption in oil, providing a physical measured value expressed as % Humidity.

New oil can hold a specific amount of dissolved water, known as the “saturation point.” If this limit is exceeded, free water may separate, potentially causing corrosion within the engine. The saturation point is influenced by temperature and other factors such as the type of oil (mineral or synthetic) and additive formulations, and can change throughout the oil’s lifecycle.

The PAV (Pre Alarm Value) is calibrated to 50% humidity, while the MAV (Main Alarm Value) is set at 90% humidity. Should humidity exceed 100%, it indicates the presence of free water. If the WiO Water-in-oil Sensor raises an alert, indicating humidity above 90%, it signals potential damage as conditions approach the saturation point.

Applications

Oil condition monitoring system for lubrication oils including:

  • 2 and 4 Stroke Engines
  • Compressors
  • Pumps
  • Gearboxes
  • Turbines

Condition monitoring for hydraulic oils including all machines using hydraulic oil up to 10 bar

Technical Specifications

 

MEASUREMENT
Power Supply 18…32 VDC
Current Consumption 60mA
Polarity Protection Yes
Alarm relays
    • Pre-alarm at 50% humidity
    • Main alarm at 90% humidity
Output Current <300mA
Operating Temperature -25 to +85 0C
Protection Degree IP67
Analog Output: Water in Oil 4…20 mA (equiv. 0…100% Humidity Linear)
Analog Output: Temperature 4…20 mA (equiv. 0…1000C Linear)
Dimensions 125mm x 80mm x 57mm
Local Indication LED Indicators
Sensor Probe Specification
Wrong Polarity Protection Yes
Operating temperature -25 to 85 deg C
Protection degree IP65
Pressure resistance against medium 10 bar
Connection type G3/4” Male Thread
Material Stainless Steel AISI 303; 1.4305
Dimensions 50mm x 187mm
Cable Length to Controller 15m
Insertion Length 120mm
Local indication LED Indicators