Sensor specifications
Why aw rather than ppm
ppm does not tell you how close you are
The same ppm water content sits at a completely different distance from saturation depending on oil temperature and oil type. ppm is an absolute quantity that still has to be converted before it means anything for risk.
aw reflects saturation directly
Water activity from 0 to 1 aw states directly how close the oil is to saturation; approaching 1 means free water is about to separate. It reads meaningfully without first knowing the oil temperature or type.
Free water is what does the damage
Dissolved water does limited harm. Once it separates as free water it seriously degrades the lubricating film and insulating performance — which is exactly why warning before separation is worth having.
Analog and digital output together
4–20 mA analog output and Modbus RTU over RS-485 are both provided, with a relay output option. An older plant whose PLC only accepts 4–20 mA can wire straight in, while a newer monitoring system reads values and status over Modbus — no need to change model because the integration method differs. Measurement range is 0 to 1 aw with ±0.05 aw accuracy, over an operating range of −40 to 125 °C.
Oil resistant, pressure resistant, serviceable
A stainless steel probe with IP66 protection is immersed directly in the oil line. The modular design means service replaces a module rather than scrapping the whole unit. Every unit is rigorously calibrated before shipping — water activity measurement demands consistent sensing elements, and calibration quality decides directly whether a field reading can be trusted.
Wondering whether your oil line suits online monitoring?
Tell us the oil type, operating temperature, line pressure and mounting position, and we will recommend an installation method and output interface.