Moisture Content Sensor

Water in hydraulic and lubrication fluids is one of the main causes of oxidation, additive depletion, loss of dielectric strength in insulating oils, corrosion, and reduced lubricating film thickness. These expensive problems can be prevented by monitoring the water level of your fluid and taking action at an early stage.



The moisture content sensor (MCS) is suitable for most hydraulic and lubricating fluids. The high accuracy of the measurement and excellent long-term stability make the MCS ideal for online monitoring of moisture in transformer, lubricating and hydraulic fluid, as well as diesel fuel. The MCS is perfectly suitable for long term usage in moisture levels, higher than 90% relative humidity. Making it the perfect solution for gearboxes, thrusters, and other applications where free water is a threat. By combining the MCS with other oil monitoring products like a Condition Monitoring Center and vacuum dehydration unit, we offer you the optimal solution for your water contamination problems.

The compact design and rugged stainless steel housing allow a space-saving installation in the most demanding applications. The MCS measures water activity and oil temperature. The measured values are available on two 4-20mA outputs and one digital output with MODBUS RTU interface and can be integrated with our Condmaster Ruby vibration monitoring software.

Typical applications

– Transformer oil
– Lubrication oil
– Hydraulic oil
– Engine oil
– Diesel fuel



Supply voltage                                     24 VDC
Power consumption at 24V DC       <40mA
Pressure rating                                    0...20 bar (0...290 psi)
Measurement range                          0 -100% RH
Housing/protection rating             Stainless steel 1.4404 / IP65
Connection                                          G1/2’’ BSP
Electrical connection                         M12 8-pin plug
Sensor protection                               Stainless steel filter
Oil temperature                                  -40...100 °C (-40...212 °F)
Ambient temperature                       -40...80 °C (-40...176 °F)
Storage temperature                        -40...60 °C (-40...140 °F)
Electromagnetic compatibility      EN61326-1 EN61326-2-3
Industrial environment
Fluid compatibility                            Petroleum-based and synthetic fluids

2 x analogue output                         4 - 20 mA (3-wire technology) <500 Ohm
Digital output                                     MODBUS RTU

Humidity sensor                              ± 2% 0 to 90% & ±3% 90 to 100%
Temperature in oil                           ±0.2 °C (0.36 °F)
Response time                                 < 10 min. in still oil


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