Resonant sensing system and method for monitoring properties of an industrial fluid

A sensing system comprising:

• a sensor including a sensing region configured to be in contact with an oil, the sensing region including electrodes and a sensing region circuit electrically connected to the electrodes, the sensing region circuit including an inductor-capacitor-resistor (LCR) resonant circuit, the sensing region circuit configured to generate an electrical stimulus having multiple different frequencies that is applied to the oil via the electrodes;
• and
• one or more processors configured to receive one or more electrical signals from the sensor representative of an impedance response of the sensing region to the electrical stimulus, the one or more processors configured to analyze the impedance response to extract resonance parameters of the impedance response and to determine, based on the resonance parameters that are extracted, a contaminant concentration of an external contaminant in the oil, a base concentration of basic components in the oil, and an acid concentration of acidic components in the oil.