Abstract: In the examples provided herein, a system includes an electrochemical sensor having two electrodes inserted in a fluid to be tested, where an alternative current (AC) voltage is applied across the two electrodes; an electrochemical sensor having two electrodes inserted in a fluid to be tested, wherein an alternative current (AC) voltage across the two electrodes; and a frequency response analyzer to analyze the measured the electrical response across multiple frequencies. The system also includes a memory to store a baseline of the electrical response across multiple frequencies, and a processor to determine from the stored baseline and the measured electrical response whether the electrical response is outside a predetermined range.

Abstract: In the examples provided herein, a system includes an electrochemical sensor having two electrodes inserted in a fluid to be tested, where an alternative current (AC) voltage is applied across the two electrodes; an electrochemical sensor having two electrodes inserted in a fluid to be tested, wherein an alternative current (AC) voltage across the two electrodes; and a frequency response analyzer to analyze the measured the electrical response across multiple frequencies. The system also includes a memory to store a baseline of the electrical response across multiple frequencies, and a processor to determine from the stored baseline and the measured electrical response whether the electrical response is outside a predetermined range.

Abstract: A control apparatus is provided. The control apparatus includes an electronic engine, a facility engine, and a control engine. The electronic engine to communicate with an electronic control system. The facility engine to communicate with a facility control system. The control engine to provide an interface between the electronic engine and the facility engine to unify control of the electronic control system and the facility control system.