placed to control the reverse flow.

placed to control the reverse flow. A control signal (4–20 mA) from the controller is given to the pneumatic control valve through an I/P (current to pressure) converter. A rotameter is placed at the outlet of a control valve to display the flow rate (Q’). By varying the control signal, the pressure from the compressor to the I/P converter can be varied and the valve position can be changed which results in a change in flow rate (Q’) at the output of the valve. Furthermore, the flow is directed back to the reservoir, and an orifice flow meter exists to monitor the flow rate via a differential pressure transmitter. Figure 2 shows a picture of the actual process. Figure 1. Flow process workflow. Before going into the working of the proposed system a brief introduction to control valves and its faults are discussed here. 2.1. Control Valve The control valve used in our application is a pneumatic valve which means the actuator used for opening and closing the valve is pneumatic in nature. A cross-section of such a valve is shown in Figure 3 [2]. The purpose of a valve is to hinder the flow of the liquid through a pipe. A valve plug Electronics 2019, 8, 1062 3 of 15 considered in the frequency domain as the variation in the data was most noticeable in this method as compared to fast Fourier transform (FFT) data. These PSD values are computed for both normal and faulty systems, which in turn are combined to form the training data set. A support vector machine is used to classify between the normal and faulty data from the training set. Since this method involves a non-contact type of measurement and the detection is done using a machine learning algorithm, this gives us a method to update the detection process to include more faults or to enhance the performance later on. To the best of our knowledge this type of sensing in combination with artifificial intelligence has not been carried out on a real-time system regarding control valves. After the introduction in the fifirst section, the experimental setup used to perform the desired work is discussed, followed by a problem statement, problem solution, results and discussion and fifinally a conclusion. 2. Experimental Setup