The accelerometer is placed near th

The accelerometer is placed near the output of the control valve, as shown in Figure 5, which gives us the vibration data of the control valve for changes in the flow. Sensor placement is considered based on the point of maximum vibration, as the sensor is coupled to the flange of the valve. The acquisition setup consists of a PCB 352C03 ceramic shear ICP® accelerometer, which is a single axis vibration sensor with a sensitivity of 10 mV/g and frequency range of 0.5 to 10000 Hz [29]. The NI 9234 Sound and Vibration module, which is designed for the measurement of IEPE (Integrated Electronics Piezo-Electric) sensors, is used for the acquisition and conditioning of the accelerometer data. This module needs either a CompactDAQ or CompactRIO or a Carrier module. Since processing power is not required for the proposed method, a carrier was enough to acquire data. Electronics 2019, 8, 1062 6 of 15 position as expected. The resulting fault is termed the insuffiffifficient supply pressure error. The resulting changes in the flflow rates due to these induced errors at the output of the control valve are detected by the accelerometer as a change in vibration and are used by the detection algorithm. Both the inflflow fault and insuffiffifficient fault cause variation in the outlet flflow even with a proper control signal, and this change in outflflow will affffect the process stability. Hence to avoid this situation it becomes necessary to detect the error so that the controller can be notifified of the cause of error at the output and a suitable method can be designed to incorporate the additional information into the controller. A method is proposed to identify both faults automatically. 3. Methodology To detect the faults mentioned above, a system is proposed that uses non-invasive techniques using vibration analysis. An accelerometer is placed at the outlet to obtain the vibration data needed for the detection. Since it is possible to estimate the flflow rate using a vibration sensor as mentioned in [28], it will also be possible to detect a fault in the flflow rate. The placement of the accelerometer is considered fifirst by taking into account that any changes in the control valve operation are directly reflflected at the output of the valve. Second, it is seen that the flflow becomes uniform after a distance of over “6 times pipe diameter from the valve” which would mean that the lower the effffect of vibration the farther the accelerometer is placed. In the proposed work, a distance of two times the diameter of the pipe from the coupling of pipe and valve is maintained. Third, any controller in the process would use the output flflow rate as the parameter to be monitored and any changes in this would affffect the controller operation, hence it is intuitive to measure the same. The accelerometer is placed near the output of the control valve, as shown in Figure 5, which gives us the vibration data of the control valve for changes in the flflow. Sensor placement is considered based on the point of maximum vibration, as the sensor is coupled to the flflange of the valve. The acquisition setup consists of a PCB 352C03 ceramic shear ICP® accelerometer, which is a single axis vibration sensor with a sensitivity of 10 mV/g and frequency range of 0.5 to 10000 Hz [29]. Figure 5. Placement of accelerometer to capture vibration signal. The NI 9234 Sound and Vibration module, which is designed for the measurement of IEPE (Integrated Electronics Piezo-Electric) sensors, is used for the acquisition and conditioning of the accelerometer data. This module needs either a CompactDAQ or CompactRIO or a Carrier module.