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Distributed Control System (DCS)
Published in Chanchal Dey, Sunit Kumar Sen, Industrial Automation Technologies, 2020
Designing of batch control scheme is more tedious than designing of continuous control scheme as every detailed information related to the procedure and related data are required to be provided. Recipe for a particular batch process is created and managed by the recipe management function. The created recipe is called a ‘master recipe’. When the master recipe is used in an actual process, the master recipe is converted into a form usable in an actual process called ‘control recipe’. It is downloaded in the FCS and is ready for use. Recipes can be organized into recipe groups. A recipe consists of recipe header, procedure described by SFC, recipe formula, and equipment requirement. Batch process status can be observed in the special batch management monitoring window. After a recipe is executed, resultant data are acquired and can be output as batch reports. The batch control flow diagram is shown in Figure 3.48.
Implementation of Digital Control Using Digital Signal Processors
Published in Ali Emadi, Alireza Khaligh, Zhong Nie, Young Joo Lee, and Digital Control, 2017
Ali Emadi, Alireza Khaligh, Zhong Nie, Young Joo Lee
Figure 16.8 presents the control flow of a classical PI control with anti-windup and the analog implementation of PWM modulation based on Figure 16.4. In the PWM modulator, dboost must be less than one to prevent the inductor current iL from being extremely high in boost operation mode. In other words, vctrl is always lower than 2vmod as seen in Figure 16.8. The conversion of the control flow into the discrete control follows the control flow diagram. The sampling periods of each control loop, system stability, and control gains can be selected using various discrete control techniques [20].
Computer-Aided Control Systems Design
Published in William S. Levine, Control System Fundamentals, 2019
C. Magnus Rimvall, Christopher P. Jobling
Figure 23.12 shows a typical control flow diagram or flowchart. The connections in this case represent the order of execution. The triangular blocks are decision blocks while the square blocks are variable assignment blocks written in a PASCAL-like language. Also shown are a multiway branch and a truth table. BEACON requires that the control flow diagrams produce structured code which equivalently means that a diagram can be implemented as sequence of if-then-else statements without go-to’s.
The influence mechanism and control strategy of relative humidity on hot air drying of fruits and vegetables: a review
Published in Drying Technology, 2021
Wei-Peng Zhang, Xu-Hai Yang, A.S. Mujumdar, Hao-Yu Ju, Hong-Wei Xiao
After initial drying stage, the material temperature has already reached to a high level. Drying process is transited into constant drying stage. It is supposed that RH need to be decreased to improve the mass transfer process. Meanwhile, the material temperature is detected at regular intervals e.g., 3 min, during moisture evaporation process. If the latter temperature is more than the former temperature a fixed value, e.g., 1 °C, it is illustrated that the material temperature appears to a rising tendency, the energy absorbed is maily used to increases material temperature and less is used to evaporate moisture. In other words, the material temperature is not large enough to support an internal moisture diffusion driving force. This phenomenon is mainly because the bondage of the material dry matter to water is becoming more strongly, so that higher material temperature is required to drive internal moisture diffusion to surface. In this case, it is suggested that the material temperature should be increased. As a result, when the material temperature shows an increasing tendency, it is time to stop dehumidifying humidity to increase RH value. After increasing RH, if the adjoining interval material temperature difference is more than a fixed value, e.g., 3 °C, it means that material possesses a bigger temperature value to further internal moisture diffusion. And then it is time to dehumidify humidity to decrease RH to accelerate surface evaporation. As repeating this cycle, material achieved a high drying rate with high sample temperature. Both heat and mass transfer process are intensified. The control flow diagram is shown in Figure 12.
A creation method of comprehensive cases and specifications for hardware and software combined test to detect undesirable events of an industrial product using HAZOP
Published in SICE Journal of Control, Measurement, and System Integration, 2022
Masakazu Takahashi, Kouji Ueno, Yunarso Anang, Yoshimichi Watanabe
Next, the method of extracting parameters from the specifications is explained. The design information of industrial products consists of the hardware design specifications and software design specifications. The parameters are extracted from the software specifications, and the control signals are extracted from the hardware specifications and software specifications. Software specifications are often written using the Data Flow Diagram (DFD) and Control Flow Diagram (CFD) of the structured analysis method [21] or Unified Modelling Language (UML) [22] of the object-oriented method. The parameter extraction method from each method is explained as follows.
Experimental validation of solar PV sustained ZSI based Unified Active Power Filter for enrichment of power quality
Published in Automatika, 2021
The power backup state is activated through the usage of a battery storage device at night or when solar irradiation is inaccessible. The battery-powered ZSI-UAPF compensates for the harmonics and reactive power burden. The mode is facilitated based on the PV power output and the battery SOC. The battery backup mode is achieved through ZSI to maintain the continuity of the compensation effectively. Figure 3 shows the control flow diagram for the power backup state. Uninterrupted supply