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Prototyping of automated systems
Published in Fuewen Frank Liou, Rapid Prototyping and Engineering Applications, 2019
The primary function of a PLC is to control automated processes in a system. A PLC is designed to track a large number of inputs and issue a large number of commands in a very short amount of time (milliseconds). A PLC uses a symbolic programming language that makes it simple for the programmer to modify the way that the outputs are sent based on the input signals. In other words, it can be programmed with a form of programming known as ladder logic. Ladder logic is a program that is basically structured like a flowchart. The program uses four different types of registers in order to function. For example, the X registers are used as inputs, the Y registers are used as outputs, the D registers are data that can form integers, hex, and real numbers, and the R registers are the internal relays. X’s and Y’s are pointers to the actual terminal strip connectors on the PLC.
Programmable Logic Control Systems
Published in L. Ashok Kumar, M. Senthilkumar, Automation in Textile Machinery, 2018
L. Ashok Kumar, M. Senthilkumar
Timing diagrams can be valuable when designing ladder logic for processes that are only dependent on time. The timing diagram is drawn with clear start and stop times. Ladder logic is constructed with timers that are used to turn outputs on and off at appropriate times. The basic method is: Understand the process.Identify the outputs that are time dependent.Draw a timing diagram for the outputs.Assign a timer for each time when an output turns on or off.Write the ladder logic to examine the timer values and turn outputs on or off.
Boolean Logic
Published in Douglas O. J. deSá, Instrumentation Fundamentals for Process Control, 2019
Relay logic, the last topic we shall cover in this chapter, is an important one in that the configuration of many of the programmable controllers in use is based on this technique. When such a method is used, it is referred to as ladder logic, the reason being that the configuration is graphical, in essence with one line on the diagram representing (in most cases) a logical operation; hence a series of operations give the appearance of the rungs of a ladder. In recent times, however, ladder logic has been enhanced through combination with sequence logic using a technique called Grafcet that has its origins in France as a method to configure complete programmable logic controllers (see Chapter 25).
1-D convolution neural network based leak detection, location and size estimation in smart water grid
Published in Urban Water Journal, 2023
Pooja Choudhary, B. A. Botre, S. A. Akbar
During RW mode, the raw water tank discharge valve opens, and raw water is pumped to layer 1 and layer 2 of the water distribution network. The treated water tank discharge valve will open in TW mode, and treated water is pumped to the distribution lines. RO mode is used for water purification purposes. RO works by using a high-pressure pump to increase the pressure on the salt side of the RO and force the water across the semi-permeable RO membrane, leaving almost all of the dissolved salts behind in the reject stream. The filtered water then passes through the UV protection to kill the bacteria. In descaling mode, the descaling tank feeds the descaling agents and the water inlet from the treated water tank manually operated valve through pump during the descaling process to remove the oxides in the line. Descaling is used for cleaning the network for the long-term efficiency of the model. The ladder logic programming is based on the running states of the whole water grid system. The macros containing ladder diagrams are uploaded and stored in dynamic read and write memory of the main processor module of PLC. The tags were created in the control tag list and were mapped to virtual plant signals with the corresponding tag name of process variable ethernet communication protocol. Different solenoid valves (Sol, Sov), Post Indicator Valves (PIV), hand valves, pump and motor conditions are turned ON and OFF as per the required mode.
An approach to develop a digital twin for industry 4.0 systems: manufacturing automation case studies
Published in International Journal of Computer Integrated Manufacturing, 2021
David Guerra-Zubiaga, Vladimir Kuts, Kashif Mahmood, Alex Bondar, Navid Nasajpour-Esfahani, Tauno Otto
TIA Portal by Siemens is the software used throughout this study to write and execute the program for each PLC and to view the execution of that logic in real-time. The program is written in ladder logic with a tag list created from the stored memory, input, and output addresses, which are mapped to the Process Simulate model. The HMI is configured here as well, where each button is mapped, and indicators are linked to the appropriate memory bits of the PLC. Another option that is set in TIA Portal is the ability to compile the program for virtual PLC use, a crucial setting for linking the program to PLCSIM Advanced. Figure 4 illustrates the implementation of ladder logic code for the manufacturing system using the TIA Portal. All physical connections are configured here, and TIA Portal recognizes the virtual PLC as indistinguishable from a physical module. This allows for the same kind of connection as connecting an additional PLC or an I/O device like a VFD. Once the connections are configured, the hardware configuration must be flashed on each device separately accompanied by any programming required.
Energy efficiency in pneumatic conveying: performance analysis of an alternative blow tank
Published in Particulate Science and Technology, 2021
Adriano Gomes de Freitas, Vitor Furlan de Oliveira, Yuri Oliveira Lima, Ricardo Borges dos Santos, Luis Alberto Martinez Riascos
Regarding the monitoring of the parameters of this system, two pressure transmitters (one just before and the other just after the air inlet valve) and a volumetric flowmeter are used. The system is controlled by a Programmable Logic Controller (PLC), which is also associated with a Human Machine Interface (HMI) and a Supervisory Control and Data Acquisition (SCADA) program and support automation with Ladder logic, consisting of the user interface, performing logical, sequential and timing tasks to control and measure the automation applications of the conveyor system. A simplified schematic representation of the system is presented in Figure 2(a) and its correspondent control system representation is shown in Figure 2(b).