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Most of the old machines installed in different industries are managed manually by system operators. This action makes their productivity low and not suitable to cover the needs in other sectors. In addition, these machines are not without risks due to the proximity of the operators to them. The installing a new full system instead of the old one on the same site requires very high costs. So, modernizing the same old system by making its operation automatic has become necessary to reduce the economic cost significantly. In this paper, an automatic control system based on programmable logic controller (PLC) for the cutting steel plate machine that had been managed manually in a factory is designed. The system includes an Encoder that is used to specify the length of the steel plate to be cut by sending a signal to the PLC. The system operation is completed by using human machine interface (HMI) unit to monitor and control the system performance by the system operator. A practical test for the developed system offered more productivity (more than 30%), more safety, reduces human efforts and the total daily production cost (less than one third). [ABSTRACT FROM AUTHOR]

In this paper one industrial process and the automation of that industrial process are considered. In automation, the most important part is the controller. The controller is actually the brain of the process, and it regulates the switching on and off of all the elements involved in the process itself. The controllers that are used in industrial automation are called programmable logic controllers (PLC controllers). With an example it is shown how the PLC controller can be programmed with a Ladder Diagram. PLC programming involves creating a set of instructions that govern the behavior of a PLC to control machinery and processes. These instructions are written using specialized software tools and are executed in a sequential manner. The primary objectives of PLC programming are to ensure the safe and efficient operation of automated systems, maintain process accuracy, and facilitate quick responses to changing conditions. [ABSTRACT FROM AUTHOR]

The Ladder Diagram (LD) is an industry-standard programming language for constructing automated manufacturing systems (AMSs) control algorithms. Petri net (PN) theory, on the other hand, is a mathematical and graphical modeling tool for AMSs. Multiple types of PN-based LDs are designed for AMSs with highly complicated LD structures. Thus, it is necessary to propose a technique that can assist in the minimization of the structural complexity of LDs. The main purpose of this study is to propose a methodology for the implementation of LDs in AMSs. First, a colored resource-oriented Petri net (CROPN) is developed for modeling and guaranteeing the deadlock-free behavior of AMS. Second, a ladder diagram CROPN (LDCROPN) is constructed in order to transform the CROPN into an LD. The proposed LDCROPN is assessed using instances from the literature. The results show that the LDCROPN is effective, has a simpler structure, and has less computational overhead than existing techniques.

Powerful advantages of programmable logic controller (PLC) dominate process industries. Scan time of PLC increases with the number of inputs, rungs added in ladder diagram (LD). Researchers have identified and proved that field programmable gate array (FPGA) is more suitable than PLC for high speed applications. PLC executes the instructions represented through LD. PLC programmers are not familiar with FPGA programming. But, FPGA does not support LD based programming. This work has developed application software to generate equivalent VerilogHDL code for LD using LabVIEW. Novelty in this work is that each rung is defined using an "assign" statement which helps simultaneous execution of all the rungs. A data acquisition system was created to monitor the digital signals handled by the FPGA. The software was verified with a case study of substances mixing and traffic light control system. [ABSTRACT FROM AUTHOR]

In a modern economy, any automation or control aims to increase the competitiveness of a product, either directly, through cost and quality, or indirectly, through improving working conditions. Control implies the management of some dynamic systems having continuous states. These systems are described by differential equations and generally have analog inputs and outputs. The mining industry cannot be an exception to this and in this paper the authors came up with an idea of a simple automation of a coal transport system using a mini-PLC. This idea consists in the development, with the help of the Ladder Diagram programming language (LD), of a simple program for the command, control and signaling of a transport system composed of three belt conveyors. [ABSTRACT FROM AUTHOR]

Bottled-beverage production systems require considerable machinery and sophisticated control systems. A malfunction in the production system can result in machine stoppages, thereby decreasing productivity and resulting in the production output not meeting the required target. Therefore, the problem of frequent stoppages of the production system must be resolved. The 'Fast Restart Function' is a proposed feature that can help reduce machine downtime by decreasing the time required for the product to drain from the conveyor. In this study, using this strategy, the investigated manufacturing system's efficiency increased from 86.81% to 90.29%, enabling an increase in the average production capacity by 27,187 bottles per day, i.e., a 3.48 percent increment of the daily capacity. When employed in inefficient production systems or systems facing frequent shutdowns, this system is of considerable value for mitigating production stoppages. [ABSTRACT FROM AUTHOR]

The 12-lead electrocardiogram (ECG) of a 79-year-old male patient with recurrent pre-syncope showed irregular sinus rhythm with constant PR interval and left bundle branch block (LBBB) with intermittently blocked P waves. The beat following the blocked P wave had a narrower QRS with a shorter PR interval. The phenomenon of bilateral bundle branch block explains the sudden improvement in the atrioventricular conduction.

A typical example of discrete event systems (DESs) is a reconfigurable manufacturing system (RMS) whose can be changed and become more complicated during its operation. Thus, an effective tool needs to be developed to create both high- and low-level DES implementation. The ladder diagram (LD) is a common programming method for controlling DESs. Petri nets (PNs) represent the most important graphical and mathematical tool that can be used to provide an integrated solution for the design, modeling, analysis, control, and implementation of DESs. Various types of PN-based LDs are developed for DESs, which have high structural complexity of the LDs. Therefore, an approach that can facilitate the elimination of the LDs' structural complexity needs to be developed. The main objective of this paper is to develop a two-step approach for LDs implementation for RMSs with dynamic changes. First, a colored resource-oriented Petri net (CROPN)-based algorithm is proposed for a rapid and valid configurations of an RMS. Second, a ladder diagram colored resource-oriented Petri net (LDCROPN) is developed to convert the CROPN into an LD. The developed approach is evaluated using examples in the literature. Moreover, the results demonstrate the effectiveness of the developed approach for LD implementation under RMS specification changes.

Featured Application: The presented implementation is aimed to deliver high performance logic controllers with very short and predictable response time. The controller is automatically synthesized from the delivered program given according to IEC61131-3 requirements. The user can concentrate on developing control algorithm while synthesis process to FPGA device is fully automatic. Programmable logic controllers are commonly used in automation systems. Continuously growing demands result in the growth of control program complexity. The classic approach, based on programmatic serial-cyclic execution, results in an unacceptable extension of response time. To overcome long response time massive parallel program execution is proposed. It utilize direct in hardware program implementation in field programmable devices. The paper brings a formal method of representing control programs using flow graphs and enabling single cycle computations. The developed method accepts ladder diagrams (LD) and sequential function charts (SFC), according to IEC61131-3 standard requirements. It is capable of handling logic and arithmetic computations, enabling its hardware mapping. The intermediate form is optimized using flow graph representation and BDDs for analyzing logic dependencies. The BDD representation of logic dependencies enables direct mapping to lookup tables of a selected FPGA family. All the above steps deliver high-performance and direct hardware implementation of the control program given by standard languages. The controller response time is short, predictable, and independent from logic conditions during program execution. [ABSTRACT FROM AUTHOR]

We present a case of a 60-year-old female patient, where the initial ECG showed a bradycardic rhythm due to early non-conducted P waves. The 24h-Holter analysis showed frequent junctional beats, dissociated from the P wave or with retrograde conduction, often related to early blocked P waves (in bigeminy or trigeminy) and periods of an apparent second-degree Mobitz II atrioventricular block (AVB). We believe that these Holter findings represent the main forms of presentation of junctional extrasystoles with varying types of conduction, including anterograde conduction and retrograde block, anterograde and retrograde conduction, anterograde block and retrograde conduction and anterograde and retrograde block, simulating Mobitz II second-degree AVB. The observation of these multiple forms of junctional extrasystole presentation in a 24h-Holter can help to better understand the behavior of junctional or Hisian premature beats and in the differential diagnosis with true second-degree AVB and blocked premature atrial contractions. [ABSTRACT FROM AUTHOR]

Programmable logic controller (PLC) is one of the most important components in today’s manufacturing. Its performance-based microprocessor and software have been a bottleneck for improving its efficiency. To enhance the PLC performance and flexibility, a new PLC design based on field programmable gate array (FPGA) has been a hot topic because of its parallel execution mechanism and reconfigurable hardware structure. From practical viewpoint, in this paper, the authors propose an approach to implement the existing ladder diagram (LD) inside FPGA making full use of the advantage of FPGA device. The essential of this research includes two issues: (a) analyze the LD program and organize it with sequential and parallel structure and (b) implement the sequential and parallel structure of the LD program with hardware description language inside FPGA. To the first work, the condensed simultaneity graph theory is applied to optimize the LD program with sequential and parallel structure. To the second work, Boolean equations are taken as the bridge to convert the optimized LD program to the hardware description language program. Finite state machine is used to generate sensitive signals to guarantee that the performance of the converted very high-speed integrated circuit hardware description language design is the same as the original ladder diagram. A case study is practiced to verify the proposed approach in this paper.

Programmable logic controllers are commonly used in automation systems. Continuously growing demands result in the growth of control program complexity. The classic approach, based on programmatic serial-cyclic execution, results in an unacceptable extension of response time. To overcome long response time massive parallel program execution is proposed. It utilize direct in hardware program implementation in field programmable devices. The paper brings a formal method of representing control programs using flow graphs and enabling single cycle computations. The developed method accepts ladder diagrams (LD) and sequential function charts (SFC), according to IEC61131-3 standard requirements. It is capable of handling logic and arithmetic computations, enabling its hardware mapping. The intermediate form is optimized using flow graph representation and BDDs for analyzing logic dependencies. The BDD representation of logic dependencies enables direct mapping to lookup tables of a selected FPGA family. All the above steps deliver high-performance and direct hardware implementation of the control program given by standard languages. The controller response time is short, predictable, and independent from logic conditions during program execution.

Illuminance in a room comes not only from lighting lamps, but also from natural daylighting. However, if it is excessive, it may cause a glare. Thus, it is necessary to optimize the day lighting automatically. This paper presents the design and testing results of vertical curtain automation utilizing PLC TM221 and ladder diagram software. The program performed an analogue logic operation. The 4-20 mA current analogue signal of light sensor transmitter output was converted to 2-10 V using 50 Ω resistor, in the provision of the PLC analogue input, in recording of 0- 2000 lux. In the design of ladder diagram, the sensor, as the PLC input, was the reference value for the programming of SoMachine software. It was necessary to adjust the upper and the lower limits of the curtain on the limit switch, connected to the curtain motor. Hereafter, it was conducted the tests of lux values. The initial step, in the automatic open and close curtain program making, was to determine the visual comfort specified reference value of 230 lux in the classroom. As the reading sensor under or same as 350 lux, the curtain would go up. Otherwise, it would go down. As the curtain rose, it would continue to rise up to 230 lux, it would remain motionless, and it would be locked on the sensor reading between 220 lux and 238 lux. Otherwise, it would continue to go up to 230 lux, to the upper limit set by the limit switch. As the sensor reading of 239 lux and above, it would turn off as the sensor reading under or same as 350 lux. Otherwise, the curtain would go down, and it would read whether the sensor reading under or same as 201 lux. As the curtain went down, it would continue up to 230 lux, it would be quiescent, and it would be locked on the sensor reading between 220 and 238 lux. Otherwise, the curtain would go down continuously to get 230 lux, up to the lower limit set. As the sensor read same as or under 201 lux, it would turn off the 350 lux (or less) sensor reading and the curtain would go down to the lower limit. The obtained results of the design, the curtain could open and close automatically. The automatic motion of the curtain was based on the illuminance in the room. The opening of the curtain was to keep the illuminance of 230 lux in the room and it would be held to the value between 220 lux and 238 lux. The locked curtain was done so that it was not too sensitive to any change in the sensor signal. [ABSTRACT FROM AUTHOR]

Preexcitation alternans and orthodromic atrioventricular reciprocating tachycardia were diagnosed in a 3-month-old Boxer. The images described here show how conventional electrocardiographic techniques (12-lead surface electrocardiography, 24-hour Holter monitoring, and ladder diagram) can be interpreted to gain detailed information on presence of canine atrioventricular accessory pathways and their conduction properties. [ABSTRACT FROM AUTHOR]

There exist numerous modelling techniques and representation methods for digital control algorithms, aimed to achieve required system or process parameters, e.g. precision of process modelling, control quality, fulfilling the time constrains, optimisation of consumption of system resources, or achieving a trade-off between number of parameters. This work illustrates usage of Finite State Machines (FSM) modelling technique to solve a control problem with parameterized external variables. The structure of this work comprises six elements. The FSM is presented in brief and discrete control algorithm modelling is discussed. The modelled object and control problem is described and variables are identified. The FSM model is presented and control algorithm is described. The parameterization problem is identified and addressed, and the implementation in PLC programming LAD language is presented. Finally, the conclusion is given and future work areas are identified.

This paper deals with a possibility of a modeling of a block system. A created modeling tool contains a graphic editor of a track section configuration and a graphic editor of control algorithms, which serves on a writing of behavior algorithms of exterior devices of the block system. In order to the modeling of the block system was possible general models of basic exterior devices and a programming language for the writing of control algorithms to a source code form had to be created. It describes a work with different parts of the modeling tool and their possibilities on a selected example of an automatic block. The paper also describes an ability of to simulate a modeled block system activity and an ability to simulate the movement of the train in track section

Those robots that feed LCDs in LCD manufacturing processes are called carrying robots. In general, programmable logic controllers (PLCs) are used as control components in semiconductor manufacturing equipment. PLCs not only have higher processing speeds compared to other control systems and complex functions and can easily cope with various forms of functional changes but also are very conveniently maintained. Ladder diagrams (LDs) are the most frequently used as control programs to drive PLCs. However, a sequential function chart (SFC) is used to complement shortcomings of LD programs. Advantages of these SFC programs are easily understandable control flows and easy maintenance. In the present study, a method of controlling carrying robots in LCD manufacturing processes using SFC language was developed and the validity of the method was checked. [ABSTRACT FROM AUTHOR]