Ladder diagrams

Abstract Programmable Logic Controllers (PLC) have been used in industrial environment to control several different tasks. Such devices can be programmed using one of the languages specified in the IEC 61131–3 standard, such as Ladder or Functional Logic ...

Technology is best interconnecting channel in each part of world with the means of transportation or communication or business which led to a highly increase in the number of cars. Time consumption is essential for cleaning these vehicles or cars etc. Time management is directly proportional to reduction of cost for maintenance. The automatic way is used for man to perform tasks at higher speed. Automatic car washing system is very common in developed countries. It consists of large machines with automated brushes controlled by programmable logic controller (PLC). Automatic car washing system is fully automated with different stages of washing, foaming, brushing, washing, drying. This system has used various components such as PLC MITSUBISHI (FX 2N-25MR), conveyor belt, sensors, dc motors, brushes and dry fans. These components are controlled by programmable logic controller (PLC). In this system, ladder diagram is written for using PLC.

Scenario: A program with a long scan time may not detect short-duration events. A manufacturer of small gasoline engines had an intermittent problem on the final assembly line. Sometimes, a defective engine would not be automatically removed from the line for repair at a " kick-out " station. If an operator noticed a problem with an engine, he/she inserted a bolt into a certain hole in the engine carrier. A proximity sensor before the kick-out station sensed the presence of the bolt, and the PLC activated a hydraulic solenoid to push the carrier (and engine) off the main conveyor and into the repair area. A view of this station is shown in Figure 2.1. Further investigation revealed that the duration of the on pulse of the proximity sensor was approximately 3/4 seconds. One PLC controlled all of the stations on the assembly line and its ladder logic program was quite large. As indicated in the PLC status, the time to scan the ladder logic program was slightly less than 1 second. Hence, it was very likely that a pulse from the proximity sensor could be undetected by the PLC processor. The proximity sensor could be off at the start of the ladder scan, generate an on pulse from a passing bolt in the carrier, and be off at the start of the next ladder scan. Solution: Logic to examine the proximity sensor is placed in a ladder logic routine that is executed every ½ second. If the proximity sensor is detected to be on, an internal coil is turned on for at least 1.5 seconds. The main PLC program is changed to examine this internal coil to determine when to activate the hydraulic solenoid and push a carrier off the main conveyor. 23

Programmable Logic Controllers or PLC, normally a digitized controller is fixed, rigid and industrial digital computer. Earlier days in industry, electromechanical relays, timers, counters and sequencers were widely used. The drawback of using these are many with respect to cost, wiring, and maintenance is more. The advancement in PLC came up to overcome all these factors. The question why PLC is the tool, which gives the control and hold in automation, it provides high gain, improved quality and accuracy, works flexible in criticized and hazardous situation, increase product rate, early time to market, low cost, and mainly since the automation helps in designing and changing over easily from one product to another. In this work, we have designed and simulated the basic gates and compound gates using ladder diagram in PLC, using Indraworks, Indralogic platform. This paper forms a basic for designing complex sequential circuits and helps in developing VLSI circuits. This paper gives a overview of AOI(And OR Inverter) and OAI(Or And Inverter) circuits designed and simulated through PLC with the help of ladder diagram.

Ce rapport est le labeur non seulement d'effort personnel, mais il est surtout le fruit d'une vaste contribution et, ce serait injuste de ma part de l'entamer sans rendre aux personnes, grâce auxquelles ce document a été élaboré, ce dont ils ont droit.

PLC merupakan sistem favorit di dunia industri besar. Salah satu aspek penting dari sistem ini adalah pemrogramannya. Pemrograman yang umumnya digunakan adalah diagram tangga (ladder diagram). Dalam pemrogramannya, PLC membutuhkan sebuah support software. Adapun fitur simulasi dari support software dapat mempermudah pemrograman karena tidak harus membutuhkan hardware PLC. Hal ini juga dapat digunakan untuk pembelajaran pemrograman ladder PLC sebagai upaya untuk meraih kompetensi baik dalam hal pendidikan maupun pekerjaan.
Support software yang banyak dikenal hanya mendukung satu sistem operasi saja. Di sisi lain terdapat sebuah software bernama "Classic Ladder" yang mendukung dua sistem operasi, yaitu windows dan linux. Namun, dokumentasi yang cukup minim menjadi kendala software ini.
Laporan ini membahas tentang pemakaian software ini untuk keperluan pembelajaran pemrograman ladder PLC.

Comprehensive overview of  ( Programmable Logic Controllers ) PLCs and related Industrial Automation Systems.
PLC Basics - hardware modules and IO scans.
Soft-PLC
SCADA-HMI
Drive Control using PLC
Industrial Protocols - Modbus, OPC UA
PLC Sizing and Programming
HMI UI Design
Industrial Automation Hierarchy.  Level0-Level5
PLC programming Languages - ladder(LD), function block (FBD), structured text (STL), Sequential Flow Charts (SFC).
IEC 61131-3 Programming Standard and PLCOpen Interoperability.
Redundancy
Safety Systems
Related Automation Systems - Sub-station Automation, Building Automation.
Comparisons PLC vs DCS, PLC vs RTU, PLC vs PAC, PLC & CNC, PLC & Robot, Robot & CNC.
Machine Vision, Motion Control
Database & ERP Connectivity
IoT vs IIoT, PLC support for the MQTT Protocol, PLC connectivity with Cloud Platforms
PLC Hardware Design.
PLC Software Editors.
Industrial Cyber Security
Dual Use Technology

John Climacus's seventh-century ascetical and spiritual masterwork, the Ladder of Divine Ascent, drew on and reformulated the themes and trajectories of Chalcedonian ascetic spirituality in ways that would prove decisive for later Byzantine theologians. This paper seeks to elaborate the conceptualization of Climacus's spirituality through a sustained exploration of his treatment of angels and his understanding of the ascetic life as 'angelic.' In the monastic literature that Climacus inherited and that formed him, three tensions emerge with respect to the predication of "angelic" to ascetics: optimism and doubt about the possibility of a 'care-free' state, alternative conceptions of "liminal" progress, and opposition of individualism and community. Climacus not only holds together these tensions, but by coupling them with his own original ideas carefully develops the possibility of ascetic imitation of angels.

Ladder diagram (LD) is a common programming language at industry in order to develops control algorithms of discrete event systems. Besides, it is one of the five pro- gramming languages supported by the International Elec- trotechnical Commission through the IEC-61131-3 stan- dard. Petri net (PN) theory is both a graphical and mathe- matical tool, which allows modeling discrete event systems in order to obtain a useful formalization to analyze them in a better way. LD control algorithms are continuously devel- oped based on the experience of control system developers. Therefore, it is still a relevant problem on how to formal- ize a validation for the current and new control algorithms. In the present work, an element-to-element transformation methodology from a LD program to a PN structure is pro- posed. The original part of this manuscript is the proposal of five PN structures where their markings represent the states and dynamic behavior of energized and de-energized coils, which are not included in previous works. Furthermore, this methodology preserves the structural and dynamical behav- ior of the LD in the obtained PN. Two control algorithms of real cases are transformed using the proposed methodology.