Develop a variety of specific techniques for diagnosing malfunctions in circuits containing. Troubleshooting industrial controls training system. Troubleshooting plc circuits training software troubleshooting plc circuits uses a plc simulator to teach troubleshooting electrical circuits and the plc. Locating faulty components, identifying power quality problems, and troubleshooting circuits are just a few of the issues the maintenance technician may be confronted with when repairing. For instance, in this simple circuit, a logic probe will give correct high and low readings at test point 1 tp1, but it will always read low even when the led is on at test point 2 tp2. Chapter 10 sensors, safety, analog and troubleshooting. At 334 pages, its the perfect companion to programmable controllers. Theory and implementation programmable controllers an industrial text company publication atlanta georgia usa second edition l. The technology inherent in the programmable logic controller plc eliminates the requirement for electromechanical devices such as control relays and timers and allows for exact operation of the preprogrammed formulas through electronic circuits, timers and counters. Maintenance troubleshooting industrial controls training system. Troubleshooting plcs can be started by checking the healthiness status of cpu, io modules, fuse blowout and different plc failure reasons including wiring, field transmitters healthiness status or transmitter configuration. Plc latching and unlatching circuit this is plc program for latching and unlatched circuit for output. Electrical motor control circuits is a product developed by business industrial network. Troubleshooting plc circuits training software troubleshooting plc circuits uses a plc simulator to teach troubleshooting electrical circuits and the plc control.
There are lots of industries and services to which processes can be employed to automate the work flow using plc circuits. The plc will update only at the end of the program logic. A programmable logic controller plc is a specialized computer used. Hardware troubleshooting verify per installation manuals. It uses a programmable memory to store instructions and specific functions that include onoff control, timing. In this module, your professionals will diagnose and repair over 60 faults in each of three simulated circuits containing plc. Cxprogrammer, the programming software for all omrons plc series, is fully integrated into the cxone software suite.
Conduct a hazard assessment and follow approved safe work practices. Electrical troubleshooting 1 before using a voltmeter on electrical components, do the following. There have been quite a few projects about using a pic to simulate or replace a plc. Photo by rob ellis when handling auto repairs, you may feel overwhelmed and lost. Instructor will create issues and students need to diagnose and resolve the problem. Problem description in some conveying system operator.
Control circuits are generally designed so that an individual circuit controls only one function of a particular process or machine. Troubleshooting plc circuits by testing thumbwheel switches, december 1995, p. Troubleshooting an open circuit faults in the control. The tstrainer is designed to assist industrial electrical contractors, industrial maintenance, technicians, apprentices and other students with systematic. The removable connectors on the dl105 make this relatively easy. At the end is just an example how our software uses realworld workorder system to track student while doing electrical troubleshooting with our. To minimize the risk of potential safety problems, you should follow all applicable local, state and national codes that regulate the installation and.
If the customer does not have one to relate, one must be found by testing the units performance. If the field device connected to an input module doesnt seem to turn on, a problem may exist somewhere between the line connection and the terminal connection to the module. Troubleshooting an open circuit faults in the control circuit. Introduction to programmable logic controllers plc s industrial control systems fall 2006. They are called ladder diagrams because they resemble a ladder, with two vertical rails supply power and as many rungs horizontal lines as there are control circuits to represent.
Two examples are explained on racing conditions in the plc. The programmable logic controller plc was invented in the 1960s to replace the sequential relay circuits traditionally used in machine control. Lecture introduction to plc s mme 486 fall 2006 9 of 47. Perfect your plc circuit troubleshooting process by troubleshooting more than 60 faults in a safe training environment. This site is not directly affiliated with business industrial network. Mar 07, 2015 this is usually a case of not understanding how the plc scans logic. Plc troubleshooting and diagnostics machine tool help. New parametersetting dialogues reduce setup time, and with standard function blocks in iec 61. Basic troubleshooting strategies basic electricity pdf version. Advantages of a plc control system easier to troubleshoot. Basic circuit troubleshooting worksheet basic electricity. Basic circuit troubleshooting worksheet all about circuits.
Ladder diagram example a manual mixing operation is to be automated using sequential process control methods. Problems with transmitters usually occur because of wiring. Isolating portions of the circuit is a good way to identify the area of concern. Ch 10 sensors, safety, analog and troubleshooting 1 chapter 10 sensors, safety, analog and troubleshooting we now look outside the control panel at devices and methods of design that affect the design of the plc and the overall project. Learn and determine the operation of plc circuits using ladder diagrams, wiring diagrams, inputoutput schematics, and data sheets. For loose cables such as ones in a cable tray maintain a minimum of 6 inches between input power, output power and the controls, unless they have their own grounding shield such a metal conduit. We will add more posts soon on many topics such as how to build a solar generator, and this post will help build the basics on which those posts will expand. Parallel rlc circuit and rlc parallel circuit analysis. It uses logic functions, which are programmed into its memory, via programming software. If the current is less than 22ma and the supply output voltage is low, then the power supply could be faulty. Troubleshooting input modules an input circuit responds to an input signal in the following manner. Circuits hands on write plc program and troubleshoot. The program takes the place of much of the external wiring that would be required for control of a process.
Troubleshooting plc circuits troubleshooting plc circuits tplc is the fourth in our series of simulationbased training modules. Electrical motor control circuits free download for. A plc is a solidstate, electronic device that controls the operation of a machine. Hardware troubleshooting tips for troubleshooting control system if installation and startup procedures were followed closely, controller will give reliable service.
The included 32 page electrical troubleshooting pdf lab manual also provides more introduction to troubleshooting control circuits. This workbook provides not only valuable summaries of each of the text. The symptom should automatically lead to the method of troubleshooting. At the completion of the course the students take the pmmi plc level 1 certificate. Examine the following illustration of a simple batteryswitchlamp circuit, connected together using screwterminal blocks, each connection point on each terminal block identified by a unique number. Open circuit faults an open circuit fault is any fault that stops the operation of a machine due to an open wire or component. They can provide valuable information about the wiring, and inputoutput io modules within the unit. Block diagram of programmable logic controller plc. We have discussed the ladder logic instructions before and looked at the simple ladder logic programs in chapter 2. This programmable logic controller training simulates real world faults allowing user to use simulated vom, ladder logic and other tools to troubleshooting control circuits wired to the plc controller simulator. Electrical troubleshooting of a relay control circuit. Lets develop our procedure for troubleshooting an open circuit in the control circuit. At some point you will find one or more relays that have to be activated for it all to work and if they get their power directly from the plc outputs then you have to look at all the plc inputs that have say in things.
Troubleshooting a 420ma loop page 3 of 4 power supply, malfunctioning electronics, etc arent part of troubleshooting a 420ma loop, unless the loop is being powered by a supply that is part of the indicator and one can continue by repairing the indicator to resolve these issues. Siemens simatic s7 manuals and guides southern plcs. Actual outputs and inputs are not read until the end of the scan of the plc. The lab manual can be accessed via the software and you can also optionally print it. A plc is a complete system, probably using many chips, so its larger, more expensive, and not as versatile as you are limited to what the designer included.
The skills of the competent technician must include a methodical means of troubleshooting and root cause analysis. Problem description in some conveying system operator fills tank manually by operation water pump manually. Basic logic gate troubleshooting worksheet digital circuits. If there has been a major power surge, it is possible the plc internal power supply has been damaged. Use insulated gloves, tools, blankets, and barriers if required. Look for improper voltages, improper waveforms, obvious component overheating. The opposition to current flow in this type of ac circuit is made up of three components. The first step in plc troubleshooting is to decide if the problem is internal to the processor or in the io system. At the completion of the course the students take the pmmi plc level 1 certificate test. Practical troubleshooting of electrical equipment and control circuits by mark brown, jawahar rawtani, dinesh patil there is a large gap between what you learn in college and the practical knowhow demanded in the working environment, running and maintaining electrical equipment and control circuits. This plc simulator used for plc training creates faults for user to learn skill of troubleshooting plc controls. In general, the plc will scan from left to right, top to bottom. The best knowledge is obtained through practice and actual troubleshooting conditions.
These manuals are specifically made up for the individual panel, and are generally sufficient for any or all problems which may be encountered. Any supplement and comments are welcome how to troubleshoot a plc system. This will permit you to manually activate the field device. Understanding basic electricity can be invaluable in both safety, as well as when troubleshooting and repairing an electrical circuit. Electrical motor control circuits free download for windows. Practical troubleshooting of electrical equipment and control. The plc troubleshooting training with plc maintenance. The output circuits cannot detect shorted or open output points. We know from above that the voltage has the same amplitude and phase in all the components of a parallel rlc circuit. Practice again and again is the solution in my opinion. This is a basic course, without any prerequisites, that. The following is a short discussion concerning basic electrical troubleshooting.
Automation systems troubleshooting has in general the same tactic in order to find the solution of systems fault. The problem could be in the chandeliers wiring open wire connection, open connection in socket, or in the bulb itself burnedout filament. Ladder logic ladder diagrams ladder diagrams are specialized schematics commonly used to document industrial control logic systems. Lecture introduction to plcs mme 486 fall 2006 6 of 47 advantages of a plc control system eliminates much of the hard wiring that was associated with conventional relay control circuits. The circuit also will not allow the operator to tie.
More extensive troubleshooting is now required within the identified faulty unit. Upon completion the technician will display skills in methodical. Determine whether or not voltage should be present between the following pairs of terminal block. How to do electrical troubleshooting of electrical motor. Notes on voltage range to expect when testing plc logic circuits. Troubleshooting and using circuit laws gaining circuit familiarity troubleshooting basics common troubleshooting techniques the program the practical troubleshooting of electronic circuits workshop will teach you how to recognise and efficiently troubleshoot common electronic component and circuit problems. Inputs pb2 figure 734 ladder logic program res output rto.
Plc troubleshooting can be performed in many different ways and as the. After successful completion, the troubleshooter can improve their understanding of dc, ac, three phase circuits, relays, contactors, plc, electronics, and other related technology. About 70% of the time is spent working, handson, at a troubleshooting station with motor control circuits operating at a safe, low level of 24 volts. Programmable logic controller 1, a program stored in the central unit of a. If you need to maintain and troubleshoot plc systems, this exciting new program will help you understand how plcs work and provide you. The designing, programing, testing, commissioning, troubleshooting, and maintenance of control logic are much easier using the ladder logic programs in a plc than in hardwired circuit. Electrical troubleshooting, plc troubleshooting training. Troubleshooting plc controls, circuits with plc simulator see more. Troubleshooting common electrical problems for industrial.
Introduction to programmable logic controllers plcs. The electrical problems start with basic electrical wiring, move up to plc examples. Handson experience with live circuits without the risk. Plc input and output troubleshooting all about circuits. Troubleshooting control circuits control circuits are generally designed so that an individual circuit controls only one function of a particular process or machine. No patent liability is assumed with respect to use of information, circuits, illustrations, equipment, or software described in this text. Plc program for latching and unlatching circuit plc latching and unlatching circuit this is plc program for latching and unlatched circuit for output. In this module, your professionals will diagnose and repair over 60 faults in each of three simulated circuits containing plc controls. At this post i will give some basic instructions which are from my personal experience in order to give you a guide for how troubleshooting in automation systems plc dcs is. If a problem should occur, the first step in the troubleshooting procedure is to identify the problem and its source. Included in this chapter are sensors, a separate study of safety. Cxprogrammer includes a wide variety of features to speed up the development of your plc program. Troubleshooting plc circuits tplc is the fourth in our series of simulationbased training modules. Most plcs incorporate light emitting diodes leds in their design, which offer a good source of diagnostics.
Optical isolation protects the backplane circuits by isolating logic circuits from input signals. An output circuit controls the output signal in the following manner. Troubleshooting a plc motor starter with jogging circuit. The plc has following basic sections are, processor section cpu the processor section is brain of plc which consists of ram, rom, logic solver and user memory. An input filter removes false signals due to contact bounce or electrical interference. Basic troubleshooting strategies all about circuits. The electrical troubleshooting examples may help sharpen your electrical installation testing skills. However, the controller circuits we devised for these two situations would.
The internal operation of a plc can be monitored via a handheld programmer, terminal, or personal computer, and many indicator lights are provided for io troubleshooting. Having an effective troubleshooting plan and following it can help obtain this feeling of satisfaction. This section of plc programming covers problems in industrial automation. Implement a safe circuit with hardware and software interlocking. If this is your case, you need to learn more about auto repairs. Design a plc program and prepare a typical io connection diagram and ladder logic. Oct 14, 2011 troubleshooting plc circuits simutech multimedia. Insufficient pilot pressure if dual stage valve check pilot and drain configuration. X l x c and r with the combination of these three values giving the circuits impedance, z. Understanding electricity and how to troubleshoot a circuit. Faulty cpu the best way to check for a faulty plc is to substitute a known good one to see if this corrects the problem.
Electrical troubleshooter for acdc circuits, relays, contactors and plcs photo credit. A virtual troubleshooting exercise such as this one is a good way to start students thinking in the right ways to becoming effective troubleshooters. Troubleshooting plc circuits develop the skills to troubleshoot electrical equipment and systems containing programmable logic controllers. Logic probes are useful tools for troubleshooting digital logic gate circuits, but they certainly have limitations. These circuits contain plc cpu, digital input module, digital output modules, dc power supplies, relays. A machine stopped working on me today whats happening is that a dosing unit isnt getting a signal to run there is a proxy sensor which detects cans and when it sees a can it is supposed to start the filling and no can then no fill. Lecture introduction to plcs mme 486 fall 2006 4 of 47 programmable logic controller a programmable logic controller plc is a specialized computer used to control machines and process. Fortunately, electrical circuit troubleshooting is an activity that works well for small groups of students to engage in as well as individual students. Sample pages from the workbook imagine having the answers to over 800 plc problems at your fingertips. Question 1 a chandelier has five light bulbs in it, and one of them is not working. Plc troubleshooting and diagnostics programmable logic controllers problems plc learn how to troubleshoot and diagnose plc s with this procedure and how to identify the plc problem areas. The ability to evaluate a students troubleshooting skills based on trouble shooting. First place the plc in standby mode so the output isnt activated. Plc basics and troubleshooting plc basics and troubleshooting course.
The intent of this article is to cover only the basics of plc troubleshooting, so there are some limitations on what will be discussed. The output bitswords are available to the inputs of the next rung of logic. Identify where the plc problem might be with certain inputs or outputs etc. The block diagram of programming logic controller plc is shown in above figure.
This software package will introduce the trainee to a proven system of troubleshooting. It seems to be natural to assume that most malfunctions of plc systems are due to processor problems, but in fact the opposite is true. Troubleshooting plc transistor output electronics forum. Electrical troubleshooter for acdc circuits, relays. If that pulls in its working then follow the power circuit to that coil to find what activated it and so on. Safe and effective troubleshooting of electrical systems is an essential skill for maintenance technicians in industrial, utility, or commercial settings. For instance, if a set is dead, you should start by checking power input to. For more information, refer to the holt cat electrical safety.
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