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How to troubleshoot with a PLC

How to troubleshoot with a PLC is the most common practice.

PLC Technician

Troubleshooting PLC itself is a much less common practice. As PLCs are so reliable. PLC (Programmable Logic Controllers) where designed specifically to be more reliable thank a computer, and more simple so a maintenance technician could work with them, including use them to troubleshoot the machine and automation control process.

The PAC (Process Automation Controller) on the other hand is much more complicated as it is a customized industrial computer, designed with computer IT and programmers in mind, not the maintenance technician or electrician. Likewise, the PAC is a lot less useful for troubleshooting machines and automation control systems. Actually, in that respect, the PAC is the opposite due to its complicity. It is more common end-users (process and manufacturing maintenance personnel)  will be troubleshooting the PAC itself more than using it as troubleshooting tool for the machine. Read on to learn why…

Given that PLC vendor’s intent was to make the PLC easy for the maintenance electrician to use, beyond just using ladder logic as programming language, the added many great software tools to aid the maintenance electrician in troubleshooting machines. You wont find most of these PLC troubleshooting software tools and design features in a PAC. Below are just a few examples. At the end of this article will be a link to read about more. To learn about all of the PLC troubleshooting tools and techniques, and to master PLC troubleshooting, there is currently only one way, attend a hands-on PLC Troubleshooting Training Seminar in St. Louis.

How to troubleshoot with a PLC | Basics

In the real world, 99% of the time, the problem with a machine or process is not the PLC, it is an Input or Output. In other words, it is one of the hundreds of sensors, switches, solenoids, etc. gone bad, out of adjustment or not be made. If the people who wrote the PLC program used PLC programming best practices, the PLC program will be well documented ladder logic. (A symbolic programming language as easy to troubleshoot as looking at a ladder and seeing what rung is broke on the ladder. )

Given the above, based on symptoms reported, you search PLC program for the input or output not working, then trace back through the ladder logic to find out what contact is not being made and that is the sensor or switch causing the problem that you need to look at out in the real world. most of the time that is how you troubleshoot with a PLC, simple as that and takes about 4 minutes to find root cause. (If you have been properly trained by BIN95.)

But … in real life it is not always simple, just most of the time with a PLC. There can be intermittent problems, analog problems, poor management of automation equipment in your facility, etc.

FYI:  Management of PLCs in your facility is also taught in BIN95 PLC Training seminars.

Those little more complex PLC troubleshooting instances that occasionally come up is where PLC troubleshooting software tools that vendors provide, come in. Read How to troubleshoot PLC Allen Bradley to learn more. Below are a few excerpts…

For more cumbersome troubleshooting like intermittent problems, RSLogix 500 has great tools like the Histogram, Custom Data Monitors, trend charts, writing your own diagnostics rungs using Latch bit, etc.

Rslogix 500 Custom Data Monitor    RSLogix 5000 Trend Charts

One example of real world troubleshooting we teach, which is not in books or software, is using RSLogix 500 program “Compare Tool” (Compare Tool may be in your version of RSLogix 5000, or as a separate software for PACs. Or you might not have the tool if you are using PACs, instead of PLCs to control your machinery.) Those not spending years maintaining a PLC/PAC controlled facility may not be aware of the common scenario of one employee on one shift changing the program, and the rest don’t know it. If the troubleshooter suspects that, they can use the program compare and once again within about 15 minutes, find the problem.

PLC Troubleshooting tool

System Data Tables and other data tables found in a PLC (like RSLogix 500) are great troubleshooting tools too, but are not in PACs (like RSLogix 5000). This is another major factor contributing to the use of PACs resulting in increased troubleshooting and downtime. In BIN95’s instructor based PLC training, we also teach best practices in writing PLC programs, so attendees can identify if they are being used before purchasing new machines or systems controlled by PLCs. (Like RSLogix 5000 programmer compensating for missing data table files in their tag naming conventions, for example.) Having a program that was written using PLC programming best practices, with the end user in mind (customer who has to maintain equipment for the next 10-20 years), greatly reduces troubleshooting time. … continued at https://bin95.com/rslogix-5000-troubleshooting.htm

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July 24, 2017 Posted by | Education, Electrical, maintenance, manufacturing, PLC, PLCProfessor, Skill Shortage | Leave a comment

Bug free PLC programming example – 21 CFR Part 11

Source: PLC programming examples under GMP GAMP 5

PLC programming example

GMP (Good Manufacturing Practice), GAMP 5 (Guide for Validation of Automated Systems), 21 CFR Part 11. IEC 25010

Best practices in the PLC programming realm, uses Static Analysis (verification testing). It is probably one of the least covered in PLC training, and therefore least practiced. (With those receiving BIN95 PLC training being an exception to that rule as they have always covered it in the instructor based classes since 1995.) Yet it should be one of the most important parts of the automation control design phases.

See 5 reasons why static analysis of PLC programming is very important.

The most important being Safety, Maintainability and Cost Savings over the life cycle of the equipment that PLC code controls. Many machine designers and system integrator claim they do not have the budget to do static analysis to GAMP 5 level of quality. The cost of not doing so, is passed on to you (the end-user of the equipment) for the life of the equipment.

That cost to end-user, when measured in using TDC (True Downtime Cost), can and often is … astronomical over the life of the equipment.

March 23, 2017 Posted by | Education, Electrical, engineering, maintenance, manufacturing | , , , , , , , , | Leave a comment

OPC for SCADA and DCS training

What does OPC stand for? OPC = OLE for Process Control

What does OLE stand for? OLE=Object Linking and Embedding

opc-training

OPC communication protocol is the most current to standardize data transfer between all industrial devices. Which make OPC training essential to those working with IIoT.

(IIoT=Industrial Internet of Things)

For OPC SCADA and DCS, this OPC training and software gives you real world experience on free OPC server.

Source: OPC for SCADA and DCS training

February 7, 2017 Posted by | Education, engineering, manufacturing, PLC | , , , , , | Leave a comment

Online MCC Electrical Training

This online motor control center training certificate course for beginners.

Source: Online MCC Electrical Training It is also great for a refresher. Below is a little video tour and demo of the MCC electrical Course…

December 16, 2016 Posted by | Education, Electrical, engineering, maintenance, manufacturing, safety | , , , , , , , , , | Leave a comment

Mechanical Engineering Educational Newsletters

Volume 1, 1st Edition:

A 6 page Mechanical Engineering news letter touching on …

mechanical-engineering-pdf-1e1

  • Protecting bearings from dust.
  • Open trickle chutes for damp bulk product.
  • Changing the service duty of a pump.
  • Flange bolting-up practices.
  • Maintenance costs capital moneys.

Each topic covers basics of mechanical engineering from a real world application perspective by a leading ME in the industry, Download Mechanical Engineering PDF now.

October 20, 2016 Posted by | engineering, maintenance, manufacturing, Mechanical, Skill Shortage | , , | 1 Comment

Siemens PLC Simulator and Plant Simulation Software

This Siemens PLC Simulator and Plant Simulation Software bundle make for a great Siemens training tool.

Source: Siemens PLC Simulator and Plant Simulation Software

Siemens PLC Simulator and Plant Simulation Software bundle, hands-on training tool in a more safe and productive environment. Build your own plant, write your own PLC programs, run the simulation of all.

August 25, 2016 Posted by | Education, Electrical, engineering, maintenance, manufacturing, PLC | , , | Leave a comment

SCADA Basics course using Siemens automation WinCC as tutorial

scada tutorial - simatic,wincc siemens automation.

SCADA Basics Course is also 1/2 the PLC and SCADA Certificate course. The brand used in SCADA tutorial Siemens automation WinCC. Also covers in depth, industrial network security. 4.2 CEUs

Most who view the source page below click on the link to view SCADA Basics Course sample PDF, once they get there.

Source: SCADA Basics course using Siemens automation WinCC as tutorial

Be sure to share with others, they might appreciate it.

June 5, 2016 Posted by | Education, Electrical, engineering, maintenance, manufacturing, PLC | , , | Leave a comment

Industrial Automation Technician Training

With this Industrial Automation Technician Training Bundle of technical certificate courses, you save 32%! The Industrial Automation Specialist Training bundle includes the 7 following certificate course software topics. PLC training, PAC, HMI, VFD, motor controls trainer, troubleshooting trainer and the DeviceNet tutor.

Source: Industrial Automation Technician Training

Automation Technician Training

7 Certificate courses (CD or Download format available)

February 18, 2016 Posted by | Education, Electrical, engineering, maintenance, manufacturing, PLC, safety, Skill Shortage | , , , | Leave a comment

Industry 4.0 in USA: Risk

Industry4-0-Launch

Is USA ready for Industry 4.0 and its components like IIoT?

Implementation of Industry 4.0 in the USA come with the greatest risk. This article is a must read.

Source: Industry 4.0 in USA: Risk

January 22, 2016 Posted by | Education, Electrical, engineering, maintenance, manufacturing, PLC, safety, Skill Shortage | , , , , , , | Leave a comment

PLC Training Courses

PLC Training Courses. Last one for 2015, location St. Louis, MO. Date: Dec 1-3

^^^ Click to learn more.

August 24, 2015 Posted by | Education, Electrical, engineering, maintenance, manufacturing, PLC, Skill Shortage | , , | Leave a comment

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