5 Common Mistakes to Avoid in PLC Programming for Industrial Automation


Programmable Logic Controllers (PLCs) have revolutionized the way industrial automation works by providing an efficient and reliable method of controlling machinery and processes. However, as with any technology, there are certain common mistakes that can occur when programming PLCs. These mistakes can lead to costly downtime, production losses, and even safety hazards. In this blog post, we will explore the top 5 common mistakes to avoid in PLC programming for industrial automation. By understanding these mistakes and how to prevent them, you can ensure that your automation systems run smoothly and efficiently, maximizing productivity, and minimizing downtime.


What is PLC Programming?

 PLC programming is the process of creating software programs for Programmable Logic Controllers (PLCs), which are used to control and automate processes in manufacturing plants, production lines, and other industrial applications. PLC programming involves writing logic and algorithms using specialized programming languages or graphical interfaces to sense the inputs and control the outputs of the PLC, such as sensors, actuators, motors, and other devices. The programming is typically done by automation engineers or control system designers who have a deep understanding of the PLC’s hardware and software components, as well as the processes and systems that the PLC will be used to control. The goal of PLC programming is to create efficient and reliable automation systems that increase productivity, improve product quality, and enhance safety in industrial settings.


Here are the 5 common mistakes to avoid in PLC:

 Mistake #1: Poor Planning

Poor planning can lead to inefficient programming practices, wasted time and resources, and ultimately, a system that doesn’t meet the intended requirements or specifications. Proper planning includes defining the system requirements and specifications, selecting the appropriate hardware and software components, creating a detailed program design, and establishing a testing and commissioning plan. Without proper planning, PLC programming can become disorganized and prone to errors. Therefore, it is essential to have a well-thought-out plan before starting any PLC programming project.


Mistake #2: Not Documenting Code

One of the most common mistakes in PLC programming is poor documentation of the code. Lack of documentation can make it difficult to maintain and troubleshoot the code in the future, and it can also make it harder for others to understand the program’s functionality. Proper documentation of the code, including comments, naming conventions, and clear logic, is essential for efficient and effective PLC programming.


Mistake #3: Ignoring Safety Requirements

Inadequate or ignored security measures in PLC programming can leave the system vulnerable to cyberattacks and other security threats. It’s important to implement proper security measures, such as password protection, firewalls, and encryption, to protect the system from unauthorized access and to ensure the integrity and confidentiality of data.


Mistake #4: Underestimating Debugging Time

Debugging is the process of identifying and correcting errors in the program code, and it is an essential part of PLC programming. However, debugging can be a time-consuming process, and programmers often underestimate the amount of time needed to debug their code. This can lead to delays in project completion and increased costs. To save time and resources in the long run debugging tools and techniques, such as simulation software or real-time monitoring, help make it more efficient.


Mistake #5: Neglecting Software Updates

Software updates are essential for maintaining the reliability, security, and performance of the PLC system. Updates often include bug fixes, security patches, and new features that can improve the functionality and efficiency of the system. Neglecting to install these updates can leave the system vulnerable to security threats, reduce performance, and limit the functionality of the system.



PLC programming is a crucial step for industrial automation. Most of the processes will be streamlined with the help of a well-planned and executed PLC program. Yes, the process makes the functioning easy and cost-efficient. However, if not taken these common mistakes into account, it might lead you to invest into extra resources and lose some of your precious time. So, next time when you are diving into the process, keep this blog handy and go with ENWPS to tick all the right boxes.

Talk to us today! Reach us on automation@enwps.com


Programmable Logic Controllers (PLC): The Concept and Benefits of PLC Programming


Programmable logic controllers (PLCs) are a type of computer system used to automate and control industrial processes. They are designed to be easy to program and offer numerous advantages over traditional hardwired systems. They are used in a wide range of industries, from manufacturing to robotics, and provide many advantages over conventional hardwired systems. Let’s discuss the advantages of PLC programming, the components of a PLC system, and the benefits of PLC programming. With the help of this blog, we will also explain the concepts and benefits of PLC programming.


What is PLC Programming?

The process of developing internal logic for a programmable logic controller is known as PLC programming (PLC). PLCs are often programmed in a “language” exclusive to the controller; this translation from spoken word to something the controller can understand and execute is correctly explained.

The primary purpose of a PLC is to provide a reliable and efficient means of controlling and monitoring automated processes. It is a computer-based system that uses a series of instructions to control the operation of a machine or process. It is designed to be a cost-effective and reliable alternative to hardwired systems. PLCs are used in a variety of industries, from automotive and aerospace to food and beverage manufacturing.


Advantages of Using PLC

There are many advantages to using a PLC system in industrial automation and control. The main benefits of PLC programming include the following:

  • Increased efficiency, improved safety, and greater flexibility.
  • Easy to program and capable of performing complex operations with minimal effort.
  • They can also be programmed to execute sequences of instructions, allowing for more complex tasks to be automated.
  • The programming code is stored in the PLC, making it easy to update the instructions.
  • Provide a greater level of safety than traditional hardwired systems.
  • They are robust and reliable, meaning they are less likely to fail than traditional hardwired systems.
  • PLCs offer greater flexibility than traditional hardwired systems. This allows them to be used in a variety of different applications.


What are the Components of a PLC System?

The main components of a PLC system include a

  • Programmable logic controller,
  • Input/output interfaces,
  • Power supply, and
  • Programming software.


How do PLC Systems Work? 

The PLC itself is the main component and is responsible for taking input from sensors and executing the instructions programmed into it. The input/output interfaces allow the PLC to communicate with external devices such as sensors, switches, and relays. The power supply provides the electricity needed to operate the PLC. Lastly, the programming software is used to create the instructions that the PLC will execute.

The PLC can be programmed using a variety of programming languages, such as ladder logic, function block diagram, sequential function chart, structured text, and instruction lists. Each of these languages has its own advantages and disadvantages, so it is crucial to choose the language that is best suited for the task at hand.



If you are looking to improve the efficiency, safety, and flexibility of your industrial automation and control processes, PLC programming is a great option. With the right PLC programming services, you can unlock the full potential of your PLC system. Needless to say, PLCs have transformed automation in industries and are constantly evolving. As technology evolves and add newer versions of connectors, software and hardware, PLCs have the flexibility to adapt and update. While everything around is changing, keep in mind to choose an appropriate PLC programming service that serves your purpose well and gives you an upper hand.


How to Program a PLC: A guide on how to get started programming a PLC and HMI


HMI, or Human Machine Interface, is growing its presence and is entering our daily lives in the most silent way possible. You might not realize, but we are already using an HMI every day. The best example of that is bank ATMs. You can use the machine to dispense a certain quantity of money or to deposit money using the screen and push buttons. In an industry, HMIs play a more significant role by enabling personnel to monitor machines and operate them in an automated way. But how can we couple PLC and HMI, and how has it benefited the process of automation and increased efficiency? Let’s decode them one by one, starting with a PLC overview and an HMI overview. Let’s dive in:


What is PLC? 

A ruggedized computer called a PLC, or programmable logic controller, is used in industrial automation. These controllers have the ability to automate a particular procedure, a machine feature, or even a whole manufacturing line. PLCs are helpful instruments for repetitive operations because they can collect data and don’t have any mechanical parts.


What is HMI? 

A Human Machine Interface, or HMI for short, is a tool that enables a human to communicate with the PLC managing the manufacturing process and receive feedback from it. In other words, it is a way for you to instruct your devices and receive updates on their progress.


How to Program a PLC?

For the purpose of debugging and increasing efficiency, many HMIs may also link to PLC logic and display it on the screen. Compared to constantly connecting a computer or laptop, this can save significant time and effort. Together, HMIs and PLCs monitor and manage the machine. This implies that they must get along and, in a sense, speak the same language.

There are five easy steps to program a PLC to achieve the highest efficacy and for the HMI and PLC to be able to communicate with each other:

  1. Define the task
  2. Define the inputs and outputs
  3. Develop a logical sequence of operation
  4. Develop the PLC program
  5. Lastly, test the program

Once you’ve tested the PLC and added the required commands, all you have to do is establish a viable connection between the PLC and HMI so that the data is ready to be displayed. This is achieved by doing it on a “protocol.” Modbus, Ethernet/IP, and Profibus are popular protocols. All of these are just industrial networks, which can be easily found on each manufacturer’s website. After that, anything that is programmed into the HMI can be used to monitor and control PLC functions.


Why is it Important to Program a PLC?

PLC programming has enabled industry operations to work seamlessly and monitor machines with more efficiency. Here are the reasons why it is important to program a PLC:

  • Improves accuracy and reliability and reduces system malfunctions.
  • PLCs are capable of a wide range of complicated jobs that PC systems cannot.
  • PLCs make it possible for you to spend less time and money upgrading or updating hard drives while also better preparing for your charter.
  • They simplify vessel monitoring and work at lightning speed.


HMI vs PLC: What are the differences?

There are some significant differences between HMI and PLC programming, which set them apart and enable companies to best utilize them. Here are the key differences between HMI and PLC:

  • In a PLC, the logic must be written, whereas, in an HMI, the logic view must be designed.
  • In contrast to PLC, where the parameters must be configured in order to perform the programme, HMI allows you to adjust and monitor the settings.
  • As opposed to working with libraries, hardware configuration, network setup, and other advanced tools in PLC, you can design and use audit trails, reports, trends, printouts, and other advanced tools in HMI.
  • The HMI can be compared to the eyes and the PLC to the brain.



HMI-PLC combo units are advantageous for more straightforward applications because they are less expensive, require less time to design, and occupy less panel space. The separate PLC and HMI solutions will improve efficiency and accuracy and leave little to no room for system malfunctions, saving you money and reducing stress.


The Pros and Cons of Outsourcing your PLC Programming Projects


Contrary to popular belief, outsourcing tasks in an industrial environment is not a recent phenomenon. The trend began, albeit in a small way, in the 1970s as the concept of core strength forced companies to rethink on doing everything on their own. Today, outsourcing has become common and covers many activities and areas of a company’s operations, including a few that were once considered as very critical to the core strength. So, it is no surprise that even PLC programming is today outsourced by many companies, who prefer to entrust professional agencies with the task, and in the process, use their own resources for more productive purposes. Such companies view outsourcing as a win-win situation, even as there are those who are sceptical and have serious reservations on leaving such important tasks to outsiders.

So, what exactly is the ideal thing to do when a company faces this dilemma whether to outsource a particular activity of their operators? It will be worthwhile to examine the issues at length before arriving at a definite conclusion.


What Are the Pros of Outsourcing Your PLC Programming Projects?

There are two sides to any argument. Outsourcing of PLC programming certainly has its advantages and a few of them are elaborated in the following paragraphs.

Access to a larger pool of talent – With all the technology developments and online resources, PLC programming is not a rocket science anymore, but the fact remains that it is a skilled job that is also time consuming, and any error only loses more time. Skilled programmers are expensive to hire, and a company may not have enough jobs for employing them full time. Outsourcing provides a better option and gives access to a larger talent pool and assured programming success, with experts who have accumulated years of experience in doing similar tasks.

Cost savings – In outsourcing, a company pays only for the time the programmer works on its project, unlike a full-time employee who may not have enough work. So, companies not only have access to a larger pool of experts through outsourcing, but also save money in the process.

Increased efficiency – Professional agencies that execute outsourced projects know exactly what is to be done and get on to the job immediately. Their experts are conversant with all types of machines, PLCs and in general the tasks they are required to do. They bring efficiency to the table.

Faster turnaround time – They are paid based on specific tasks or projects and since they have many such assignments going, they usually work round the clock and complete the project well on time or even earlier, ensuring a faster turnaround time.

Focus on your core business – This is what started the outsourcing trend in the first place – so companies can deploy their manpower and resources for more productive activities while experts handle the technically intricate and exacting job of PLC programming which is best handled by experts.

Cut down on training and support costsFinally, it again comes down to paring costs – in-house programming staff needs to be trained and supported in whatever way their functioning needs to be supported in terms of support services, upgrades, etc. With outsourcing, all such nitty-gritty is automatically taken care of.


What Are the Cons of Outsourcing Your PLC Programming Projects?

Having seen the advantages of outsourcing the PLC programming, there is the other side, the disadvantages one must consider before making the decision, and here are the main points:

Language barriers Humans communicate through speech and language is often a barrier, not only internationally, but also within a large country like India. Even a mispronunciation can cause errors in, and PLC programming has no tolerance for errors. (Programming is done by reading the functional description documents and rarely based on verbal things)

Time zone differences – The world may have become a global village digitally, but it is still divided across time zones and that could pose additional problems in communicating in real time in case of problems and troubleshooting by remote in case of any urgent requirement.

Lack of control – There is always the issue of how effectively a company can control its operations when it depends on outsourcing for critical requirements. What happens in case the agency is unable to deliver, or worse, leaks or loses data?

Limited flexibility – Even as outsourcing is not without merits, when it comes to operational requirements, there is no flexibility when activities are outsourced. There is a contract and understanding, and the agency may well deliver as agreed. But for any immediate requirement, it will still have to wait for the right time zone or the person being available when most needed.


What Are the Costs Involved in Outsourcing Your PLC Programming Requirements?

This is a tricky situation, as in any cost calculation; there are often hidden charges that are not obvious initially. Outsourcing comes at a cost, but then doing the same activity in-house also has a cost. Does it make more economic sense to hire a programmer on a full-time basis? Is there enough work for a full-time employee? But then how advisable it is, to have just a single employee for a critical function like programming? What if the person leaves without notice having polished the skills? Ideally, companies recruit a team or start a department for critical jobs, not hire a lone expert. So, any cost calculation of outsourcing the PLC programming must factor in all the costs of doing the same job in-house. Smaller companies usually do not have enough work to justify full time experts for certain jobs. Larger companies may well have enough work, but still must do the cost benefit analysis to find out if the same job can be outsourced without losing efficiency if there is a cost advantage. So, at the end of the day, outsourcing must be a well-considered decision as there are issues that go beyond the visible cost.


How to Find the Right PLC Programming Company?

The first step when looking for outsourcing the PLC programming task is to understand the requirements, what the company wants to accomplish through outsourcing. Better still, make a list of the exact requirements about the type and make of PLCs it has, the machines or equipment which are connected to it, the process or functions that are monitored, the total number of I/O points, programming language, etc. Next is to prepare a shortlist of three or four companies that are known to offer their services who are well known in the market or recommended by peers or consultants. It is very important to check their credentials, find out how long are they operating in this field, their familiarity with all the leading brands of PLCs and other hardware/software, the programming languages, and the type of work they have handled, their track record as evidenced by the number of companies they are working with. Also, whether they have specialized expertise in handling advanced automation needs, have engineers from all disciplines and the kind of projects they have handled, and the willingness to deploy time and resources. Finally, it is important to put all the requirements in the contract and have a clear statement of the deliverables with timelines and other requirements in terms of emergency support, etc. This is a lot of work to do, but essential to ensure a smooth working relationship with the best PLC programming company chosen from the shortlist.



Having examined the issues at stake, looking at the pros and cons, outsourcing PLC programming projects can make sense for most companies, especially the MSMEs, who must make the best use of available resources. A professional outsourcing firm specializing in PLC programming can help such companies with well-executed industrial automation projects that help companies to overall success. Even large companies who have enough resources often resort to outsourcing today thanks to the many advantages that accrue from it, rather than retraining their in-house programmers every time a new device or technology comes to the market. Well established firms like ENWPS have over two decades of field experience and hundreds of programming years collectively from their experts are ideally positioned to deliver the best results, creating a win-win situation.


How PLC Programming Can Help Scale Your Manufacturing Business


A PLC – Programmable Logic Controller – is a tiny, rugged computer used in industrial automation. Though the CPU of the PLC is not as versatile as the one used in PCs for regular use, it is extremely fast for the tasks it is designed for, and unlikely to slow down in operation. The key to successful automated plants or process industry operations is in programming the PLC correctly. The 5 languages popularly used for PLC programming – Ladder Diagram, Sequential Function Charts, Function Block Diagram, Structured Text and Instruction List – are all part of the IEC Section 61131-3 Standard. This IEC Standard allows some ground rules that standardise PLCs and their languages. Each language has its pros and cons, and some PLC manufacturers have also evolved their own language for their PLCs. The programmer must be familiar with the PLC program syntax – which is how the program is written, the codes and the symbols used. An incorrectly programmed PLC can result in costly downtime and can even cause damage to the equipment or the plant.


How PLC Programming Can Help Scale Your Manufacturing Business

PLCs have been in use in industrial automation for over 50 years and have proved to be cost-effective and reliable in automating systems and processes. Before the PLCs, industrial machines were controlled by a huge array of relays, hardwired in a very specific way. PLCs replaced the cumbersome relay system with electronic solid-state control. A modern manufacturing plant comprises several machines that form an assembly line or a manufacturing cell, each having a specific role or function, and operate in a sequence to complete a cycle of operations. For example, a piece of sheet metal may pass through a cutting machine first, before entering a bending machine and then go to the drilling machine and end up with a grinding machine to metamorphose into a panel for mounting switches. This is an automated operation where the part moves through four machines automatically through conveyors without any human intervention, getting cut to size, bent at certain angles, holes drilled at appropriate places and finally rough edges are ground smooth. This entire operation is facilitated by the PLC, which has been programmed to follow the sequence and the time cycle, based on the trials taken to perfect the sequence. This process of automating production is what helps industries scale up their manufacturing business, by applying it to each machine and function, the machines together forming the production cell or assembly line.


How PLC Programming Can Help Automate Certain Processes

A typical manufacturing unit today is a combination of human efforts and mechanization. For example, in automobile manufacturing, the assembly of individual parts like engine and gearbox may involve human labor, but operations like the welding of the chassis and painting of the car after assembly are mechanized and fully automated. These tasks are performed by robots, which are also synchronized to perform in the desired sequence through PLCs. Increasingly, artificial intelligence or AI plays a role in such complex tasks. The role of AI in manufacturing is on the increase, as it becomes more data driven, the data collected during machine operation and analyzed to gain more insights. These insights help optimize the processes further.


Today most processes in the manufacturing industry can be automated by using a series of workstations linked by a transfer system operated by robotics and control systems. It must be understood that repetitive tasks are mostly automated, and the sequence of operation is well known and understood, which forms the basis for programming of the PLC. Each workstation performs a specific operation, and the product moves forward progressively until the task is completed and the final product is ready. For example, in a bottling plant, empty bottles are picked up automatically from the crate, arranged on the conveyor system where they are first washed automatically at one workstation, dried at the next, filled with the appropriate content, capped, labelled and finally loaded in crates, ready for dispatch, without any human intervention. All these are repetitive operations, and can be programmed in a PLC, which receives signals from input devices, such as sensors and switches, and based on the logic program, activates output devices like motors or other machinery. The role of human workers in such an environment is to just supervise and monitor the operation and intervene only in case of sudden stoppage of the machine, to initiate corrective action.


PLC Programming: The Key to Better Manufacturing?

The PLC is at the heart of the automation system in the manufacturing environment and programming determines how it works in operation. This means PLC programming is the key to better manufacturing. The PLC basically has a few important components – the CPU, I/O modules, rack and power supply. The CPU is the brain of the PLC which does all the calculating and works at an extremely high speed. The I/O or input/output modules connect the field inputs (basically sensor data) and outputs (signal for devices that produce actions for movement of machinery). The rack facilitates the data exchange between the CPU and the I/O modules, and the power supply does what the name suggests – provide energy. Programming is what makes this entire operation work in a predetermined sequence – read the machine parameters, provide the inputs, and based on the operational requirements, and let the CPU take corrective measures that are transmitted as output for appropriate action. Parameters like temperature, pressure, speed, etc., of the machinery are thus controlled and kept within specified limits for safe and trouble-free operation without any stoppage or breakdown. There are hundreds of such operations performed in a typical manufacturing plant, and the programming of the PLC is what keeps the plant running smoothly which in turn facilitates better manufacturing operations.


Pros and Cons of Outsourcing your PLC Programming Projects

More and more companies today are automating their operations. Apart from new factories and manufacturing plants that start with automation, almost all legacy plants are also undergoing modifications and upgrades, automating many if not most operations. This has resulted in great demand for software and coding specialists, and consequently creating the need for outsourcing certain requirements. PLC programming is a skilled task and involves hours and hours of coding, which is getting even more complex in the age of IIoT and connected plants, with data driven decision making and use of artificial intelligence and machine learning algorithms. So what are the advantages and disadvantages of outsourcing such a critical task?


One of the main benefits of outsourcing is that companies get a depth of expertise that is rarely available in-house, and even if one tries, such talent comes at great cost, which the volume of work may not justify. Outsourcing companies are staffed by experienced industry professionals at the top, and programming experts at other levels, a combination which makes for swift execution, which together with the cost advantages works highly in favour of the company. The trend of outsourcing is not new; it has been perfected over the last two decades so today the outsourced companies understand the product development cycle. Backed by their experience of doing similar tasks over a long period, they also understand the users’ needs and are able to deliver what is exactly asked for. Moreover, today the cost of communications is minimal and modes multiple, so remaining in constant touch to resolve issues as they arise is no longer a problem. Companies large and small can benefit from outsourcing in view of these advantages.


There are of course some disadvantages in outsourcing, the foremost being the risk of cybersecurity breaches and compromising the intellectual property. Not all outsourced organizations have the professional integrity to allay all such fears. The other major concern – poor quality of work – often results from wrong choice or inadequate checks during due diligence. One should however be cautious when outsourcing about the cost, and insist on transparency on that front, lest there be hidden costs which could make the project very expensive! Also, not many outsourced companies have the credentials to undertake challenging tasks. A little less common, though by no means negligible, is the problem of cultural incompatibility in the age of globalization, where certain geographies may be less amenable to sharing such working relationships.



Successful businesses today are thriving on automation and more automation. The Covid pandemic and the resultant lockdown that shut down most businesses also brought home the fact that those businesses that were high on the automation adoption curve could face the lockdown with lesser disruption, with minimum manpower. Automation in the manufacturing business relies on machines, which in turn are operated with the help of PLCs. As more and more businesses choose automation to run their production lines, PLC programming will be their critical link to improved productivity. However, companies that are just embarking on their automation journey may well tread cautiously, and consult with professional agencies, both about the feasibility of going in for automation, and the ways to implement it. In an era of specialization, it is difficult for enterprises to have all the talent in-house. Automation, robotics and digitalization are words often used today, but not all businesses can profit from the high capex that these technologies need. At the same time, it is not possible to scale up without adopting modern methods. Professional expertise can guide companies in this endeavour.


ENWPS has a two-decades legacy of providing innovative Automation and Robotics solutions – from concept to implementation, providing quality and comprehensive innovative systems coupled with technology expertise.

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