#plc programming tutorials for beginners

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What is a Redundant Power Supply and How Does It Work?

The electrical components inside enclosures that house industrial automation systems like PLCs often operate on a 24 volt power supply. So in these enclosures we usually need one or several power supplies that each have a 24 volt output voltage. But in some applications where ultra-reliability is essential, and an unexpected loss of power would be disastrous we need to use “redundant power supplies”.   In this video we’re going to learn exactly how these types of power supplies work from a practical perspective.

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How to Wire a Profibus Cable to a Profibus Connector

Profibus is a widely used communication protocol for Siemens industrial applications. If you did not purchase a pre-wired Profibus connection or one was not provided for your application, you made need to wire one yourself.

In this video we are going to discuss what tools are needed for wiring the Profibus connector as well as the different steps required.

We will talk about what the different layers of the cable are called and how to strip those layers to get to the core wires required for the connector.

Go ahead an watch this lesson to learn how to wire a Profibus connection cable.

Below are the links for the Siemens products we mentioned in this video.

Profibus Cable: https://mall.industry.siemens.com/mall/en/us/Catalog/Product/6XV18300ET20

Profibus Connector: https://mall.industry.siemens.com/mall/en/ww/Catalog/Product/6ES7972-0BA52-0XA0

Profibus Fast Connect Stripping Tool: https://mall.industry.siemens.com/mall/en/ww/catalog/product/6gk1905-6aa00

Read the transcript

When you're going to connect your PLC to remote I/O or any other device in the field using the Profibus network, you need to make use of an RS-485 or a Profibus cable. But to be able to connect the cable to the PLC or any other device on each end of the network, you first need to connect the cable to a Profibus connector. In this post I'm going to show you how easy it is to do that.  

Here I have a Profibus cable and a Profibus connector. We ordered this cable from the Siemens and if you're wondering about the order number, this is the order number that you can use to order the same cable if you need to use that in your Project. Just Google the order number and the link for the Siemens site pops up in the first few results.

Now this is the product information for the cable I'm currently using in this video. As you know, cables are sold by the length. As you can see here, with this order number, the length for the cable you receive will be 200 meters which is about 650 feet. So if you need a different cable length for your project, you may want to consider a different order number when placing your order. Now where can you find the order numbers for different length of this cable? For that you can click on this link here on the top of the page which says Profibus bus cables.

Here in this page you can see a list of order numbers for the same cable but with different lengths. For instance with this order number, the cable length will be 20 meters which is about 65 feet or with this order number the length for the Profibus cable will be 50 meters or 160 feet. So depending on the project requirements, you can select a different order number when placing your order.

I'm also holding a Profibus connector in my hand. This is the order number for this connector. Just as you did for the cable, you can Google this order number if you want more info on this module.

We will put a link below this video to the Siemens website for both the cable and the connector. Now let's see how you can connect the cable to the connector.

Here we have a Profibus cable that we are going to connect to our DB9 Profibus connector.  In this video I am going to show you how to do this. The items that I am using for this task are a DB9 Profibus connector, a Profibus cable, a utility knife, a screwdriver, and diagonal pliers or wire cutters.

The Profibus cable is a shielded twisted pair. We describe the outside as the outer sheath, followed by a braided shield, a foil shield, an inner sheath, and 2 single core wires, one green and one red.  

The first thing that I need to do is to strip the outer sheath or the purple plastic outer cover. I’ll measure about 2” of cable which is approximately 2/3rds the length of my index finger. I’ll begin stripping the outer sheath by carefully scoring the plastic with the utility knife. Under ideal circumstances, I would use a Profibus Fast Connect stripping tool to strip the Profibus cable but in a pinch, I’m using a utility knife. You may use that or any other appropriate tool that you may have available. I’ll cut around the entire sheath being careful not to cut too deep into the cable and continue scoring the plastic until I’ve have cut entirely through sheath.

Now that I have cut around the outer sheath completely, I need to make a cut from the scored area to the end of the cable. I carefully use the utility knife to cut the outer sheath from cut section to cable end ensuring that I don’t cut too deep and damage the single core wires.

I have the utility knife and cabling oriented this way and I am cutting away from my body to minimize the possibility of injury.

I will probably need to make a few passes in order to completely cut through the outer sheath. Once I think that I have cut through, I am going to try to remove the outer sheath.

If you are unable to remove it, go back and continue to cut until you can successfully remove the outer sheath to expose the next layer of cabling which is the braided shield.

In order to remove this layer I will use the wire cutters and begin clipping the braid at the cut end.

Once a small section of the braid has been clipped, it may be easier to gather the remaining braid to clip it near the stripped end piece.

Continue to clip the braid all the way around the cable until you have removed as much of the exposed braid as possible.

Once the braided shield has been removed, I’ll use the utility knife to score the foil shield to remove it. The foil is fairly easy to remove and won’t require much effort.

Once the foil is removed, you will see the inner sheath that is fairly rigid.

I will use the same technique that I used while removing the outer sheath.

I’ll cut around the entire circumference of the inner sheath until I expose the single core wires. Use more caution during this step as this is the last protection for the wires.

Once I have completed the cut, I remove the inner sheath to expose the wires.

As described previously, here we have two single core wires, one green and one red. Separate the wires slightly in preparation for placing them into the Profibus connector.

I’ll open the connector and you will see that the internals consist of two cable connection paths.

Above the cable opening holes in the bottom of the connector, you will see two plastic tabs. These tabs, when pressed closed, will pierce the wires sheaths as well as hold them in place.

While the connector is held with the cable holes at the bottom, I gently lift the plastic tab on the left to expose the wiring mechanism which will hold both of the wires.

Use caution so as not to break the tab while lifting. With the tab up, I’ll place the green wire in the left side of the mechanism and the red wire in the right side.

Once I have both wires in place, I’ll close the plastic tabs. I apply pressure to the tab to ensure that the wires are held firmly in place and the piercing spikes penetrate the wires sheaths.

I’ll grasp the cable and route it through the cable hole on the left side of the connector.

Once the cable is properly routed, I’ll close the connector and make sure that there is no interference caused by the cable.

I secure the connector closed with the embedded screw and my screwdriver. Make sure you don’t tighten the screw too much as this may break the connector.

Well that’s it, that’s all there is making a Profibus connection. If you found value in this video, be sure to like us and as always, feel free to comment below.

Did you find this video helpful? Well we have many more instructional videos for your viewing pleasure. Be sure to subscribe to the RealPars channel on YouTube. Subscribing ensures that you are notified when new content is available. Thanks for watching!

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5 CRITICAL TIPS THAT CAN GET YOU A JOB AS AN PLC PROGRAMMER

Working as an automation or controls engineer is one of the most attractive and high paid jobs in the marketplace. As an automation engineer, you have the opportunity to design sophisticated control and monitoring systems in some of the most strategic and important industries (such as oil, gas, and steel). This greatly increases your social status and who doesn’t like high social level jobs?

But in the case that you are looking for a job in this field and you’re a new graduate or just someone who likes to work in this field but doesn’t have the relevant experience, you may find it difficult to find a job. Most of the job advertisements you see around require at least two years of relevant experience.

I’m here to tell you that this is not a problem, it’s an opportunity! Why? Because in this situation most people are not really committed towards acquiring a job in the field and so they give up after applying for one or two jobs. They get preoccupied with other non-relevant job and leave the opportunity for those who know the true value of working in this field and are committed to becoming an automation engineer. It’s this mindset that helped me find my ideal job as an automation engineer (or PLC programmer) when I had no real experience in this field.

I now have more than six years of experience in designing control systems for big industries such as oil, gas, petroleum, and steel. After only two years in the first company that I was working for, I was promoted to the head of technical department where I have had the luxury of working with some of the most talented automation engineers from all around the world. Most of them had a long extensive background in this field.

The YouTube channel I started in collaboration with some of my colleagues is now one of the most viewed channels in the field of industrial automation training. We also created a library with practical PLC programming courses, which is one of the “most effective and practical training courses,” according to other automation experts.

While all this is amazing, when I was just starting out in the field, nothing was this good. Although I used to work harder as an electrical technician in companies who manufactured electrical enclosures during high school and colleges, I had no real experience in programming and designing industrial control systems. As you may guess, most of the job opportunities that were available required real experience in this field. But I didn’t give up because I couldn’t. I had invested several years during high school and college to become on automation engineer. It had been my dream job for so long that I couldn’t simply turn a blind eye to it.

I’ve recently received a lot of questions, both online and offline, asking me how to get a job as an automation engineer or PLC programmer without any experience in the field. While I prefer to answer every query that comes in, my schedule has been very tight lately and unfortunately I can’t respond to every question that comes in.

Because of this, I’ve decided to share my personal experience as someone who searched for a job in this field and as an employer who reviews resumes, interviews candidates, and hires automation engineers for a variety of projects.

So let’s get started!

1. Put yourself ahead of the crowed by educating yourself as much as you can.

When I graduated from college with a Bachelor of Science in Instrument and Control Engineering, I found out that there are a lot of people like me holding the same degree that I do. And a few of them had applied for some practical training programs on the top of the college curriculum. So although I was not in a good financial situation at that time, I invested most of the money I earned into the different training courses that I thought would be able to help me come closer to my final goal: a job as an automation engineer. Most of recent graduates I knew didn’t take any courses outside of the college, or if they did they were only limited to one or two training courses. I took eight different courses in PLC programming, Wincc and monitoring systems, Profibus, Ethernet, etc and that made me very unique compared to others with the same college degree. Having these training courses in my resume showed employers immediately that I was different from the other recent graduates and if they hired me, they’d be able to avoid training me from scratch. They knew that they hire someone who has been trained with the exact skill to work as an automation engineer.

This is also what I see now sitting on the other side of the table as an employer. Most of the resumes that are sent to me either don’t have any relevant training courses or just one or two. If I see a resume that has seven or eight practical training courses, his/her chance of being hired is way more than the others. This shows that they know what to do right off the bat and it also indicates that they have been committed to their goal of working as an automation engineer. They’ve invested time and money to achieve their goal and what employer doesn’t like a serious employee?!

2. Sell the heck out of yourself!

Top Directors of companies are always looking for someone who can add value to their company. In any circumstance, if they recognize someone who could potentially be effective for their company, they don’t hesitate to hire that person. But you need to show them how good you are. If they don’t know you then how can they be assured that you’d be a valuable addition to their team? It’s like having the best product in the world but not doing any marketing for it and then expecting others to come and buy from you. In this case, no one buys your great product simply because they’re not aware that such a thing exists! So you’ve got to have the ability and willingness to sell yourself in the best way possible and show and convince employers that you can add value to their company. If you don’t promote yourself, then who will?

One the best and most powerful tools that you can use to represent your skills is LinkedIn. Today most international and local companies jump into LinkedIn when they want to hire new employees. Research shows that professionals with a well-designed LinkedIn profile have more job opportunity than others. So if you’re a professional and don’t have a well-designed LinkedIn profile, then you’re missing on a good chunk of opportunities.

One the best books that I’ve read about how to use the power of LinkedIn to reach your professional career goals is LinkedIn Riches by John Nemo. If you’re really serious about your professional life, then I highly recommend this book.

3. You must be willing to pay the price.

When I was looking for a job, I searched for opportunities online and offline every single day. I sent my resume to every single good company that was hiring. Some of the companies were not based in the city that I lived in and sometimes I had to take a bus for a six or seven hour long trip (because I couldn’t afford to buy a plane ticket). The scenario was pretty much like this, the company secretary called to tell me that they liked my resume and to ask if I could interview the following day. I always said “I’ll be there!” and then usually took the bus the night before and arrived in the morning for a brief fifteen minute or less interview. If you really want to find a job, you need to have the courage to do whatever it takes to make that happen. Some folks don’t even take the time to fill out an online form for a new job opportunity. Then they wonder why they can’t find a job! Their excuse is “I’m so busy with my current job or with other things in my life. I can’t find time to look for new opportunities.”  My answer is “No, you’re not busy. There is always time to do what you want but the question is what’s the most important?”

4. Offer something that’s hard to ignore.

I used to ask for advice in every interview. I usually asked “In your opinion, considering the skills on my resume what is the best strategy for me to find a job?” I learned a lot of valuable lessons by asking this question. For instance, in one interview I asked the CEO of the company this question and he said, “Offer something that’s hard to ignore, for example say that I can work for six months for free.” It didn’t make sense for me at the time but I said “What the heck, I’ve tried a lot of things so far, let’s try this one too.” When I got home the day after the interview I picked up the phone and called some of the companies that I knew I had a chance with and offered to work for them for free for six months. After a few days one of them called me back and boom, I was hired! Of course the manager of that company was a good guy and they started paying me after two months because they were satisfied with my work. You can think about this type of offer too. Don’t act like the majority of people. Get creative! I’m sure you can find something to offer that’s hard to ignore.

5. Don’t expect to sit behind a desk at the beginning.

One of the mistakes that most young engineers make is that they expect to sit behind a desk right away at their first job in a company as a designer and programmer because they have an engineering degree! But this actually not ideal. If you’ve been hired as a newbie and you’re asked to do handy work (like construction work) do not waste the opportunity. When I was hired for the first time as an automation engineer, I was working in the hardest working conditions for about eight months: from wiring electrical enclosures which were installed at 100 feet above the ground on the cranes to cabling in factory basements. Now that I look back, those days were some of my best learning experiences I’ve ever had and they expanded my view for designing and programming. Even now that I’m a senior engineer, I sometimes get those type of work days if there is a need. So when you’re asked to do this type of hard work, don’t be lazy. Think of it as a learning experience that will lead you to becoming a serious and professional elite automation engineer.

I could go on and on with additional tips, but I don’t want to overwhelm you. So many blog posts offer long lists of advice, but they’re hard to remember and apply to real life scenarios. My overall advice is that if you want to get into the automation world without any professional experience, you need to prove to employers that you will add value to their company. No one cares how good of a student you were. The only thing that matters is whether or not you can add real value. As soon as you convince them that you’re someone who can, then you’re hired!

Now it’s your turn! I’d love to hear about your successes or lessons learned throughout your interview experience. Please share it with us in the comments below!