PLC Chiller Control Series – PLC TYPES – Process Chiller Pro Podcast

PLC Series – Types of Chiller Control PLC’s – Process Chiller Pro Podcast

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PLC Series – Types of Chiller Control PLC’s – Process Chiller Pro Podcast.

Let’s face it, walking into a process chiller controlled by a Programmable Logic Controller or PLC, or just about any other PLC controlled mechanical equipment you run into in the field with a PLC can cause some initial anxiety, right?

Especially if you are walking up on a machine that you are unfamiliar with.

What should you do when you have ruled out all of the obvious mechanical issues and everything points to the PLC as the source of the problem?

And if you are thinking, well, I will just call the equipment manufacture, we all know that can add hours that you don’t have onto your service call.

When your customer is down, the last thing they want to see you do is to sit on hold on their dime.

This episode is part of a series I am doing on PLCs that will help you avoid feeling overwhelmed when faced with needing to get a PLC-controlled machine up and running that you are not familiar with.

Let’s take a few minutes today to take the first step to determine what type of PLC you are working on.

This is the first step in your PLC troubleshooting process that we will take on in this episode of the process chiller pro podcast. 

Episode(s) That Support This Topic.

Episode Transcript

What I’m going to do now is address the elephant in the room when it comes to programmable logic controllers. PLCs, when you get called out on these things, and let’s say you have a process chiller, or you have some other type of mechanical equipment, you go through all your normal mojo of checking out the refrigeration system, the electrical systems, you’re looking for stuff that’s burned, pitted, that kind of thing, after you go through that whole process, you find out that wow, okay, there’s something really going on here with this PLC. Now that whole situation makes a lot of people really uptight. And it’s understandable because A, the manufacturers out there are making changes to their PLC designs and form factors. And they’re changing these things all the time. So you literally could have one type of PLC on a piece of equipment and the very next year have something totally different. So it’s almost not impossible, unless you’re like you work for manufacturer. If you’re a mechanical contractor, or technician that works on all different types of equipment. It’s just tough. It’s a very anxiety laden situation, when you’re pulled in to look at a machine and you’ve done all your stuff and you find out alright, there’s something going on with this PLC, this series that I’m doing is designed to at least get you jumpstarted. Because the last thing that your customer wants to see you do is jump on the phone with the manufacturer and be standing there on their dime waiting for somebody to pick up the phone and help you troubleshoot this thing. So I’m going to show you some steps in a series of videos here. And this is the first installment today that you can follow to at least give you an idea on what the heck’s going on. It’s not that you’re not going to eventually have to talk to the manufacturer matter of fact, most likely you will, at some point, you just want to be able to have enough information to talk to that manufacturer and hopefully come to the solution faster than you normally would before you watch this series. So this is the first installment as I said in this particular episode, I’m talking about the types of PLCs out there. And I’m breaking this down as simple as I possibly can. There’s two basic types of PLCs. And we’re going to identify what those are in this episode. The benefit of knowing the two different types out there is going to be super important at the tail end of your diagnostic process, which I’m going to show you in this series, when you’re having that all important conversation with your customer or your boss about what needs to be done on this particular piece of equipment. Before we get started, I wanted to just do a quick safety announcement. The content that process chiller pro podcast provides is really designed for experienced technicians only. So if any of the tasks that I describe in any one of my videos are making you feel uncomfortable, unsafe, you’re not comfortable and know how to be safe with electricity, refrigeration plumbing, I suggest that you stop and find somebody with more experience to supervise you or help you do some of the tasks that I’m describing. I want you to be safe out there. So please don’t take any chances that can get you hurt. Hey guys, I have an exciting announcement, we just recently made some updates to our three most popular online courses at process Tiller If you’re a technician that’s looking to improve your skills a little bit, maybe get some specialized training to be of more value to your customers and your employer. Or if you are an employer, a contractor that is looking to augment your existing in house training with online training that can be accessible from any device. This is a really great opportunity. Just go to process chiller Academy comm just scroll down on the homepage, and you will see the course area. If you go into the course page, you will see that we are currently for limited time. We have a promo code of chiller Pro that will save you 25% on any one of these courses. So I hope you check it out. And I’m looking forward to seeing you in class.

As I touched on in the lead into this episode, you went out to a customer site that has a process piece of equipment, whether that be a chiller or something that’s critical to their business, and it’s down and you’ve already went through all of your normal troubleshooting things. Usually most technicians will first fall into looking at electrical issues, contactors wiring, things like that, and then they move on to compressors and fans and pumps. And you just look for any obvious signs of failure. And after you do that, you’re going to in this scenario that I’m creating here, you haven’t found the problem. You’ve got a good indicator that the PLC assuming this is a PLC equipped piece of equipment, and it’s not operating correctly or it’s it’s offline because of the PLC. So as I mentioned earlier, there’s a lot of anxiety about that. And the first step is to figure out what type of PLC that you’re looking at. And this will become really valuable to you, as you go through your diagnostic process, I’m going to show you some diagnostic techniques that you would perform on the to different types of PLCs. But most importantly, the recommendations that you make to your customer based on the type of PLC you’re dealing with, is quite different, because there’s different ways different perspectives to go after it. Depending on the type of PLC that you’ve got, we’re going to discuss that in this episode. Now, most PLCs will operate essentially the same, and we’re going to have a dedicated episode or two on that process. But basically, what you have is you have inputs, you have a processor, where you have ladder logic of some type operating. And based on that logic and the data that’s coming in from the inputs, there’s going to be outputs. So those outputs are doing things like turning compressors, and fans and pumps and things on and off. So that’s in a very, very simplistic way. That’s what these things do. I mentioned earlier that there’s two different types of PLCs that you’ll find out in the market. The first is a modular type. And the other one is what I call integrated or board based, these are going to be the the essence of all the types of PLCs that you’re going to come across out in the market today. As a quick reminder, more so in this episode than in others, I wanted to remind you that we produce all of our podcast content in both audio only and video. So the things I’m going to be talking about in this episode, I’m going to try my very best to create word pictures. So you can kind of see in your mind’s eye what I’m talking about. But if you’re a little confused as some of the things and you hear me referencing things I’m putting up on my screen, make sure that you make yourself a note to check out this content on video, which you can go to process chiller Academy comm and check out what I’m showing on the screen, I think it’d be very helpful, because we have a lot of contractors out there especially that like to use our podcast as in house training when they get everybody together once a month or whatever. So just wanted to give you a quick reminder that so the first type of PLC I want to talk about is going to be a modular type. And a modular PLC is just kind of how it sounds. The major component of a modular PLC is your CPU. And that’s the device in what I call the control stack that contains the proprietary software. Generally, I say it’s proprietary because the company that manufactures the piece of mechanical equipment that has this PLC in it has done some customized things to make that machine operate the way they want it to. So the PLC will contain a CPU just like a CPU on a computer. The other things you’ll have snapped on to what we call the control stack is going to be inputs and output modules. And they’re just like they’re just like a means is you’ll have a module or several modules that stack on that will take inputs, temperatures, pressures, and you name it you basically your imagination is really only limitation is finding out you know what you can put on to a mechanical piece of equipment for input, the other type of modules is going to be output. So as I mentioned earlier, so the input module will take in data from the real world, feed it into the CPUs programming, and then once it figures out what it wants to do based on the operating conditions, it’s going to go ahead and tell the outputs to do certain things that could be turning on a fan turning on a pump, turning on a compressor, or sending a analog signal out to something like a variable frequency drive. So that’s essentially what a modular PLC is all about. Now, one of the benefits of a modular PLC is it’s modular. So if you have an input or an output card, for example, fail, then you have the ability to just unplug and snap that module out of there and put in a new one. That’s very helpful, especially if you get into a situation where you know you’ve got a system that’s down. Another benefit of a modular PLC that a lot of people don’t know about is the hardware that goes into modular PLC is typically not proprietary. In other words, there’s a company that manufactures that hardware. I’m showing I Dec here, this is one of many, and what they do is they sell that hardware to the equipment manufacturer, whether they’re making chillers or cooling towers or whatever is controlled by a PLC. They sell that hardware to these companies. And these companies do their own programming to develop their specific algorithms that take that input data, make a decision about what they want it to do, and then turn on outputs, right. So that’s one big benefit. And I’ll tell you, the secret that a lot of people don’t know is the proprietary things about a modular PLC is usually limited to the CPU. So all that’s work that houses all the custom programming, typically, but the modules, the input and the output modules, they typically do not. So where that turns into a huge benefit is if you happen to have a system that’s down, and you do your troubleshooting diagnostics, which I’m going to teach you in the series. And you make a determination that the problem is say an input module, maybe a thermistor is not the thermistor is working fine. But it’s not sending the correct data to the PLC, which is causing the PLC to malfunction, you can actually potentially go to another hardware supplier or the original OEM hardware supplier, and buy just that output module. And that’s a huge benefit. Because if the manufacturer that made the machine has a supply chain issue, or for whatever reason, they can’t get you the output or the input module that I’m talking about, you may be able to go to other sources, other supply chains to be able to find that part and there’s a good chance that you’ll be able to simply snap that on there, and the CPU will identify, oh, I know who you are, and go ahead and start working. So that’s something that it’s not really talked about too much. And there’s are exceptions to it. But that is one big benefit to having a modular PLC, you don’t typically have OEM, it’s not really OEM hardware, there’s, you know, you can buy the many distribution channels for that hardware. And you can buy modules that will typically snap on to an existing CPU. Now that all being said, you can tell I’m a fan of modular, if you haven’t picked that up already, there are some downsides. And the big downside is usually the hardware itself, the finish CPU, and the modules all put together and put into a machine, those are typically going to be more expensive, as compared to what we call an integrated PLC, which I’ll talk about in a minute. So there’s a little bit of a disincentive for manufacturers to use modular PLCs on their equipment, just because it makes their equipment more expensive. And that’s one downside to it. So in the chiller world, it’s hard to make an argument to put a modular PLC on a two time packaged chiller, because the percentage of what that PLC costs as compared to the percentage to produce the entire machine is a high percentage of the total equipment. So sometimes that just doesn’t work out. So manufacturers have to go to the integrated style board. Next up is what I call the integrated PLC and you’ve seen these you may not recognize what they are. But these are basically a PC board. That is pretty easy to identify, you’re gonna see a lot of parts mounted on a usually a green colored board. It’s all soldered on there. And it’s all put together nice and neat. These types of boards are typically less expensive as modulars, which I’ve talked about a minute ago. And they are very customized to the type of equipment that they’re operating on.

Are you a contractor or facilities manager, or maybe even an end user that has to use process chillers as part of your business. And maybe you’re having some short term issues like reliability or energy efficiency issues, or maybe longer term, you’re trying to put together a quality maintenance program that makes your machines run more reliably? Well process chiller Academy offers consulting services. And right now we offer a free 30 minute consultation. We’ll talk with one of our engineers, and we’ll help line you up with either short term or long term solutions. To make your equipment run more reliably and keep your processes running. All you have to do is go to the process chiller website and you’ll see on the homepage, there’s a link for consulting services. And right on that services page. You will also see how to schedule your FREE 30 minute consultation. So don’t wait check it out. And we’re looking forward to helping you as soon as we possibly can. Just like modular they will have the processor which is usually a chip mounted on the board. They’ll also have inputs and outputs and they you name it on the configuration they can be pretty much anything because they’re customized for the machine equipment that you’re working on. Now one nice thing about the integrated type control board is that a lot of times the wire connections are usually more accessible than with the modular style. So getting your probes in there to do diagnostics, which we’ll talk about in future episodes in this series is typically a little bit easier not in all cases, but typically a little easier. Now, the downside to an integrated board is that if you happen to have input or output fail, in other words you have or processor or some damage to the board itself, you got really two issues. One is you have a totally OEM setup. So that means that the board is can probably be a little bit more expensive. And the other challenge that you have is you’re subject to whatever supply chain challenges that particular manufacturer that has had that board design for their their equipment, you’re there, you’re at the mercy of their supply chain. And that’s a real tough situation. And I mentioned in the beginning of this episode, knowing the type of board you have versus you know, modular versus integrated, is a real substantial part of how you go about your conversation with your customer. So now that we’ve talked about how to identify the types of PLCs, that’s modular and integrated, that you’re going to see in in the field, we’re going to be talking about how to troubleshoot both of these types of POCs in the field in the next episodes. Now, the cool thing that I’m going to do is I’m going to actually create real life scenarios that I’ve lived myself on both these types of PLCs. And we’re going to go through sort of a little bit of methodical way of doing diagnostics on these. Now, what you’re going to find is there’s similarities on how to do troubleshooting on these two types of PLCs. And what I’m going to do is you’ll, you’ll be able to see the similarities, but then I’m going to show you some steps to take, they’re going to be very specific to these types, these two types. So stick around, we’ve got a lot of really great stuff coming up. As I mentioned, we’re going to be doing I don’t know, four, maybe more episodes on this subject, because out of all the subjects that I get requests to talk about PLCs is definitely up towards the top. Alright, so let’s do the mail. This question comes from a guy named Gil Tate. And he’s out of Palo Alto, California, the Bay Area. That’s where I’m originally from. So nice to hear from you, Gil. Gil wants to know, does any company you know have make universal PLCs to replace OEM PLCs? That is a great question. So Gil, the short answer is not that I’m aware of it, I’ll give you kind of a short story. situation that happened to me. When I first got into the manufacturing business.

There was just we had no PLCs. And come around 1999 2000, we decided to make a change to putting PLCs in our machines. And at the time, I was outsourcing all of my manufacturing to another company, I won’t name names, and they happen to own a PLC manufacturing company. Anyway, long story short, those PLCs turned out to be ultimately unreliable. There were certain circumstances that came up with the hardware or the software. I think we were at the tip of the spear as far as getting these types of PLCs out of machines, and they just didn’t work that well. So fortunately, my volume was quite high with this particular manufacturer. So I decided to go out and find my own modular style PLC. I mentioned that I was a fan of that. And we started manufacturing all of our brand chillers through this plant to their chagrin, they weren’t happy about it, but we did it. And we had amazing success, the failure rates went down significantly lower and to almost non existent. And that’s just the direction we went. So we still had about it was a couple 100 I believe machines on the market when we switched over to modular PLCs that they’re working in the field and they were intermittently failing. And we didn’t want to leave our customers high and dry. So we developed our own PLC retrofit for our chillers. Now over the years, we actually had companies buy the retrofit. And we were totally clear with them that this Retrofit is not for any other machines other than ours. And they were talented enough to be able to retrofit our retrofit on to other brand chillers. Now what I learned from that whole process the reason why I went down this whole storyline is that you need a very skilled technician who’s super comfortable with electrical understanding PLCs and can retrofit these things efficiently. It’s not for the faint of heart. And as I’ll talk about in future episodes, one of the things that you have to keep in mind whenever you retrofit your machines with anything, especially if it’s under warranty, in these cases, these machines were not, you’re going to void the warranty and doing that, but in some cases, you just don’t have a choice.

So bottom line on this question, Gil? Yes, it’s possible. I don’t know of any companies, because we don’t make the retrofits anymore. I don’t know of any companies that actually make universal retrofits. But if you do run across somebody, let me know because we do have people that contact me through process chiller Academy for consulting work, and they need help in that area. So if you run across something, definitely let me know. Next question came in from Mark Schneider a lot shorter answer. I’m sure. He’s not a Henderson, Nevada. And he wants to know, can I plug in to a manufacturers PLC and make changes to the programming? The short answer to that one mark is no. Most manufacturers, they will not give you access to their source code I know we never did, the only thing you’re going to get is you’ll have parameters. If your machine is equipped with a touchscreen or some type of an interface, they will allow you to make certain changes to the source code through a field variable. And I don’t want to get too complicated, but it’s pretty common to allow technicians to make changes to fan cycle pressure settings, high pressure, low pressure, freeze free stat type things, you’ll be able to make those types of changes because you have to. But as far as being able to jack into a PLC, whether it be a modular or integrated style, they’re not going to do that I would be shocked. I’ve never seen a company that would actually do that. So hopefully that is helpful to you. So in this week’s words, terms and quotes segment, I’m going to be talking about a very popular and super important component called a crankcase here, you’re gonna see that term referred to as a cc H on electrical diagrams, and I’ll just do a quick explanation how they work. I know a lot of you guys know how they work, but apprentices out there that are just getting into the trade may not know the benefit of a CCA or crankcase heater is it will apply a little bit of heat to the base of a compressor. And the benefit of that is it keeps refrigerant liquid refrigerant from commingling with the oil that should be hanging out at the base of that compressor with the crankcase heater it keeps the refrigerant and the oil separated. Now, if you don’t have a crankcase heater, or your crankcase heater has malfunctioned, that migration will happen, especially in cold ambient conditions. And when that compressor starts that commingling will cause the oil to instantly turn into phone, it just basically explodes into foam. And that oil which is mixed with the refrigerants gonna get pumped right out of the compressor, down the compressors hot, hot high pressure gas line. And what you will do is run your compressor low on oil for a period of time until that refrigerant in that oil makes it fat way back to the compressor crankcase. So that’s essentially what it’s all about. Now, crankcase heaters are a maintenance item. So those you guys that are doing maintenances if you see a crankcase heater on a compressor, you want to make sure you check it and it’s it should be always checked because they do fail and they do fail and your compressors pumping out its oil, you’re going to have situations where your compressors will fail or at the very least dramatically reduce the life expectancy of the compressor. So that is a cch or crankcase heater used on very many compressors that are in the field today. Well this episode of the process children Pro is a wrap as they say. Thanks so much for joining me today. I’m very much looking forward to developing relationship with you and seeing if I can help you in your career path as much as I possibly can. I’m looking forward to hearing from you on LinkedIn where I’m at most of the time I’m also on all the social networks. You can also send me emails at M King at process chiller. and I will see you next week for our next installment of the process. Chiller pro podcast. You have a great week and go get them out there. I’ll talk to you soon.