Control Panel Design for Beginners Pt.1: Specifications & BOM

What's up Automation Nation! Today we're going to be diving into the basics of industrial control cabinet design and electrical schematic generation. This is an absolute cornerstone skill of industrial controls and automation engineering and since this is a huge and complex area, I'm going to attempt to chunk this series into fairly logical chapters and subsections. Today's video is going to attempt to explain how to do all of the pre-planning from taking a general problem statement or process diagram or just overall automation goal and how to turn that into a set of documents that become the foundation for your control panel design. From these I.O. lists, controls narratives, and P&IDs, we can then spec out the control cabinet hardware that's necessary for our build. From individual component specification, our PLC, HMI, and I.O. card requirements, all the way to using the environment that you're installing the control cabinet in to inform picking out the correct cabinet that's specifically rated for those conditions. In the next videos, we'll then dive into the actual control cabinet layout creation in electrical schematic software. We'll define terminal block locations, power distribution, overall cabinet hardware design, and then dive into specific I.O. and networking diagram examples. And then finally, we'll finish this series with constructing the control cabinet together and I'll talk through some of the do's and do nots of best practices of building an industrial control cabinet as we actually do it together. To ground this whole series in a practical project, I'm going to treat this series as if we're actually designing a real world example of a home brewing system, which is a great example of a practical place you might see automation and also something most hobbyists and makers would find enjoyable. If you don't like beer, hopefully you at least like automation. This video is sponsored by Cofasso, who makes a terrific engineering CAD software suite, and more about them later in the video. And be sure to leave a like on this video, subscribe to the channel so you don't miss the rest of the series as it comes out, and now without any further ado, let's get into today's video. Now this might sound obvious, but the first step in creating a new control cabinet design, and pretty much all of engineering, is clearly defining your project requirements. If you're creating a general I-O enclosure that's going to support an enormous portion of a chemical or oil and gas facility, you might want to design some big four foot by four foot giant cabinet with room for multiple racks of I-O expansion cards, and plan for analog inputs, digital inputs, digital outputs, analog outputs, maybe even ethernet devices, RTDs, I-O link, and other advanced sensors, if you're really trying to create a general solution that'll meet your needs for I-O all over a factory and support expansion. But on the flip side, if you're looking to build a small standalone tool and you have a very clear picture of what inputs and outputs you're looking to tie to this control panel, you might be looking for much smaller cabinets and just enough I-O cards to support that project, with maybe a couple spares just in case. And the way to begin defining these requirements is typically with a set of P and I-Ds, or piping and instrumentation diagrams, for fluid systems. But for a mechanical motion system like belt driven conveyance or a pick and place gantry, you may need something like a motion block diagram or an overall system architecture design. If you have a really detailed mechanical model in a 3D CAD software, you could always mark that up and call out key I-O on that where you need to. The point is you need something showing the process or equipment that you're trying to add automation to, and call out the key I-O points on that. For our build, and to push this tutorial forward, let's check out what one of these P and I-Ds might look like on a classic home brewing setup called a heat exchange recirculating mash system, or HERMS for short. Now, we'll be looking at these P and I-Ds and talking about the system a lot in the coming videos, so we don't need a super deep dive into how this actually works. Rather, just a speed run should be sufficient for now. You fill up what's called the hot liquor tank with water, but liquor actually just means water. It's old-timey brewery speak, I think. Then you heat that tank to a target temperature, transfer it over to the second vessel called the mash lauter tun, where it will steep on your selected grains and hops, basically making a beer tea known as wort. You refill that hot liquor tank with more water and keep that vessel heated to a target temperature that varies based on what kind of beer you're trying to make. Then you continuously recirculate your wort through a heating element inside the hot liquor tank for a set amount of time, again based on your recipe, and until you get your wort to the right temperature. Then you eventually transfer that wort to the boil kettle, where it boils off some organic compounds for taste and purity, and I don't know, some other stuff. I'm not actually a beer expert. And then you transfer it to a chiller plate to bring the temp down a bit, and into a fermenter vessel where it sits, sometimes for several weeks, and ferments, and here is where it actually becomes a tasty, ready-to-drink beer. I have intentionally gone sort of controls and instrumentation heavy on this P&ID, which is frankly not something you would always do for a home setup, but this is a controls and automation tutorial after all. So I've basically designed what a fully automated HERMS system would need. You can see this piping and instrumentation diagram shows both the fluid and process connections, but also it explicitly calls out where we would need to see control valves, pumps, heaters, and temperature sensors and flow meters. From this P&ID, we can highlight the controls points and now make what is known as an I.O. list, or input-output list. At its most basic form, this is a list of all the input and output sensors in the system, calling out what type of signal they'll be, so we know what to plan for our PLC and I.O. rack. Most commonly, you'll have digital inputs and digital outputs, where discrete or digital means true or false, one or zero, on-off, or open-close. That's digital inputs and outputs. Analog inputs and outputs have a varying range instead of simple on-off control. Inputs are things you would monitor about a system like pressure, temperature, or flow, and outputs are things you would control the environment with, like pumps, and valves, and motors. From this I.O. list, which often gets expanded to include tag names representative of how you would find this device in a PLC, wire labels, what type of I.O. card it should get landed on, and sometimes you use this I.O. list directly in the bill of materials creation, so you'll even call out rack slot channel of the I.O. But for now, let's take the simple I.O. list and focus on the total quantity of each type of signal, since that's ultimately the most important thing that factors into speccing out the right components for our control cabinet design. For a build like this, with about 35 total I.O. points, we can see exactly how many channels for each type of signal and sensor we need. And as I said before, you usually want to avoid using a hundred percent of your available signals, even if you feel pretty good about a design. So you'll want to consider a 10% margin on I.O. signals no matter what, in case of last minute expansion, extra sensor needs you might be forgetting, or creating an incomplete P.N.I.D. And when you finish doing the design steps outlined in this video, you'll have a thorough I.O. list, bill of materials, and P.N.I.D.s. From here, you'll need to create a drawing set using a computer-aided design software, like the one from today's sponsor, Cofasso. And you can tell while using it, Cofasso is an electrical CAD software developed by people who actually design panels. They know the pain points engineers and draftsmen face while doing so every day. You simply draw your schematics and Cofasso does the tedious part for you. It can auto-connect components, add live device numbering, cross-references that update themselves when you're done, and one-click bill of materials generation, terminal plans, cable, and wireless when you're done with your base packet. They also support major manufacturer macro libraries, DWG and DXF drawing file formats, and you can even create hydraulic and pneumatic schematics as well with their symbol libraries. And not only does Cofasso offer free licenses for students, technical schools, and universities if you email cofasso at cofasso.com, but they're also offering a six-month free trial to all Lamaster Tech subscribers when you email them or contact them through their website contact page and mention discount code lamastertech6. The link to check out Cofasso is in the description of this video, so go check them out and thank you Cofasso for sponsoring today's video. Now, before I actually throw any part numbers at you for this design, let's discuss choosing your main PLC brand. There are frankly dozens of very competitive vendors capable of making PLCs, I-O modules, terminal blocks, sensors, drives, cabinets, HMIs, switches, power supplies, and everything else you need to put into a cabinet enclosure, and I cannot effectively cover all of them in this series, so I am going to generalize a bit. The majority of the time, if you're building an automation cabinet for a customer, the customer will have a site preference already in use. In North America, it's very common that a customer might specifically request that you build your full cabinet using Rockwell's Allen-Bradley hardware as much as possible because they're native to North America. Sometimes they may even have a standard model of PLC they want you to build with, which makes some of the procurement process a little easier because they're trying to stock fewer critical spares or have less variation on site. Internationally, Siemens is the largest and most common supplier in the world. There's tons of Schneider Electric in power and building monitor systems, Bekoff is in high-speed precision motion control all over, Omron and Mitsubishi are very popular in some Asian markets and some automotive markets, and AutomationDirect typically dominates hobby and slightly smaller scale applications and some of the most cost-sensitive customers because they're affordable and easy for everyday people to go procure. I'm sorry if this series is not getting done with your favorite hardware line, but understand if I say we need an 8-channel digital input card and then I spec out a Siemens card, you can almost certainly just type in 8-channel digital input card, Allen-Bradley, Bekoff, AutomationDirect, Mitsubishi, just use the description of the general component that I call out and add your preferred manufacturer at the end and you'll find the right part numbers for you. So with that being said, I am going to design this line with Siemens hardware, as I've been using a ton of it professionally and I already have a personal license for their programming software, TIA Portal for Lemaster Tech. As we go item by item that we'll need for this enclosure, I'll add it to another working document known as a Bill of Materials or a BOM for short, B-O-M. Now for a small cabinet build like this, I know I'm not going to need a ton of super complex code or even get close to the limitations of Siemens' more economical S7-1200 PLC line, so I'll make a 24-volt DC option which will