Your power supply has something to say: Smart power supplies share their health status

Many pieces of the control system require dc power in order to operate. A power supply failure for a critical process controller or device can lead to an unplanned shutdown of critical plant equipment or processes. Without critical event visibility, plants don't have the necessary tools to troubleshoot issues before they become catastrophic. Fortunately, there are solutions to these problems. Now, there are power supplies that can give you a window into their health. In this episode, Mike Bacidore is joined by Jay Hendrix, product marketing manager of Connected Power at SolaHD Emerson, to discuss the capabilities of smart power supplies.

Transcript

Mike Bacidore: Hello, and welcome to today's episode of Control Intelligence. I'm Mike Bacidore, editor-in-chief of Control Design and your host for today's podcast. In this episode, I'm joined by Jay Hendrix, who is product marketing manager of Connected Power at SolaHD Emerson. We'll be talking about power supplies and equipment troubleshooting.

Many pieces of the control system require dc power in order to operate. This could include sensors, motors, solenoids, valves, PLCs, controllers, HMIs, remote IO racks, industrial PCs, vision systems and network gateways. However, after the dc power system is designed and devices are purchased and placed in the enclosure, they're often forgotten. Maybe they're given a token look every now and then to make sure the LEDs are blinking, but as long as the system is functioning, all is good. But what happens if there's a failure with the 24-volt power system? A power supply failure for a critical process controller or device can lead to an unplanned shutdown of critical plant equipment or processes. Without critical event visibility, plants don't have the necessary tools to troubleshoot issues before they become catastrophic.

Fortunately, there are solutions to these problems. Now, there are power supplies that can give you a window into their health. Jay Hendrix is product marketing manager, Connected Power for SolaHD Emerson. He's responsible for product vision, strategy, and development for SolaHD-connected products. He has more than 30 years of industry experience in product management, building controls, and technical integration. Hendrix holds a bachelor's degree in electrical engineering technology from Purdue University and a master of business administration from DePaul University.

Welcome, Jay.

Jay Hendrix: Hey, it's great to be with you today, Mike. Thanks for having me.

Mike: Yeah, you bet. Great to have you here. So, let's jump right into it. What specifically are the benefits to monitoring 24-volt dc power supplies?

Jay: Well, we get asked that question a lot actually, Mike. People tend to buy their power supplies and put them in a cabinet, and they seem to last forever. And that's a good thing, but connectivity actually provides you a window into your power supply's health, and that gives you the ability to monitor where you couldn't in the past. And through this connection, diagnostic information is communicated on the network to the control system. This allows the operators to monitor and trend key information from the power supply, alerting them when critical events are occurring, and this enables you to catch the problems, hopefully, before they occur, because once things happen and things go haywire, it's too late at that point. And some of the information we might actually trend or monitor could be like over-temperature, or over-voltage, or too high a load. So, those are the things we want to try to monitor in advance where we couldn't in the past.

Mike: This phenomenal new age of smart devices has really given us kind of a window into what's actually going on and enabling everyone to foresee what could be happening rather than waiting for a failure event and then scrambling to make a correction, correct?

Jay: Exactly, exactly. Because we want to try to catch an issue before it actually happens.

Mike: Absolutely. So, what about a power supply that has a DCOK contact? Isn't that good enough?

Jay: Well, you know, that has its use, and that's been used for many years and still used today, and it's still going to be used going forward. That DCOK contact actually provides you an indication that the DC power output is still good, and that relay would open up if there's no DC power. That's very useful in redundant applications or in a safety shutdown sequence, for example. But once that opens up and the DC power is lost, it's too late at that point to do anything about it, you've already lost the DC power. So, it's really an after-the-fact indication.

Mike: Right, right. So, I know you touched on this already, but can you go into a little more detail about why it's important to monitor that 24-volt DC power supply? What can a smart power supply, like, what kind of information can it tell me?

Jay: Yeah, that's a good question. It's very important for those clients and customers and integrators where critical production process or batch production is absolutely important, and if that production process were to be interrupted or shut down, there would be catastrophic loss. Once you have that catastrophic loss, that whole batch is wasted. So, that means the equipment is offline during that time. That means they might have to dispose of the wasted batch, which could cost lots of money, and it could actually cause a safety issue.

So, what we wan to try to do is enable the operators and service technicians to catch a problem way in advance. For example, something that might be useful is to look for unbalanced loads because, in batch production, they use redundant power supplies because it's really important that they keep it running. But they might want to look at unbalanced loads or have additional loads been added in my power supplies over time because things happen in a plant and things are added. So, they never know when that may happen and after-the-fact is too late. So, a connected power supply can provide you real-time information such as the input and output voltage, current power supply temperature, power supply alarms and events, and even useful life information. And some manufacturers even make available temperature sensors built into their devices that enable them to show the temperature inside of the cabinet. So, this is all useful information that could be provided to the technicians and operators.

Mike: Well, yeah. I mean, that is kind of amazing. There's a lot of those things that most people, even 10 years ago didn't even realize that was information that could be useful, and now it's readily available.

Jay: Exactly.

Mike: You did mention the ability for some of these smart power supplies to be able to talk about remaining useful life. Can you talk a little bit about the life of a power supply? What factors would impact, say, the life of a power supply or the remaining life?

Jay: Yeah. So, really the life of a power supply is going to be affected by how hard it's been used. So, how hard it's been loaded over time and its environmental temperature, the temperature it's been operating in. So, we might call that stress, how hard the power supply has been stressed, and you never know, depending on the situation and the client, how that actually might change based on its usage within that environment. So, the things that really drive a power supply's life is stress, which is load and temperature.

Mike: Right. So, in terms of that overall useful life, I know at the beginning you mentioned that people think, like, you put it in and it lasts forever, but how long should a typical power supply last?

Jay: Yeah, yeah. A power supply should last at least 10 years. But again, depending on how hard it's used and stressed throughout its life, that timeframe's going to vary, it could be lesser, it could be more. But the nice thing about that is manufacturers are providing ways of knowing or giving you a better indication of what is the life left in a power supply, and that could be done by providing you the run-time hours. You can monitor the run-time hours from the power supply and compare that to the specification data. So, you know, "Hey, I've been running at 50,000 hours or 100,000 hours." Well, my power supply is rated at 200,000 hours at a certain temperature, this means I have so many hours left. So, I have to start thinking about replacing this power supply.

But even better than hours is some manufacturers are building in useful life calculations. So, this would be a calculation based on stress, again. We talked about stress earlier, but stress on the power supply. So, how hard it's been volted, and what's the environmental temperature that it's been operating in, and this calculation would give you a countdown indication. And that may be similar to, like, the oil change gauge in your vehicle or in your car. So, maybe you change your oil every 5,000 miles, right? And it gives you a countdown starting at 5,000 miles down, so a 100% down to 0%. So, the stress level indication or useful-life indication inside of the power supply may be similar to like that oil change gauge in your car, which would very useful information, right?

Mike: Right. Absolutely. Yeah, absolutely. So, the ability for the power supply to tell us things, great innovation. Can you tell us a little bit about the, say, the network protocols? So, for smart power supplies, what protocols are necessary, or what's available?

Jay: Right. The good thing about this is there's a lot of options here. It really depends on specifications of the project and what the needs are of the customer. You know, how are they communicating today and what protocols are they using on the project? But from an Ethernet standpoint, there's high speed, there's some good options here, Ethernet IP, EtherCAT, PROFINET, and even Modbus, or the TCP would be great options to provide communication from your power supply onto a network. In the process world, another heavily used protocol is HART, Highway Addressable Remote Transducer protocol, and that's used like in process control situations and that may be a great option, because you could leverage something that you're already using.

Mike: Absolutely.

Jay: And some suppliers have even adopted or used IO-Link, which is a short distance point-to-point protocol. So that may be an option for your situation.

Mike: Sure. Sounds like you have pretty much all the bases covered with those protocols.

Jay: Certainly.

Mike: All right. Yeah. Well, thanks. Great conversation. Very insightful, and to be honest with you, I had no idea power supplies were quite as smart as they are these days. It really moved into the Internet of Things world just like all the other devices.

Jay: Exactly. And I think our challenge is to get engineers and integrators and customers thinking about this sort of option on their project. So, as they're replacing systems that they think about using a communicating power supply, as opposed to what they've done in the past.

Mike: Absolutely. Great idea.

Well, thanks to all of our listeners for joining us today on Control Intelligence: A Podcast from Control Design Magazine," and thanks, of course, to SolaHD Emerson's Jay Hendrix for his insights into power supplies.

Thanks, Jay.

Jay: Thank you, Mike. And it's great to be with you today.

Mike: If you've enjoyed this episode of Control Intelligence, don't miss our older episodes and subscribe to find new podcasts in the future. You can find our podcast library at controldesign.com, or you can download all episodes via Apple Podcasts or Google Play.

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