By Mike Bacidore, managing editor
Choosing between an industrial component and an off-the-shelf, commercial substitute can be intimidating, if you haven’t done your homework. An unnecessarily rugged industrial component could translate to a sizable amount of money wasted on excessive precaution. On the other hand, an inappropriately implemented commercial component could mean destroyed equipment, lost production time or even injured employees.
Knowing how to make the right decision comes with experience, but how many engineers come ready-made with that type of veteran savvy?
Practical wisdom included. Just add water.
Typically commercial components are more readily available and less expensive than their industrial counterparts, but their reliability can be suspect, especially in harsh environments where conditions, such as temperature or vibration, can be extreme. And some applications are more suited to one type of component than the other. But no hard and fast rules exist, and exceptions always arise.
“Even though coal mines and plants are harsh environments, a lot of times we’ll use commercial components,” says Bruce Bancroft, consulting analyst at Consol Energy (consolenergy.com), an underground coal-mining company headquartered in Pittsburgh. Bancroft heads a group that oversees applied improvements in Consol Energy’s engineering and coal departments. “I’ve had nothing but hassles with industrial PCs. I’d rather buy a commercial PC and put it in an enclosure. Industrial PCs have never lived up to their expectations. It hasn’t been worth it for the cost.”
With 17 complexes in the United States, Consol Energy needs to ensure the data communications between its underground mines and the above-ground preparation plants are in working order.
“We have fiber backbones running throughout our mines, and then we usually come into a patch box and a switch,” explains Bancroft. “We use a lot of standard Cat 5 cable and fiberoptic cable through a relay. We use more commercial-related type connectors for fiber. Any cable in Pennsylvania has to be stamped for flame-retardant capabilities, and we do pay attention to that.”
Because of shorter commercial component lifespans, industrial components often are chosen for their durability and longer expected useful life. However, at some point those industrial components may need to be replaced and sometimes that same product is no longer available. Guarding against the quandary of obsolescence is a simple task if the right steps are taken.
“The most important thing to look at is the history of the company you’re dealing with,” explains Barry Garrison, marketing director at Sealevel Systems (sealevel.com), Liberty, S.C. “You have to look at the company level, not the product level, and how they handle their program. How risky are commercial substitutions in these instances? It comes back to the nature of the application and the environment. If you start factoring in how important the application is, then you’re running a big risk [with commercial components].”
Companies can guard against potential obsolescence by examining the products and the philosophy of the company with which they plan to do business.
“Knowledgeable designers guard against obsolescence by examining the track record of their candidate suppliers,” says Peter Wood, vice president of engineering and operations at GarrettCom (garrettcom.com) in Fremont, Calif. “Typically low-cost commercial components are not properly designed and tested for longevity in harsh industrial environments. Adequate design and testing cost more and account for the higher industrial component cost.”
The expected lifespan of the equipment is important too. In Orange County, Fla., like every other county in the U.S., waste and wastewater utilities are ongoing public necessities.
“Obsolescence is a big problem as we often look at 10-to-15-year installations before they are overhauled,” says Joe Roegner, SCADA technician for Orange County (orangecountyfl.net) in Orlando, Fla. “After only a few years we get equipment that can’t be repaired. Due to the fast advance of technology you have to consider that in five years what you have could be replaced with even better equipment.”
Sometimes, an industrial component will provide the user with a longer window of time for both product availability and the eventual replacement of legacy parts, suggests Greg Dixson, marketing manager, automation systems, at Phoenix Contact (phoenixcon.com) in Middletown, Pa. “Commercial products exist in and are developed for a market that typically cares about price first, with product durability and support as a much lesser concern. In the industrial market, price pressure often is tempered by a non-negotiable demand for product reliability. As a result, well-designed and ruggedized products, even if their cost of manufacture is not the absolute best in the market, will remain competitive, and therefore in market demand, for a longer period of time,” he explains.
Dixson also notes that the customers of most industrial component manufacturers simply will not tolerate a vendor quickly making a product obsolete that has been tested and designed into an application (Figure 1). “Such a practice results in a customer incurring the costs associated with approving and specifying a new product,” he says. “Since most industrial manufacturers have many different products to sell to a customer, they will often extend legacy support of an older generation product for a great deal of time in order to keep their larger customers happy.”
PC-based controls are used in the plastics industry to optimize injection-molding machines. Obsolete components can bring an application to a quick halt.
Even with industrial components, obsolescence still can occur, so Garrison suggests looking for companies with a track record of well-documented revisions. “Do they maintain proper records and show what has been done when they make a revision?” he asks. “There are some companies that don’t keep control of that. Simply making a phone call on the revision and requesting the documentation should be a simple process. Once you put together a system and it’s working like you want it to, if a component in that system fails, you want to make sure you get the exact same product. A revision on that product might interfere with the application you’re running. On the technical end, if there’s a revision of any significance, it can cause your application not to perform as before. If the features they’re using on that product aren’t mainstream features, then the risk is even higher because those same features might not be included on the revision.”
One advantage industrial components sometimes will have over commercial is the strict adherence to standards they must meet. While commercial components also are subject to regulations, industrial products often have rules of their own.
“In most cases industrial components are mandated by the environmental specifications that must be met by the product to be acceptable in specific applications,” explains GarrettCom’s Wood. “Today these specifications typically are approved internationally, through IEC for example, although there are some industry specific specifications such as NEMA TS2 for traffic controller applications and military COTS requirements,” he explains. “The specifications are designed to ensure that products used in harsh industrial environments will withstand the rigors of high and low temperatures, high humidity and moisture, shock, vibration and dirty environments. In addition to special product design techniques for these environments, a product must use industrial components tested and certified by the manufacturer with -40 to 85 °C ratings rather than the 0 to 70 °C ratings of commercial components.”
In addition to their ability to withstand wider operating temperatures, industrial components such as switches also often include protection against power supply surge, Ethernet port electrostatic discharge, shock and vibration, according to Paul Wacker, product manager—industrial communication, Advantech (advantech.com) in Cincinnati. And they typically are shielded for use in noisy environments where EMI and RFI can be problematic.
The lesser standards that commercial components must meet could have an impact on the total cost of ownership. “Agency certifications and approvals are big considerations,” Wacker says. “Most commercial products carry only the most basic electromagnetic compatibility (EMC) certifications. Many are not Underwriters Labs (UL) approved. How will this impact your plant or OEM equipment?”
Using industrial components in industrial applications can have financial advantages, explains Phoenix Contact’s Dixson. “Generally speaking, we would say it always is advisable to use an industrially rated product for industrial applications,” he says. “Although it is true that not all applications always require industrial shock, vibration, noise immunity and temperature ratings, it definitely is not possible to know in advance which applications will fail if such ratings are not provided. The premium paid for a true industrially rated product is much less than the costs of field-service visits, machine downtime, lost data or perhaps, most critically, a damaged reputation with your customer. Therefore, it always is advisable to use the right industrial product for an industrial application.”
Whether the component is commercial or industrial, testing it in a specific application sometimes can be the difference between a successful implementation and system-wide failure.
“We provide customers with evaluation units, so they physically can run those products through their paces before they install them permanently,” says Sealevel’s Garrison. “You do the homework as best you can, making sure the parameters are appropriate, but there’s no substitute for putting the product in that system and testing it to make sure it will work.”
In Orange County, ensuring a component’s appropriateness is important, but networks can’t be taken off-line. “Generally, we test a few of them in non-critical sites,” says Roegner.
Brian Tutor, product line manager at Lantronix (lantronix.com), Irvine, Calif., emphasizes that the component manufacturer should be doing testing of its own to eliminate the risk of any downtime due to component failure.
“You have to be very careful in selecting the company for your component,” explains Tutor. “Some companies test their components. If it’s not going to be in a harsh environment, it may be OK to use quality commercial components. How risky are commercial substitutions? The risks are if you have a failure. What’s the downtime risk? The real key is if you’re switching from one vendor to another, you should know the theoretical mean time between failure. Any company should be able to provide that to you. If it’s a commercial substitution in a harsh environment, you are definitely taking a risk.”
The importance of communication between the OEM and its customer is critical, says Tutor. “Even if you have industrial-rated components, that might not be enough. It’s really more about what the customer wants. You’ll find commercial in certain environments. There’s crossover.”
Industrial products must be designed to standards, explains GarrettCom’s Wood. “The standards are typically more stringent than for commercial eqiuipment,” he says. “While UL product safety is generally applied to commercial products, industrial equipment must also meet NEBS and ETSI standards for telecommunications and the IEC 61850 standard for electric substations.”
Application Dictates Environment
While knowledge of the customer is important, certain applications clearly mean harsher or more demanding environments. And often, the more rugged the environment is, the more important reliability is.
Component failure is not an option at Orange County’s Biosolids Dewatering Building and Loading Facility.
“It would be very embarrassing to have a water plant fail due to a low-quality component we bought based solely on price. We often install equipment in cabinets that are subject to high heat, condensation, corrosive gases, vibration and other harsh environments that most commercial equipment is not designed for. Electrical damage from lightning is a big problem in Florida. These factors limit our choices to industrial-quality equipment that can stand up to these requirements.”
Like many component suppliers, Lantronix works with OEMs serving a variety of industries. “We have several markets,” explains Tutor. “Industrial automation markets expect the high-spec components. In building automation, it’s going to be more of a mix. Some stuff might depend on the environment. In security, we don’t see nearly as much need for the industrial components. In medical, it really does not require industrial. A lot of our products go across many vertical markets.”
Sealevel’s Garrison says key questions are whether the component is being used in an important 24/7 application and the harshness of the environment. “If it’s mission-critical or in a harsh environment, you don’t want to go commercial because they’re not tested for those types of applications.”
Long life and reliability in harsh industrial environments can outweigh the initial low purchase cost, states GarrettCom’s Wood. “Electric utility substations cannot afford blackouts,” he explains. “Water treatment facilities must continuously operate. Traffic signal failures can cause chaos. Surveillance systems must operate to maintain security. Expensive industrial processes cannot be easily shut down and restarted. Failure of vehicle-borne systems can threaten life and limb. There are numerous critical applications that cannot be met reliably by products built with commercial components.”
In coal-mining applications, for example, the environment can be pretty harsh. “Our IT department just uses standard Cisco network switches and puts them in a NEMA 4 enclosure,” says Consol Energy’s Bancroft. “For control at our power centers and around our equipment, we’ll buy an industrial component, like an Allen-Bradley PLC. Around our mining faces, we use industrial components because of the environment and because of the strict safety standards. If we have a sensor that’s exposed to the elements, we’d buy an industrial one. We definitely look at how rugged the enclosure or the face plate is.”
Power to the Component, Right On
Available power is a simple consideration some users might take for granted, but it can be a dead-end factor in making the right choice.
“With the exception of 1U rackmount models, most commercial switches are powered by a wall-mount power adapter,” says Advantech’s Wacker. “Using this type of switch in an industrial application poses a number of problems, including the need for an available AC receptacle and potential power loss since these type of switches use loose-fitting barrel-type power plugs that are easily disconnected. To eliminate these problems, industrial switches are equipped with screw-clamp terminal blocks, which allow direct wire terminations to available DC power in a panel or enclosure. They are secured with screws, and can be unplugged for maintenance or service.”
Phoenix Contact’s Dixson reiterates this caution because of increased risk of failure. “We would discourage a practice of misapplying commercially rated products in industrial applications,” he says. “Remember, the rating of an industrial product is only one consideration in the selection process. For example, even if the lesser noise immunity, temperature, shock and vibration ratings of a commercial Ethernet switch were acceptable, the product would not be directly powered by 24 Vdc and would instead come with a non-industrial power connector and a transformer-style wall plug that would perhaps be cable-tied into a 120 V receptacle plug. This architecture now introduces several additional potential points of mechanical or electrical system failure outside of the switch itself.”
Available power input for industrial switches is generally 12 to 48 Vdc via a removable terminal block, allowing them to be powered by 24 Vdc within the panel or cabinet, explains Wacker. “Many of the latest generation models even include redundant power inputs, which ensure uninterrupted communications, even in the event of a power supply failure.”
Click here to read Obsolescence Happens. A case history on Weiler Engineering's automation component changes.