To protect and serve” appears on countless police and public safety vehicles in the United States. Although taken for granted by many, it is a serious motto for those in law enforcement, fire protection, and security fields. This same motto could appear on industrial enclosures as well. Their function is also to protect and serve.
Most enclosures are purchased for in-plant applications.
Although protection varies with the item (workstations, PLCs, DCSs, instrumentation, HMIs), respondents listed the following attributes as necessary when specifying an enclosure (in descending order): dustproof, waterproof, wash-down resistance, A/C cooling capability, EMI/RFI shielding, office-level/non-hardened capabilities, explosion-proof, heating capability, and UV protection. Dustproof, waterproof, wash-down resistance, cooling, and EMI/RFI resistance were invariably tagged for typical in-plant uses. Non-hardened enclosures were most used in standard computer/workstation applications.
Applications were further broken down by enclosure environments/location. The majority found their way to the plant floor, which included sanitary/wash-down and hazardous/dusty environments. Less than half that amount were used in an office environment and a small number (less than 2%) ended up out-of-doors.
Respondents chose availability from stock and cost as the most important factors when selecting enclosure suppliers. Other criteria affecting choice includes ease of use, the ability to customize (for example, add cutouts, colors, rack, rack locations), modular design, and the availability of technical support. The only change in the listing from previous surveys (and eclipsing tech support for the first time) was an increased preference for modular enclosure design.
Leading applications for enclosure use, survey respondents, said, were SCADA (48%); machine control and CNC equipment (40%); and motion control and robotics (38%).
A modular enclosure system is designed to be flexible and easy to expand in capabilities or size. According to Troy Miesee, industrial business and product development manager at Rittal Corp., “With more and more companies providing to the global market, it has become important to be able to adapt a standard design, whether it be an enclosure or a complete system, to the application or requested need. These designs can easily have accessories such as shelves, brackets, and mounting panels added, as well as the ability to bay multiple enclosures together to increase the size of the system.”
Modularity allows designers and builders to configure and build various systems from a standard platform, which can reduce engineering and assembly time and enclosure inventory. Bill Geese, product manager for CCS-Inc. suggests another reasons for the rise in the popularity of modularity: “In most production-floor system rollouts, the enclosure is seen by the customer as the component with the least risk. For this reason, the selection of an enclosure system is not attended to until late in the project, when the requirements are fully understood. By then the project schedule does not allow for customization in the traditional sense, so customers turn to enclosure lines that support customization through modularity,” he says.
The survey says the greatest percentage of enclosures are specified in carbon steel or stainless steel. These materials shared the lead in earlier surveys. Most recently, aluminum enclosures took over third place from fiberglass/engineered plastic for the first time.
Lighten up with aluminum
Any number of applications require the rigidity, strength, and fire-resistance of steel enclosures. Although stainless steel can provide the corrosion protection that carbon steel cannot, both are heavy and may be ill-suited to an application when larger size, mobility, or ease of installation are required. Aluminum offers lightweight construction (similar to both fiberglass and engineered plastics), with many of the benefits of steel.
Compared to two years ago, respondents to this survey showed increased use of stainless steel and aluminum.
The high cost of stainless steel and fiberglass/ plastics has also made aluminum more attractive. Rittal’s Miesse says his company has seen an increase in requests for aluminum. “However, Rittal sees this only as a next best alternative to stainless and fiberglass when price is a major issue,” he adds.
CCS-Inc.’s Geese adds that the rising cost of petroleum products present in most, if not all, non-metallic solutions may also be partly to blame. “Couple this with the fact that it is very difficult and costly to do true customization in non-metallic solutions, and one can easily accept that aluminum has become more popular than non-metallic enclosures,” he adds.
For enclosures used indoors, this survey asked about respondents’ familiarity with RoHS (Restriction of Hazardous Substances) requirements affecting enclosures and consoles. Most (>90%) said they were not very familiar or not familiar at all with them. According to Ron Rotondo, product manager for Hoffman, RoHS relates to enclosure construction materials, specifically to corrosion-resistant plating (hexavalent chromium, for instance) and nonmetallic materials (some compounds in fiberglass materials). RoHS regulations restrict the use of some substances in manufacturing to try to prevent hazardouns material from leaching into the environment.
When properly disposed of, RoHS-compliant enclosures have limited environmental impact. The legislative environment around RoHS is changing. The European Union RoHS Directive took effect July 1, 2006. China and California are both considering similar directives. Users’ knowledge varies with business environments. Machine builders that export to Europe have already been impacted. Additional legislation will force everyone to become familiar with such regulations. Rotondo points outs that Hoffman’s online catalog marks compliant products with a RoHS emblem. “Currently, we are 92% compliant for all products. Additionally, customers will be able to request and download RoHS compliance certificates to build their technical file through our Website in early 2007,” he adds.
Users may take enclosure capabilities for granted because most products have met changing market needs seamlessly, living up to the motto: protect and serve .
Protection from contaminants
Slope-top workstation enclosures
Double deep fiberglass enclosures
Operator interface enclosures
Enclosure heat exchangers
Enclosures for PC boards
Other recently introduced products, from companies not named in survey results, include the following.
Reinforced polyester enclosures
Ultraline enclosures from Allied Moulded Products include industry exclusive mounting options, company says.
New Ultraline NEMA 4X electrical or electronic, fiberglass reinforced polyester enclosures from Allied Moulded Products comes standard with what are said to be industry exclusive mounting options, including an out-of-the-box mounting flange or adjustable mounting feet to cover various configurations. Ultraline also features molded latch keepers, a tongue-and-groove seal design, and a flange design. A clear polycarbonate cover option is available for instrumentation applications where critical electronic equipment must be visible and protected from the elements.
Allied Moulded Products Inc.
NEMA-rated enclosed workstations
TecStation Xtreme is part of CCS’ line of NEMA-rated enclosed workstations. It allows companies to safely put computers in hazardous manufacturing and production environments where flammable gases and vapors are present. Stainless steel enclosure meets NEMA 4/4X requirements and is suitable for Class I, Div. I and II locations. Product uses instrument quality compressed air or inert gas in its purge system to maintain a slightly higher internal pressure and prevent flammable gases from entering the enclosure. Pressure is regulated, 60-115 psi, and it can function at 4-131 °F. Other features include self-sealing doors with lift-off hinges, a monitor viewing window, and keyed compression latches. Enclosure accommodates desktop LCDs (up to 21-in.) and small form factor PCs in pedestal or benchtop models.
Transport, cool electronics safely
Air conditioned transit cases from EIC Solutions Inc. are designed to safely transport, protect, and cool electronics. A built-in thermoelectric air conditioner provides the cooling needed to maintain safe temperatures within the cases for instruments, computers, telecommunications equipment, terminals, surveillance devices, and other specialty electronics in the harshest environments. The design combines a thermoelectric air conditioner with a durable, stackable, lightweight, portable transit case, suitable for use in various industrial, military, and defense applications. The impact- and corrosion-resistant cases are available in various sizes, colors, and types, including 19-in. rack-mount styles, clamshell designs, and custom configurations. Built-in 200, 400, 800, or 1500 BTU thermoelectric air conditioners are available in NEMA 12 or 4X configurations for indoor or outdoor use. Optional equipment available for the cases includes cable exit ports, locking latches, casters, shelves, insulation, RF/EMI protection, desiccant material, and custom colors.
EIC Solutions Inc.
Enclosures Direct (EDI) says it has 3,000 standard enclosures in its wall mountable line.
Enclosure services beyond standard items
Product and service options from UL- and CSA-approved manufacturer Enclosures Direct (EDI) include standard NEMA electrical and electronic enclosures in stainless steel or powder coated mild steel powder said to compete with the industry’s larger, global enclosure manufacturers. Product flexibility and unique service options include more sizes to choose from (3,000 standard enclosures in its wall mountable line), no minimum order size, quick turnaround (days rather than weeks) on modifications, and better pricing. EDI enclosures are manufactured on a just-in-time basis using robotic welding and metal finishing. Options include foam-in-place gaskets, a patented hinge for improved waterproofing, powder coated finishes, and small or large order modifications (hole punching, special weld studs, paint colors). All secondary operations are all done in-house.
30.5 mm pushbutton enclosures
Allen-Bradley 800H pushbutton yellow plastic enclosures from Rockwell Automation increase visibility for 30.5 mm pushbuttons.
Global OEMs and manufacturers who require increased visibility of push button stations for e-stop applications will like the new yellow Allen-Bradley 800H pushbutton plastic enclosures from Rockwell Automation. The yellow 30.5 mm pushbutton plastic enclosures add to a line of definite-purpose style enclosures. The bright color is designed for applications requiring e-stop with a yellow background or applications requiring increased visibility of the push button station. The UL and CSA rated enclosures are lightweight and high-impact resistant. Increased flexibility is available with 1-4 hole configurations, and cover-to-base orientation makes it convenient for customers to correctly select and install.
To protect and serve” appears on countless police and public safety vehicles in the United States. Although taken for granted by many, it is a serious motto for those in law enforcement, fire protection, and security fields. This same motto could appear on industrial enclosures as well. Their function is also to protect and serve. It is a job taken very seriously by enclosure manufacturers: providing users with a way to protect electrical and control components from a variety of problems, including environmental contaminants, moisture, temperature changes, shock/physical damage, and tampering. Enclosures also serve as a terminus and/or mounting site for electronic or control devices and their wiring.
The right protection
According to a recent on-line survey by Reed Research Group and Control Engineering magazine, enclosures are widely applied. The majority (51%) are used for in-plant requirements , with 30% used for OEM (resale) requirements. The remaining 19% were bought for both in-plant and OEM uses.
Primary applications vary widely (see accompanying graphic). Responses put supervisory control and data acquisition (SCADA) applications at the top of the list, followed closely by machine control/CNC and motion control/robotics applications, which are common (almost generic) in discrete manufacturing operations. Continuous and combined continuous/batch processes also account for a large share of the applications, coming in fourth and seventh in the list of uses. Compared to a year earlier in 2005, most applications remained in essentially the same or close to the same order.
Dick Johnson is a consulting editor with Control Engineering. He can be reached at firstname.lastname@example.org .