Enclose and protect
End-users and OEMs enclose sensitive control equipment and instrumentation to protect against environmental hazards. Enclosures also make equipment safer and more convenient, suggests product research from Control Engineering/Reed Research Group. On Oct. 5, 2004, an e-mail survey was sent to Control Engineering subscribers to learn about the protection used around computers, programmable logic...
End-users and OEMs enclose sensitive control equipment and instrumentation to protect against environmental hazards. Enclosures also make equipment safer and more convenient, suggests product research from Control Engineering /Reed Research Group.
On Oct. 5, 2004, an e-mail survey was sent to Control Engineering subscribers to learn about the protection used around computers, programmable logic controllers, distributed control systems, instrumentation, networking, human-machine interfaces, and other automation devices. As of Oct. 15, 174 responses were received from those involved in evaluation, specification, recommendation, installation, and/or purchase of enclosures/consoles for in-plant or OEM (resale) requirements.
Habits of enclosure buyers
Among those who specify, recommend, or buy enclosures/consoles:
77% require PLCs to have dust-proof enclosures. Waterproof, explosion-proof, wash-down-resistant, and air conditioning/cooling protection are also required more for PLCs than any of the other items under evaluation. Heating and EMI/RFI shielding enclosures are most often needed for instrumentation. Office-level protection is most commonly required for computers or workstations.
Nearly three-quarters of enclosures are 'off-the-shelf.' The remaining are customized. Ratio is consistent with past buying patterns.
70% do so for in-plant requirements; 44% do so for OEM needs.
SCADA and machine control/CNC tie at 42% as the most popular applications for enclosures/consoles; 39% pump, fans, blowers; 34% continuous/batch processing; 31% materials handling equipment; 30% motion control robotics; and 26 diagnostics, testing, maintenance.
51% find availability of stock most important when selecting an enclosure/console supplier, followed by 49% for cost, and 40% ease of use; 32% ability to customize.
93% have purchased enclosures/consoles from distributors, while 43% bought directly from manufacturers. Over three-quarters bought from Hoffman in the past year; 60 was the average number of enclosures/consoles each respondent purchased in the past 12 months, an average of $32,398 per respondent. Survey results suggest purchases of enclosures/consoles will grow over the next 12 months, with 40% expecting to buy more; half, the same number.
12% buy enclosures/consoles via Internet.
Steel vs. composite materials
The broad range of survey responses demonstrate the many challenges engineers face when protecting control systems in a wide variety of applications and environments, according to Doug Franz, Hoffman market manager, automotive, material handling and machine tools. Franz, commenting on materials, says, 'Despite the increases in steel costs over the past several months, carbon steel and stainless steel continue to be the most common enclosure materials. While thermoplastic and fiberglass raw material costs have increased, the rate of increase has been much less than steel. These composite enclosures can be a cost-effective solution to steel enclosures in certain applications. Polycarbonate and fiberglass enclosures are lightweight, durable, and easy to modify for cable/wire entry.'
Despite many available part numbers, Franz says modifications continue. 'Whether it's punching holes in the enclosure or subpanel, painting the enclosure to customer specification, or factory installing accessories to eliminate steps in their process, we frequently provide value-added services and expect this portion of our business to continue to increase.'
It's no surprise that most factory automation requires protection, says Rave Jain, director of engineering, Bud Industries Inc., particularly against dust, which 'could create problems for moving components, such as switches and relays, and heat build-up problems for other components.' Most components, including PLCs, require dust-proof enclosures, Jain says. Most electrical enclosures used in a factory/business environment are rated NEMA 4/NEMA 12 for dust and water protection. DIN-rail boxes, inside the main enclosure, are very popular in factory automation and for PLCs, he says, including recent Bud Industries introductions of UL/NEMA rack-mounted, sealed die-cast aluminum, and plastic boxes.
Packaged solutions to integrate control equipment are common for many customers, according to Leon Kythas, market manager, enclosed drives and soft starters, Square D/Schneider Electric. 'It is more common today to see manufacturers offering standard pre-engineered configurations to address this need. Enclosures offer protection with flexibility in many ways, such as mounting location, environmental ratings (Type 1, 12, 3R), thermal management, NEC compliance and protection for operating personnel as the primary reasons for demand.' One example responding to the need for quick delivery and configurability is the new Telemecanique ATV58 Split-Box Kit, for new and retrofit installations, Kythas says.
For more information on enclosures, visit www.controleng.com and the Web sites of the manufacturers of the products below.
Type 1 free-standing
An expanded family of large, freestanding A38 and A38D Type 1 Enclosures includes three new platforms. A two-door general-purpose enclosure and a line of one- and two-door disconnect enclosures join a one-door model. The A38 provides an economical alternative for applications that don't require sealed enclosures. More expensive, sealed Type 12 enclosures fitted with fans and filter kits, effectively degrade to a Type 1 rating, Hoffman says. Features include sturdy Hoffman cabinet construction on an integral 10-gauge steel base, lifting tabs, durable three-point latch with padlock provision, flush doors that are reversible on non-disconnect models, and a choice of panel or rack-mount provisions to accommodate 19- or 23-in. rack equipment. Enclosures may be easily upgraded to Type 2 with the addition of gaskets. The enclosures can be used for applications as varied as power distribution, main control, variable frequency drives, custom motor control centers, marshalling cabinets, or lighting control. Standard sizes and enclosure modifications are available as well as custom sizes, factory-punched holes, cut outs, and many paint colors. www.hoffmanonline.com Hoffman
High-pressure, IP69k hose down protection
Premium Panel, KL Premium Line, and AE line extension meet the IP69K rating. This standard guarantees protection against the ingress of dust and against the harmful effects of high-pressure jet steam cleaning. Unlike a NEMA Type 4 or 4X test, IP69K protects against a high-pressure jet stream (1,160 to 1,450 psi), high-liquid temperature (176rochemical applications, where high-pressure washdowns are required and elevated water/solvent temperatures are typical. www.rittal.com Rittal Corp.
Hoods prevents fan-drawn moisture
Rain Hoods are designed for use with standard fan and filter kits to prevent rain, sleet, snow, dropping water, or other fluids from being drawn into the enclosure. They are made of 0.063-in. carbon steel and powder coated ANSI-61 gray. SS kits are made of Type 304 stainless with No. 4 brushed finish. Kits fit 4-, 6-, or 10-in. fan and filter cutout. www.saginawcontrol.com Saginaw Control & Engineering
N1J Series Panel Enclosure is designed for indoor housing of controls, instruments, and components not requiring oil-tight or dust-tight protection. It's formed and spot-welded from 16-gauge steel. Formed steel covers close with a slotted quarter-turn latch. The full-swing door uses butt hinges; holes in back permit wall mounting; a bonding stud is provided on the door and a grounding stud is provided on the box. Enclosure and cover are finished in ANSI/ASA 61 gray powder coating. Inner panel has a white powder coating. Additional inner panels are available. Ratings and standards include NEMA, UL-50, and CSA Type 1, as well as IEC 529, and IP30. www.hammfg.com Hammond Manufacturing
NEMA 4X-rated aluminum boxes with external brackets
AN Series of NEMA 4X-rated aluminum boxes have external mounting brackets that can be mounted on a wall or panel without having to remove the cover and expose internal components. A permanently fastened mounting bracket, 0.09-in. thick, accepts up to No. 10 mounting screws (not included). Boxes are priced, sold, and packaged in quantities of one, making them ideal for equipment designed in-house, prototypes, or small production runs. Applications include instrument cases, meter cases, junction boxes, marine, and any wet, dirty, or washdown applications. Finish is natural aluminum or smooth black powder coat. A gasketed cover is attached with screws. Sizes range from 1.95 x 1.77 x 1.12 in. to 8.75 x 5.75 x 3.25 in. Cover mounting holes are roll threaded and screws are captive and recessed. Most models have internal guide slots for mounting PCB assemblies vertically. The boxes provide EMC protection, are die-cast of ADX-10 alloy, have IP65 and NEMA 4X ratings, and UL listing. Boxes can be machined and modified to particular requirements. www.budind.com Bud Industries Inc.
NEMA 4/12 enclosure has window
N412WC Ultimate Series Enclosures are designed to house and protect electrical and electronic components from harsh, dirty environments. Streamlined styling, flush latching, and durable finish are said to complement any high-tech electronic equipment. Bodies and doors are fabricated from 14-gauge steel; seams are a continuous plasma weld. Tub opening is increased and hinges concealed. It has a Plexiglass viewing window; doors are interchangeable and removable. Grounding provisions are provided, and quarter-turn semi-flush oil tight latches hold door securely. Accessories and options are available. www.hubbell-wiegmann.com Hubbell Wiegmann
Split-box ac drive kit
An easy-to-assemble kit lowers the cost of providing coordinated motor control for variable torque fan and pump applications by making it easier to accommodate last-minute project changes. Square D Altivar 58 Split-Box Kit from Schneider Electric has two base enclosure sizes and includes a power circuit bypass box, wall-mountable back pan, standard pre-engineered options, and common controls. It is said to meet the needs of contractors and system integrators working on fast-track projects, allowing 21 configurations of NEMA Type 1 general purpose 1-25 hp motors at 460 V or 1-10 hp motors at 208/230 V. It complies with 2005 National Electric Code (ANSI/NFPA 70) Article 409 requirements that industrial control panels have a coordinated short-circuit current rating, as opposed to AIC ratings. The kit includes 3% ac line reactor, power isolation (cam) switch, and fully rated isolation and bypass contactors. All mounting hardware is included and all wiring and terminal blocks are connected for fast assembly. www.us.squared.com Schneider Electric
Clear polycarbonate cover
A clear polycarbonate cover is available in two new sizes, 8 x 8 in. and 12 x 12 in. for Stahlin J Series non-metallic enclosures. The covers provide full view of controls inside without opening the enclosure. All J Series products are molded from Stahlin's patent pending SolarGuard material, said to deliver the industry's best, independently proven protection from UV degradation. The company offers more than 300 configurations and 13 sizes of enclosures, from 6 x 4 in. to 20 x 16 in. with NEMA 4X, 12, and 6P ratings. www.stahlin.com Stahlin Non-Metallic Enclosures
IP65/NEMA4 metallic enclosures
Wall-mounted metallic enclosures have single or double doors in sizes from 12 x 8 x 6 in. through 48 x 40 x 12 (h x w x d). They are manufactured from sheet metal with a thickness of 0.06 in. and include a back plate, door rails, gland plate with sealing gasket, locking system, and other mounting accessories. Enclosures with glazed doors, stainless steel enclosures, junction boxes, freestanding consoles, PC cabinets/ pedestals, and modular free-standing cabinet enclosures are available. They are UL listed and CSA approved. www.gavazzionline.com Carlo Gavazzi
Mighty Mount is a heavy-duty arm for 'Light' Industrial LCD Mounting. It pivots on two axes and is sturdy cast aluminum. It offers quick and secure vertical positioning and is said to keep the display and keyboard level as they travel vertically. Keyboard tray includes a detachable mouse tray. itsenclosures.com ITSEnclosures
Enclosure application, mounting arm, related reading
Here’s more about a SCADA application for enclosures in a tough environment, a light industrial arm for mounting an LCD and keyboard, and related reading about enclosures.
SCADA/PLC enclosure applications increase
Protecting supervisory controls and data acquisition controls and PLCs from dust exposure is a growing application need, according to Jeff Seagle, general manager, Stahlin Non-Metallic Enclosures.
SCADA Source, an automation company in Farmington, NM, develops SCADA telemetry systems for rural water users as well as automation and communication parts and service to the oil and gas field industry. The company asked Stahlin Non-Metallic Enclosures for a cost-effective enclosure that could provide a high level of durability with resistance to corrosion, chemicals, UV-degradation and potential impact. Stahlin DiamondShield fiberglass enclosures housed an Omnex radio, battery, and antennas in one UL/NEMA 4X housing.
“This was possible,” Seagle says, “due to a patent-pending structural design unique to DiamondShield enclosures featuring, among other attributes, no penetrating hardware. This enables every cubic inch of interior volume to be easily available and completely protected. SCADA Source benefited from the ability to manage internal mounting panels in a variety of ways, including the option of positioning panels on the front covers of the enclosures. Interchangeable hardware including covers, hinges, locks, and windows also adds to the overall versatility.” Clear polycarbonate covers allow full viewing without exposing controls to dust.
Additional Online Product
Mighty Mount is a heavy-duty arm for “Light” Industrial LCD Mounting. It pivots on two axes and is sturdy cast aluminum. It offers quick and secure vertical positioning and is said to keep the display and keyboard level as they travel vertically. Keyboard tray includes a detachable mouse tray. itsenclosures.com
For a listing of enclosure manufacturers, see www.controleng.com/buyersguide . Additional information about enclosures at www.controleng.com includes:
Find the full research study for this February 2005 “Product Research” report at the Control Engineering Resource Center .