Terminal Blocks

Trends in Terminal BlocksIncreased use of IDC technologyIncreased functionalityOne-stop shoppingReduced panel spaceTerminal blocks evolved from simple input/output devices to the contemporary products we see today. Used originally in the automotive and telecommunication industries, these wire termination devices have become the building blocks for a wide range of industries.


Trends in Terminal Blocks


  • Increased use of IDC technology

  • Increased functionality

  • One-stop shopping

  • Reduced panel space


Terminal blocks evolved from simple input/output devices to the contemporary products we see today. Used originally in the automotive and telecommunication industries, these wire termination devices have become the building blocks for a wide range of industries.


Francis Leynaert, vice president and general manager for Entrelec (Irving, Tex.), says, 'The market is switching to alternate ideas. Customer requirements are getting more complicated. They want more functionality, more intelligence, and more than just simple switching to signal conditioners.'


Dean Norton, product manager for Wieland Inc. (Burgaw, N.C.), says, 'End-users are looking for better methods and features like space savings, integrated electronic components, built-in test points, increased safety (such as the use of UL94V0 plastic material), and custom marking tags.'


Control Engineering polled 1,500 readers, in part, to examine trends in the terminal block product industry. Two hundred eighty-six completed the questionnaire, for a 19% response rate. In all, 91% of respondents specify, recommend, and/or buy terminal blocks. Sixty-two percent specify, recommend, and/or buy terminal blocks for in-plant requirements; 16% do so for OEM (resale) requirements only; and 13% do it for both in-plant and OEM requirements.


The study sought to determine what termination methods are currently in use, and what methods are preferred; examine what communication networks are in use, and what networks are preferred; and to investigate important characteristics end-users look for when purchasing terminal blocks.



Traditional vs. new


When asked about current methods of terminations and preferred use, 31% use screwless-clamp terminal blocks, while only 15% prefer this type.


And, while other methods are available, the most popular remains screw-clamp blocks, for security purposes. Ninety-three percent of respondents currently use screw-clamp terminal blocks while 77% prefer this method. Prewired is the third most-used termination method, with 17% currently using this method, while only 3% prefer prewired blocks. Still a distant fourth, industry experts expect insulation displacement connection to gain popularity as more OEMs learn the technology. (See graphs.)


Larry Freeman, product manager for Phoenix Contact (Harrisburg, Pa.), says, 'While screw technology is still the leader, the biggest trend over the last year has been the use of IDC technology.'


Mr. Freeman adds, 'People would rather not be the first to use a new technology, so they are waiting to see, but IDC saves labor, has top entry so the end-user can see what's going on, and it provides better bridging systems. Because speed is the key to keep up with competition, the biggest jump in IDC technology is that it saves installation time by as much as 80% compared to using a manual screwdriver.'


Wieland's Mr. Norton agrees on end-users' slow but sure acceptance of IDC technology.


'IDC will continue to expand into new industries as the comfort level of this technology increases. This will mean an increase in demand for greater varieties of IDC technology DIN-rail-mount terminals,' says Mr. Norton.


Though slowly gaining acceptance, IDC may have a long way to go before its popularity reaches screw-type termination.


Alvin Stewart, industrial controls product manager, Automationdirect.com (Cumming, Ga.), disagrees about the possible wide-acceptance of IDC technology.


'Insulation Displacement Connection technology has been around for 30 years. While very popular in the telecom industry, the IDC wiring method hasn't been as accepted in the industrial arena. I think the industrial markets will continue to prefer conventional wire terminations,' says Mr. Stewart.


People may never agree on a particular termination method. However, when asked what are important characteristics desired when purchasing terminal blocks, 72% of respondents overwhelmingly answered availability. Ease of installation was the second most-desired characteristic at 52%. While cost (32%), specifications (21%), and wide variety of special blocks (21%) were the next leading characteristics respondents desired when purchasing terminal blocks.


Carl Hicks, product marketing manager for Weidmuller (Richmond, Va.), says, 'By far, the most important characteristic is the form-fit-function of a terminal. This simply means that the product has to physically meet a user's application parameters (size, electrical requirements, color, ease of use, etc.). In addition, the product must provide innovative functionality to help reduce installation and/or maintenance costs for the OEM and end-user.'



Communication methods


When the survey asked what communication network respondents use, or plan to use in the next 12 months, 4-20 m/A signal is used most at 64%. Gaining in popularity over the past year, Ethernet came in close second with 60% of respondents. Other protocols in use are DeviceNet (36%), Profibus (21%), ControlNet (18%), and HART (16%). (See graph.)


Jim Bachle, electrical products manager for Wago Corp. (Germantown, Wis.), says, 'For the last several years, we have seen more of the process shift to DIN-rail- mounted products. We consistently receive requests to incorporate intelligence into our more traditional products. The advent and growing acceptance of fieldbus protocols is creating a new emphasis on smart blocks.'


According to Jim Gibson, industry segment manager for Weidmuller, terminal blocks may have a reduced presence in the future as distributed control network architectures continue to find home in larger applications. However, the vast majority of applications will use terminal blocks well into the foreseeable future.


Mr. Gibson says, 'Terminal blocks will be looked to for the reduction of panel space and overall costs while providing increased functionality. Manufacturers positioned at the forefront of terminal block technology will be most successful as perception gives way to the realized advantages of innovation.'


Other trends include one-stop shopping, use of software to design own assemblies, and smaller panels.


Terminal block products


For more information on terminal block products, circle the following numbers, or visit www.controleng.com/freeinfo. For a wider listing of manufacturers, go to Control Engineering Buyer's Guide at www.controleng.com/buyersguide.


Mini-spring reduces size, not features

Harrisburg, Pa. -Phoenix Contact introduces a high-density, spring cage terminal block family, ST. The mini-spring design reduces overall size of the terminal blocks without relinquishing features. ST product has a flexible, dual-channel push-in jumper system, which can handle chain and skip bridging using 2, 3, 4, 5, 10 or 20 position jumpers. There is a wire entrance said to eliminate the need to use a larger terminal block when ferrules are used. ST block has large center marking for easy access, readability and end-marking that labels each termination point. www.phoenixcon.com


Phoenix Contact


Circle 374


Sloped-roof design saves space, easier handling

Richmond, Va.- Z Roof series was designed to meet requirements for higher mounting density and more room at the connection level in industrial wiring systems. A sloped-roof design is said to enable the length of a Z Roof terminal block to be reduced as much as 36% compared with a standard tension-clamp terminal block. Terminal blocks are designed with top connections, with wire insertion and spring operation occurring from above and parallel to each other. This allows cable ducts to be mounted close to a row of terminals. www.weidmuller.com


Weidmuller Inc.


Circle 375


Digital I/O modules provide expanded function

Irvine, Tex . -Entrelec's 'systron' remote I/O terminal blocks, featuring digital I/O expansion modules, now offer analog expansion modules. The plug-in, expansion modules mount into a separate terminal block base, which is available with either screw-clamp or spring-clamp terminations. The expansion modules, compatible with Interbus and Profibus protocols, allow up to eight analog inputs and four analog outputs. The analog expansion modules also offer a number of design features to facilitate operation and maintenance. www.entrelec.com


Entrelec Intl.


Circle 376


Additions to terminal block family

Cumming, Ga. -Automationdirect.com features additions to its line of terminal block products which include direct-mount terminal blocks, insulated ferrules and crimp terminals, nylon crimp terminals, butt connectors, ring terminals, and fork terminals. Direct-mount terminal blocks mount to any backplane without the use of DIN-rails. Ferrules come in either single or two-wire insulated or uninsulated models, and are made from electrolytically tin-plated copper with either standard or DIN, color polypropolyne insulation rate to 105 °C. Nylon crimp terminals, made from electrolytically tin-plated copper, also rate to 105 °C. Butt connectors, ring terminals, and fork terminals are offered in red, blue, yellow or clear. www.automationdirect.com




Circle 378


Add speed, efficiency, cut wiring costs

Germantown, Wis .-FIT Clamp Series 290, featuring Fast Insulation displacement Technology within a terminal block, is actuated by introducing a wire, inserting a screwdriver and sliding the clamp towards the wire. FIT Clamp terminal blocks are produced in two, three and four conductor versions. It is said that OEMs can take advantage of increased speed and efficiency when using the FIT clamp to do factory wiring. FIT clamp is suitable for use with PVC insulated conductors 16-22 AWG and is available in gray, blue, and green-yellow to designated ground. www.wago.com


Wago Corp.


Circle 377


Designs allow testing without disconnection

Burgaw, N.C. -Designed to allow circuit testing without disconnecting wires, Knife Edge Disconnect Series is the latest addition of the 'taris' family of terminal blocks. Featuring built-in test points with a lever disconnect switch, the terminal blocks employ Wieland's taris-IDC technology which reduces wiring time by as much as 60%. The taris family includes two types, the 5 mm WKC1/TKM35, designed for 24-18 AWG conductor; and the 6 mm WKC 2.5/TKM35, designed for 16-14 AWG conductors.. www.wielandinc.com




Circle 379


Reflow-compatible spring clamp

Peabody, Mass. -PCD introduces the first line of reflow-compatible, high-current spring-clamp terminal blocks for wire-to-board applications on 0.200 in. and 5.0 mm spacing. SCM series offers the end-user convenience of spring-clamp terminal blocks, providing easier and faster field installation by reducing screwdriver manipulation. To provide flexibility, SCM series is modular where stacking single-position modules allows local assembly of the desired number of positions or poles. SCM terminal blocks are available in two basic versions, integral-lever actuated or screwdriver actuated, offering the OEM designer a choice for the end-product's installation. www.pcdinc.com


PCD Inc.


Circle 382


Expanded line includes enhanced features

Flemington, N.J. -Altech's expanded line of terminal blocks includes spring clamp, distribution blocks, and ceramic Euroblocks. DIN-rail blocks feature screw- cage clamps for maximum wiring efficiency and reliability. Spring-clamp terminals feature a top entry wire hole to simplify installation and reduced space. Distribution blocks simplify systems by eliminating the need for individual internal and external jumper configurations. Compact and durable Euroblocks withstand extreme temperatures from -20 to 800 °C. Functions include feed-through, disconnect, high current, multi-level, ground, fuse and standard, and custom integrated electronics. www.altechcorp.com


Altech Corp.


Circle 383


Design for use with three-wire sensors

Carlisle, Pa . -Sensor Terminal Block, designed specifically for use with three-wire sensors, is said to reduce the labor needed to assemble DIN-rail blocks, such as proximity sensors, by as much as 50%. The lock connection system used in the three-level TLS block is a pre-assembled fork bridging system that allows the positive and negative connections to be made by sliding terminal blocks together then tightening two integrated screws. Color-coded insulating covers are available for dc power supply connections. Covers provide physical protection and safety from bused connections and an additional marking area to customize the DIN-rail assembly. www.asi-interconnect.com


Automation Systems Interconnect


Circle 384


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