Interlock switches foil false activation

"Some machines use standard limit switches for safety interlocks, but they could be falsely actuated, either accidentally or deliberately, posing a danger to the machine operator," says Ron Cunningham, Cutler-Hammer product manager. "E48 switches eliminate the possibility of false actuation through the use of a key system." The switches lock machine guards in place and automatically shut a machine when the guard is removed. The switches have three forms of mechanical action to ensure they cannot be actuated. The standard switch interrupts machine operations when the key is removed. The latching model locks the actuating key in place until an internal solenoid is activated by a timer or stop-motion detector (a manual override key can disengage the actuating key when power to the machine is off). The E48 line allows the company to be a single-source, industrial switch supplier. Cutler-Hammer: Product Code 4738

Hockey Puck relays go ceramic

The latest version of the Hockey Puck relay features a ceramic substrate for direct contact with a heat-sink surface instead of the usual metal base plate--reducing thermal resistance between the solid-state relay's power semiconductor and the external sink. Thermal efficiency, and device longevity and reliability are thus improved. The Hockey Puck combines PowerTherm(R) circuitry or Fused Copper(TM) mounted power semiconductors with ceramic surface-mount technology in the control and opto-isolation stages of the relay. For relays up to 55A, PowerTherm has the lead frame (containing the power devices) applied directly to the substrate to use the ceramic's heat dissipation. Above 55A, the company's Fused Copper technology molecularly bonds copper to the substrate to manage the internal power semiconductors. Teledyne Relays: Product Code 4739

Sealed switches simplify integration

L-Series rocker switches are easy to integrate--fitting standard mounting holes with wire leads, 0.250 tab solder lugs, or PC terminals--with no retooling necessary. Triple seals qualify the switches to IP67; a roller pin mechanism obviates lubricants, allowing -40 to 85C operation; and welded lamp connections and internal, jumper-less terminals resist shock and vibration. "It's a neater, cleaner package all around," notes Carlingswitch's Jerry Peplau, switch product manager, "especially the one-piece, solderless internal-jumper terminals that eliminate the need for external jumpering." Twelve terminals permit extensive switch and lamp circuit options, including LED and incandescent illumination, or laser-etched rockers. Carlingswitch Inc.: Product Code 4737

Current-interrupt in a compact package

By using a monolithic chip design, Solid State Optronics (SSO) engineers developed the M211, which, the company claims, is the world's first solid-state relay (SSR) with a current-interrupt in a miniature 4-pin SOP package. The device uses a GaAs infrared LED optically coupled to an integrated driver/output circuit. The MOSFET-based output permits ac/dc switching of up to 400V and 120 mA. The current-interrupt protects downstream circuitry from current spikes. Division Manager Juan Kadah notes, "The M211 is SSO's response to the mantra 'smaller, better, cheaper.' It is a stepping stone, allowing SSO to offer higher function integration in smaller packages." Applications include mobile telecommunications, laptop computers, and medical electronics. Solid State Optronics: Product Code 4740

Terminating the terminator card

PCI Hot-Plugging and GTL termination bus switches are 5V devices that enable peripherals to be installed while a web/network/Internet system is running, without any server downtime in such multiprocessor environments. The switches also ensure data integrity using patented input undershoot circuitry, that prevents false switch enabling during isolation. Thus false data is kept off the bus. The GTL termination bus types are used in Intel Pentium II and III^TM environments that use Slot 1 and 2^TM for CPU cards, and provide an alternative to using a separate terminator card for the unused slot. According to Kay Annamalai, Pericom product manager, "It is important to keep the bus functioning during any peripheral insertion or removal. Device buses, such as in servers, all need termination for the empty slots and the only solution offered until now was the termination card." Pericom Semiconductor Corp: Product Code 4741

Programmable switches image data

IS Series switches of software-controlled pushbuttons are programmable to "allow real-time data, from text to moving images, to be displayed on a panel-top switching matrix," says Ray Lange, NKK Switches product sales specialist. When grouped together, the switches can display sequential information. Switch superstructure facilitates both vertical and horizontal mounting. Backlit red/green illumination and 36 x 24-pixel resolution permit reading under low light. Lange adds that by featuring data presentation, and not just on/off indication, the switches can reduce panel size by up to 75% in applications such as music lighting and sound systems. Other uses include communication systems, medical equipment, and air traffic control panels. NKK Switches: Product Code 4742