The most recent uses for circular DIN connectors might surprise the inventors: unmanned robotic vehicles, cell phone towers, and exterior-mount radar guns in police cars, among others.
By Raoul Benoit and Ed Gambacini
Circular DIN connectors, originally designed to meet the needs of a previous generation, continue to evolve. The markets and applications of this proven, versatile connector series would be inconceivable to those who originally designed them. Without question, these are not your father's circular DIN applications. Circular connectors are commonly finding new uses in emerging technologies such as Universal Mobile Telecommunications Service (UMTS) antennas, portable medical instrumentation, and harsh-environment vehicles. Circular DIN technology has been around for a long time, but its diversity and its ability to adapt to different applications still make it an attractive option in many instances.
Old standards, new uses
These connectors are often integrated into applications in traditional fields like building security or food processing. However, circular DIN connectors are also commonly used in highly innovative "outside the box" applications. For example, the Defense Advanced Research Projects Agency (DARPA), the research arm of the U.S. Department of Defense, sponsors a race called the Grand Challenge. The race challenges the private sector and academia to develop innovative, unmanned, robotic vehicles that could operate in battlefield conditions without risk to military personnel.
In the first Grand Challenge race in March 2004, DARPA designated a racecourse of more than 140 miles in the Mojave Desert. One competing team from Virginia Tech incorporated IP68-rated circular DIN connectors into the design of their vehicle, which they appropriately nicknamed "Cliff" to match the rugged terrain of the course (see Fig. 1).
 FIGURE 1. "Cliff," an unmanned, robotic off-road vehicle, used circular DIN connectors in a DARPA competition over rugged terrain. |
Because "Cliff" was an open-air vehicle, the electronic components used for signal transmission had to endure the harsh environmental conditions found in the Mojave. The desert conditions made it especially crucial that the connectors could provide ingress protection that would effectively seal out dust. The Virginia Tech team selected a fully shielded type of circular DIN connector made by Lumberg. The 360º metal shielding was an important part of the functioning capability of the connector because it would be working in close proximity to other electronic equipment.
While the dust-tight characteristic makes the IP68-rated circular DIN a logical choice for unique applications such as robotic vehicles that have to perform in the desert, it also makes the connector practical for more traditional venues. For example, in the food and beverage industry, processors are always preoccupied with meeting sanitation standards. Every quarter, they must be prepared for a visit from the local Health Board. The inspectors will check for a variety of things like holding temperatures of inventory as well as cooking temperatures; but one of their highest priorities is to observe cleanliness and cleaning practices. Acceptable sanitation in food processing environments involves alkaline bleach and consistent washing, which includes lots of splashdown. The IP68 watertight rating of the circular DIN connector makes it a viable candidate to operate in that kind of environment. Its watertight characteristic can ensure functionality even if working wet is one of the requirements (see Sidebar).
Emerging technologies
The 360° shielding plays a major role in UMTS radio tower connectors, where multiple antenna systems share a common structure. These circular DIN connectors are the latest evolutionary development of this extremely adaptable product series. Designed to facilitate remote communications between radio-tower base stations and the antennas mounted on top, these connectors are manufactured to AISG standards and IEC 60130-9 specifications. They come in standard eight-pole configurations and are rated IP67 watertight (see Fig. 2).
Benefits of the UMTS connectors include the ability to connect the antennas in serial daisy chains, the remote control of the antennas, and overall reduced wiring costs. It is estimated that more than 100,000 radio tower antennas in the U.S. are suitable for retrofitting with UMTS connectors, in addition to new towers under construction.
Other applications
Emergency service vehicles present another application for the adaptable circular DIN connector. The IP68 watertight protection and 360° shielding allow these connectors to perform beyond the applications for which they were originally intended. Police cars, fire trucks, ambulances, and marine rescue vehicles are packed with communications and detection devices, all of which can interfere with each other if not properly shielded from EMI.
Externally mounted radar guns on police cars are an excellent application example. Several years ago, when handheld radar guns were deemed a cancer risk to officers, an externally mounted device was developed. Because it would be exposed to the elements, it had to be watertight. Still in close proximity to the other communications equipment in the patrol car, it also had to be EMI shielded to protect it from interference from onboard two-way radios, cell phones, video, and computer equipment. The industrial-grade circular DIN provides a perfect, versatile application solution. Its nickel-plated metal shell provides an additional level of ruggedness (see Fig. 3).
Additional applications for circular DIN connectors are medical instrumentation, production machines, measurement and control devices, audio/visual, monitoring equipment, CNC machines, encoders/decoders, and portable equipment. Another fast growing application fit for the circular DIN connector is in-field traffic control and monitoring. Recently, cameras and antennas have become part of the standard equipment installed at new traffic lights.
The medical device market is also growing for circular DIN. With rising healthcare costs and a persistent nursing shortage, the trend is increasing for take-home and off-site medical diagnostic equipment. Blood-pressure-monitoring devices at your local pharmacy are the most visible examples, as are in-home blood sugar testers. Although quick-disconnect push/pull connectors remain the most widely used medical device connectors, their high cost is increasingly turning attention to the more cost-effective circular DIN in applications not requiring frequent mating and disconnect.
 FIGURE 4. Newly installed traffic lights showing two video cameras documenting traffic. Big Brother is watching. |
Since the 1950s, the circular DIN specification has been revised six times to reflect the evolving product series and market applications. Like the newspaper and radio, newer products have been introduced to compete with it. Radio did not kill the newspaper, and television did not kill the radio. Rather, both have adapted and flourished within ever changing markets. No matter how many "new fangled" connectors are designed and brought to market, ten years from now there will be a decade's worth of new circular DIN developments and applications to report on.
RAOUL BENOIT is public relations specialist and Ed Gambacini is distribution sales manager for electronic components at Lumberg, 14121 Justice Road, Midlothian, VA 23113. Tel: (804) 379-2010; email: rbenoit@lumbergusa.com.
Anatomy of the circular DIN
The 41525 standard for the circular DIN connector was first developed and published in the 50s by the Deutches Institut fur Norming e. V (DIN) organization, or German Institute for Standardization. The DIN organization revised the standard five times during the 60s and 70s. It was finally replaced in the 90s by the IEC.
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Most circular DIN connectors are standardized and share mating compatibility among manufacturers. A typical IP68 watertight circular DIN (above) has nickel-plated housing, threaded coupling, knurled grooves for hand tightening, and flats on the base for wrench tightening. The interior features gold-plated contacts, solder contacts (up to 12 poles), collets, and an O-ring for water sealing.
