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Home Articles DN signal connectors - History

DN signal connectors - History

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DN Signal Connectors now in industrial quality

Enhanced signal plug connector with specialised pressure-contact technology for mass production

The manufacturer of a timer- and remote-controlled detonator system for controlled detonation of sea mines was looking for a signal plug connector that would have extremely reliable contacts and would be watertight. The plug connector would be destroyed along with the mine, so it would be needed in large quantities at an acceptable price. This gave Schaltbau the idea of developing a high-quality signal plug connector for large-scale use – and the DN family was born.

In the past, signal plug connectors of this kind were used mostly in military telecommunications to transmit audio signals. They have a robust pressure-contacting system, and even when unplugged are watertight and insensitive to electromagnetic interference. These connectors are therefore suitable for use in rugged conditions. However, their cost has always been an obstacle to industrial customers.

The objective was therefore to develop a signal plug connector that combined the pressure-contacting system with a tough plastic housing at an industrial-level price. Thanks to die-cast housing elements, two-component injection-moulded plastic parts and automated assembly, the DN series emerged – a handy pressure-contact plug connector for industrial applications.

Press – twist – locked

The DN family has a bayonet fastening. The movement that locks the bayonet connection enhances the self-cleaning of the contacts – essential for reliable transmission of very low currents and voltages under industrial conditions. A depression in the moving contact catches an abraded material or accumulation of dirt. The bayonet coupling used here dispenses with the usual bayonet ring. This usually requires a rotation of 120° to lock in place (as in the case of MIL-C-26482, for instance). Although the DN family has a rotation of only 20°, this ensures secure positioning of the contacts and effective self-cleaning. A further advantage of pressure contacts of this type is that they make it easy to fulfil the requirement of water tightness when unplugged.

The unvaryingly low volume resistance ensures permanent, high reliability of contact, even with low voltages and currents in a wide temperature range. All in all, this pressure contact system gives the plug connector a long lifetime and high resistance to shocks and vibration. Shielding similar to that used in military plug connectors is of interest for all applications in which external electromagnetic fields have to be attenuated. So Schaltbau developed a metal version in addition to the plastic version. The variable structure of the metal series also allows shield-attenuation and filter discs to be used to give protection from external EMC influences. The DN family is modular in structure. This results in great variability with regard to use and installation. The back of the plug, for example, is shaped so that either plug end housings with sealing grommets or thermoformed parts can be used, or the plug can be injection-moulded directly onto the cable. On the socket side, the contacts are in the form of solder cups to receive the AWG20-... 26 cores. There is a version with soldering pins for use directly on fixed and flexible circuit boards. 

Uses for DN plug connectors. The DN plug connector comes into its own wherever field-bus data have to be transmitted reliably under rugged conditions, for example – such as in indoor or outdoor applications in extremes of temperature, for processes in dusty or damp conditions, for underwater applications, for use in heavily vibrating machines, in metal processing with cryogenic liquids and for transmission of signals under the influence of strong electromagnetic interference. Potential application areas are:

·          Mechanical and apparatus engineering: Control technology and process automation, machine-tool building, foodstuff technology

·          Traffic technology: Signalling equipment, rail and road traffic control equipment

·          Medical technology: Functional diagnostics (stationary and mobile equipment), analysis technology

·          Measuring equipment – stationary or mobile: Measurement of environmental data, deep-sea measurements

·          Audio and video equipment: Control units and systems in stationary and mobile units, monitoring equipment

·          Telecommunications: Radio equipment, communications systems

·          Mining and utility vehicles: Rail vehicles, agricultural machines



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