PECM Issue 28 2017 | Page 64

maxGUARD: control voltage distribution made easy Providing control voltage supplies to field-mounted devices is a headache for every panel builder, especially when the overcurrent and short-circuit protection are also needed. Even in these days of fieldbus systems, most control panels still need to deliver control voltage supplies to numerous field-mounted devices. The usual solution is simply to provide a terminal bar within the control panel and, if this is well designed and implemented, using versatile modern terminals like those in Weidmüller’s Klippon® Connect range, this is a perfectly satisfactory approach. Things get more complicated, however, when overcurrent and short-circuit protection are needed, either on a circuit-by-circuit basis or for groups of circuits. Any number of protection devices are available on the market but often, these modules take up a lot of space and their use often involves time- consuming, additional wiring. Weidmüller’s new maxGUARD system, which has been developed specifically for use with 24 V DC control supplies, combines load monitoring and power distribution in the same device. In addition, Weidmüller has combined the functions of power distribution and circuit protection in remarkably compact devices – for loads of up to 6 A, for example, maxGUARD modules are just 6.1 mm wide. In typical control panels, 50% less space is needed to provide protected control voltage supplies for field devices using maxGUARD than would be needed with the usual combination of terminals and separate protection devices. Also, wiring between the terminals and the protection devices is no longer needed, which significantly reduces panel wiring time and costs. 64 PECM Issue 28 The maxGUARD range includes single- channel modules with tamperproof fixed overcurrent ratings from 1 A to 10 A, and types with user-adjustable overcurrent settings up to 12 A. Four- channel modules, with ratings up to 6 A per channel, are also available. maxGUARD load monitoring modules provide instant visual confirmation of status using a green/red LED indicator. The range also includes an optional alarm module that allows status information to be sent direct to a PLC or other control device. For applications where several circuits in the field need to be connected to the same protected supply channel, and to reduce wiring time to an absolute minimum, the maxGUARD system includes a comprehensive range of cross-connectors, complemented by terminal-only modules without integral protection. Also available in the range are power-feed modules to accommodate the connections between the control voltage power supply and the maxGUARD system. The maxGUARD system uses PUSH IN technology for connections, ensuring fast reliable wiring. The system has a maximum overall current rating of 40 A and can operate from -25 ºC to +55 ºC without derating. Power feed modules can accommodate cables up to 16 mm2, and the electronic load monitoring modules can accommodate cables up to 2.5 mm2. You can see more information at www.weidmuller.co.uk; alternatively you can call on 0845 094 2006.