Cable extension sensors for transportation system

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Variohm's cable extension transducers and pressure sensors are enabling the safe and reliable positioning and control of ISO containers and swap bodies.

Cable extension sensors for transportation systemBOXmover GmbH, based near Linz in Austria, has developed an innovative technology for combined load/unload and transportation of ISO containers and swap bodies. As an integral part of the technology, uses cable extension transducers and pressure sensors from Variohm EuroSensor to maintain safe and reliable positioning and control. is well proven in use throughout Europe for three-axis truck, truck trailer, saddle carriage and even railway wagon transportation, saving time and cost while offering more flexibility than traditional crane/terminal-based transhipment methods. The system employs two synchronised hydraulic actuator units permanently integrated on the vehicle that safely lift and lower the container sideways.

Each actuator unit has two telescopic cylinders, arranged as a triangular closed force and moment-free structure capable of lifting and lowering swap bodies with 16tons and ISO containers with 32tons gross weight, within a comparatively small working footprint. Not only does enable reduced standing and waiting times, the autonomous transportation/load/unload system enables delivery or collection from almost any type of location without reliance on special loading units, cranes, forklifts or ramps. This complete independence from the normal infrastructure required for container shipping offers transportation management many advantages, and has set new standards for optimising standardised container transhipment.

Variohm EuroSensor began working with BOXmover GmbH through its German sales office in 2006, providing technical support and application assistance for the early development phase of and related products for the transportation industry.

As the exclusive distributor for Celesco Inc in both the UK and Germany, Variohm EuroSensor was able to facilitate a custom modified version of the USA cable extension transducer manufacturer's SR1 series 'string pot sensor', which provides a durable, cost-efficient and high-performance position feedback system for wet environments and outdoor applications. For the latest development, the SR1CN, the sensor has a modified extended stroke length – from 3.5 to 3.8m - and a non-standard mounting bracket. Significantly, the sensor features a CANopen DS 406 device profile output from its plastic-hybrid precision potentiometer for simplified integration with the actuator unit control system.

Proven track record

The SR1 series was originally designed for off-road construction equipment and has a proven track record for demanding applications where its -40 to +85degC operating temperature range and IP67 sealing are important features. The SR1CN is located on each hydraulic segment of the actuator unit, providing position feedback that the control system uses to determine the extended and contracted distances for the container during the load/unload operations. The choice of a cable extension sensor ('draw wire sensor') for this application exemplifies the advantages of the technology in terms of simplicity and cost, far outstripping enclosed-cylinder linear position measurement systems. also uses a Variohm EPT3100 pressure sensor with 400bar rating and 4-20mA output. This has also performed very reliably for the project. BOXmover GMbH Managing Director and creator of, Dipl-Ing Rudolf Hubauer explains: "Variohm EuroSensor continue to provide us with excellent service and support. The stringpot position and pressure sensors have proven extremely reliable in the field – in particular the stringpot provides a very cost-effective position measurement solution."

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