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It is not only its remarkable vehicleconcept that has attracted atten-tion since the Smart came onto themarket. At 80 Smart centres inEurope, the three versions of the“micro compact car” – or mcc –have been presented to customersin a spectacular fashion. Just as in-novative as the vehicles themselvesare the fully automatic parking sys-tems, developed specially for themcc, the glass Smart Towers. Theyprovide space for 27-35 Smart carson several levels. And it is Beckhofffield bus couplers and bus terminalsthat convey the sensor signals forthe presence and position of vehi-cles via CAN to the supervising PCcontroller to ensure problem-free,fully automatic positioning opera-tion.

Parking by touch screen operationThe same maxim applies to boththe vehicle and to the parking sys-tem: visually attractive appearance,

simple operation and functionallysecure operation. For this reasonthe Smart Tower, developed byNußbaum Automobile Parking Sys-tems (Nußbaum Autoparksysteme)and Hayek Engineering, is based onan entirely new concept, one whichis breaking new ground for ware-house and parking system technol-ogy. On each of the seven floors –eight or nine floors are available asa special version – are four parkingplaces with dimensions of 4.3 me-tres long and 1.9 metres wide. Theground floor is an exception, whereonly three parking bays are availa-ble; the fourth must be dedicatedto the vehicle hand-over and pick-up bay. The parking places are fedby means of a lifting cylinder eleva-tor system with hydraulic telescope.This “shuttle” is the central liftingand functional element. It functionsas the parking platform in thehand-over station, and combines

Electronic bus terminals in automobile parking systems

Field bus power in Smart TowerOtto Nußbaum GmbH & Co. KG, of Kehl-Bodersweier, manufacture high quality lifting equipment, are

exploiting the electronic bus terminals from Beckhoff, of Verl, in their latest car parking system for the

Smart. The Nußbaum engineers are using the bus-independent terminals to implement efficient, CAN-based

control solutions for the Smart Tower. The value to the customer: The hydraulic transport procedure takes

only 2.5 minutes from searching to driving out.

the turning and telescoping func-tions required for placement andremoval of the vehicles at the cor-rect floors and bays. The Smart’sdriver places his vehicle on the shut-tle. Once green signal lamps indi-cate that the vehicle is correctly po-sitioned, he gets out and starts theautomatic parking procedure withthe aid of a touch screen that, forreasons of safety, is mounted out-side the tower. By touching the“IN” box the current occupancy onthe park is graphically displayed.A desired park level can also beselected. The screen displays thecurrent occupancy of the bays, andinvites the desired free parking bayto be touched on the screen. Thevehicle is transported to this park-ing location in the Smart Tower,and pushed into the parking baythere. Vehicles are removed accord-ing to the corresponding sequence,but in reverse.

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The emphasis is on safetyand space-saving

Altogether 27 vehicles can be bothstored and presented behind glass,using a minimum of space, in thisway. The average duration of aparking or removal procedure isonly about 2.5 minutes. Inductivesensors and photocells provideextensive checks on presence andmonitoring of position. Their sig-nals are conveyed via CAN to thecontrol computer by the electronicfield bus terminals, to provide thenecessary control information.

All the procedures that takeplace in the Smart Tower are con-trolled by an Industrial PC with Pen-tium processor and CAN bus inter-face card. The control technologyincludes not only the sensors, initia-tors, photocells and operating pan-el, but also the control software. Itregulates the individual proceduresfor placement and removal. The IPCindividually controls all the move-ments in the equipment. In practicethis means that all the set positionsare supplied to the axis controllersof the lift and of the telescope, andthat the PC then waits for their exe-cution. The shuttle’s axis controlleris connected through one of thetwo serial interfaces.

The lift’s controllers then con-vert the set positions into regulated

Each of the four parking bays onthe levels in the Smart Tower isangled at 90° to the next. For thisreason, the correctness of thetelescope position and the targetedparking bay must be determinedbefore starting a parking orremoval operation.

The Smart vehicles are storedbehind a full glass facade onthe small ground area of only67.24 m2. Its attractive designmakes the Smart Tower into twothings at once: an intelligentstorage system and an effectivepresentation area for sales.

quantities for the hydraulic valves,thus causing the hydraulic cylindersto move. The data is exchangedwith the peripheral components viathe electronic field bus terminalsover the CAN bus.

This underlines the advantageof the twin-channel field bus termi-nals from Beckhoff over 4, 8 or even16 channel versions available on themarket. Too inflexible and bulky,said the Nußbaum engineers. It isprecisely the small size of the indi-vidual items that reduces space re-quirements in the switching cabi-net. This is mounted in the centralentrance area, and for architecturalreasons needs to be kept as small aspossible. The allocation, moreover,of one terminal per sensor bringsprices down and reduces the liabili-ty to faults.

The configuration of the busterminals is also easy. In a purelydigital application, as is the SmartTower, the pre-set standard termi-nals do not have to be specially con-figured, but are simply chained as aterminal block. In this way a varietyof sensor products form an inte-grated system family. The followingmovements in the Smart Tower areregistered by sensors:– Real-time registration of the

position of the 4 lift cylinderswith the Nußbaum axis

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with its high level of user-friendli-ness, gives a real boost to the widerspread of automatic parking sys-tems in general.

The terminal rangeWith more than 80 different fieldbus terminals, Beckhoff now offerthe maximum available modularityof digital or analogue inputs andoutputs. The great advantage ofthese two channel and four channelfield bus components is the scalable– and economical – configuration ofa tailor-made field bus station. Thefield signals reach the higher-levelautomation equipment throughthe bus coupler, which is now avail-able for Profibus, Interbus, CAN-open, DeviceNet, ControlNet,Lightbus, Ethernet TCP/IP etc..Other extensions open up USB ap-plications, while in the terminals,new varieties of resistance bridge(strain gauge), and analogue sig-nals with 16-bit resolution, com-plete the range on offer. All elec-tronic terminal blocks are, with awidth of 12 mm, mechanicallyequivalent to a double 6 mm termi-nal. The dimensions of 68 mm x100 mm mean that the externalform of the bus coupler fits themeasurements of the terminal boxwith technical perfection. An in-formative connection panel having

Four hydraulic lift cylinders in thefour main supports of the SmartTower move the shuttle vertically,i.e. upwards and downwards. Eachlift cylinder has a displacementsensor, which records the distancecovered by the piston rod by meansof an incremental transducer in thefrictional wheel, passing it throughthe field bus terminals to thecontrolling PC.

controller-ROTAMES distancemeasuring system,

– Detection of the shuttle loadstate,

– Supervision of the correcttelescope arm orientationtowards the target bays,

– Avoidance of collisionsbetween the shuttle telescopeand the parts of the building,

– Determination of the zero-position of the parkingplatform,

– Limit switch-off and controlof the turntable.

Integrated system familyThe bus terminals bring this solu-tion, like all the other 80 SmartTowers, the benefits of consistentperipherals, uniform hardware/software interfaces and a sharedprogramming environment. Whatis more, the Industrial PC does notjust record all the operating and er-ror messages. Remote maintenance,diagnostics and control can also beimplemented, using a telephonemodem connected through its COMports.

The Smart is blazing a newtrail for automobiles, one that willset standards for decades to come.The same applies to the Smart Tow-er, which, with its carefully plannedsensors and equipment control, and

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The terminal range

With more than 80 different field bus terminals, Beckhoff now offer the maximum avail-

able modularity of digital or analogue inputs and outputs. The great advantage of these

two-channel and four-channel field bus components is the scalable – and cost-effective

– configuration to a tailored terminal bus. The field signals reach the higher-level auto-

mation equipment through the bus couplers, which are available for Profibus, Interbus,

CANopen, DeviceNet, ControlNet, Lightbus, Ethernet TCP/IP etc.. Other extensions open

up USB applications, while in the terminals, new varieties of resistance bridge (strain

gauge), and analogue signals with 16-bit resolution complete the range on offer. All

electronic terminal blocks are, with a width of 12 mm, mechanically equivalent to a

double 6 mm terminal. The dimensions of 68 mm x 100 mm mean that the external form

of the bus coupler fits the measurements of the terminal box with technical perfection.

An informative connection panel having LEDs for status display, push-in contact labelling

and removable labelling areas ensures clarity in practice. The two-wire and three-wire

conductors, with an additional connection for a protective conductor, make it possible to

wire sensors and actuators directly.

The new BusBox products represent an extension to the familiar terminal blocks.

The compact, robust and economically priced modules, built to protection class IP 67,

are designed for direct fitting to machines, and widen the spectrum of application of the

familiar Beckhoff bus terminals. The small, new 170 mm x 30 mm BusBox modules are

only 27 mm high. The product range is proof against dirt and water. It can be used with

any mix of signals, and so can be ideally adapted to extremely varied requirements.

With more than 80 different fieldbus terminals, Beckhoff now offer amaximum available modularity ofdigital or analogue inputs andoutputs.

LEDs for status display, push-in con-tact labelling and removable label-ling areas ensures clarity in practice.The two-wire and three-wire con-ductors, with an additional connec-tion for a protective conductor,make it possible to wire sensors andactuators directly.

The new BusBox productsrepresent an extension to the famil-iar terminal blocks. The compact,robust and economically pricedmodules, built to protection classIP 67, are designed for direct fittingto machines, and widen the spec-trum of application of the familiarBeckhoff bus terminals. The small,new 170 mm x 30 mm BusBox mod-ules are only 27 mm high. The prod-uct range is proof against dirt andwater. It can be used with any mixof signals, and so can be ideallyadapted to extremely varied re-quirements.

The presentation towers fromNußbaum are now offered forother types of saloon car (theNußbaum CAR Tower). Beckhoffbus terminal technology is usedhere again.