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Elektro-Hermann, an automation specialist, has decided to use Moeller Electric’s Smartwire panel wiring system as the basis of a design for a compact control system for a waste sorting plant.

Elektro-Hermann made the decision after it was approached by Sutco Recyclingtechnik, a recycling and waste treatment specialist, to produce a small, cost-effective control system for a new waste sorting plant.

Automatic sorting plants can incorporate numerous conveyors, all of which have to be individually controlled.

This means that, in the control panel, a separate motor starter, comprising a contactor and motor protection relay, is needed for each conveyor.

The starters are typically connected to a programmable controller (PLC) that provides the overall control functions for the plant.

In the case of the control panels that were being designed for Sutko Recyclingtechnik for use in the waste sorting plant, which is to be operated by Tonsmeier Dienstleistung, Elektro-Hermann engineers decided that more that 300 starters would be needed.

With conventional techniques, these would require a large amount of panel wiring to connect them to the PLC.

However, it is time consuming to carry out this wiring and there is said to be a significant risk of errors, which can lead to extended testing and commissioning times.

In addition, the wiring takes up a lot of space within the control panel and, should modifications ever be needed, they are difficult and costly to accommodate.

The engineers at Elektro-Hermann decided that Moeller Electric Xstart starters, used in conjunction with the novel Smartwire panel wiring system, would provide them with an effective way of addressing these issues.

Rather like a Fieldbus system that is optimised for use within the control panel rather than outside it, Smartwire uses a bus-based communication system to connect the starters to the PLC.

This allows the connections to be daisy-chained from one starter to the next.

The system is claimed to be fast and easy to use as all of the connections are made with ready-terminated plug-in cables.

These are available in lengths ranging from 85mm to 2,000mm, accommodating all normal control-panel requirements and, as they are pre-terminated, the possibility of wiring errors is completely eliminated.

Another feature is that the Smartwire system uses standard contactors and motor protection relays from the Moeller Electric Xstart range.

Each contactor needs to be fitted with a Smartwire interface block that clips into place in the same way as an ordinary auxiliary contact.

Finally, the contactors and motor protection circuit breakers are assembled into complete starters using a tool-less connector system.

Connectors are available for standard unidirectional starters and for reversing and star-delta configurations.

Although many types of PLCs support direct connection with Smartwire systems, the engineers at Elektro-Hermann decided to, instead, use an indirect connection via Profibus-DP gateways, as Profibus-DP was being used on the plant for the field connections.

Configuration for the gateways is carried out in the PLC with a GSD file in the usual way, while the individual Smartwire modules are automatically assigned addresses by pressing a button on the gateway.

Helmut Helms, project manager at Elektro-Hermann, said: ‘We’ve saved a lot of wiring time for the control panel and, because the Smartwire cables take up so little room, we’ve been able to save space.’ Wilfried Enghardt, head of panel building at Elektro-Hermann, said: ‘In addition to the benefits we got from Smartwire itself, the modular mounting system of the Xstart starters also saved us a lot of time.

‘In addition, Smartwire’s ability to use standard components is also a big benefit in project-oriented panel building.’

Moeller Electric

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