Innovative wiring methods for the electrical cabinet of the future

With prototypes of a new generation of PUSH In terminals Weidmüller has already presented one idea on achieving automatic mounting-rail assembly in time for the Hanover Trade Fair in 2009.

A fully automatic pick-and-place robot selected, identified and fitted components onto a DIN mounting rail; the robot received the positioning information from the Weidmüller software RailDesigner® – which includes an interface to the higher-level CAE system. Now Weidmüller is taking the next logical step and is examining the topic of wiring.

New electrical cabinet architecture

"Today, electrical cabinets are home to components with different designs, types of connections and angles of connection. As long as there is no widely accepted standardisation new developments in this field can only achieve limited improvements" says René Meier, manager at Weidmüller Switzerland. "Achieving a permanent increase in efficiency in electrical cabinet construction requires a completely new and uniform structure. If we were to standardise all components and connection types without exception we would be able to achieve a significant increase in efficiency. That in turn would mean savings in time and costs for the user."

With the old architecture going into the depth of the electrical cabinet (z-axis) with a robot can hardly be realised.

Together with the Swiss electrical cabinet manufacturer and automation specialist Althaus Weidmüller developed the following idea:

Implementing control circuits and the entire wiring for cross-sections up to approx. 4 mm² in the form of a mounting plate on the rear of the electrical cabinet:

• Modification of the electrical cabinet in that there is no DIN mounting rail frame and no assembly of control and switching devices onto the mounting rails

• Prefabrication of cut-outs produced in the rear mounting plate by means of CNC processes

• Direct integration of practically all electrical control, switching and connection elements in these cut-outs

Fully automatic wiring by a robot

To implement a concept of this nature it is necessary to make appropriate adaptations to the design of the electrical cabinet components to be mounted. "We see PUSH In connection technology as a basis for the electrical cabinet of the future, because it stands for intuitive and fast connectivity, high levels of safety as well as flexible application options", explains René Meier. "Components with PUSH In contacts that are always in a constant and clear-cut position can do more than substantially simplify manual and semi-automatic wiring processes. They would even make possible fully automatic wiring by a robot."

A robot is able to reach high and wide positions. However, it is very difficult to access depths inside an electrical cabinet with a robot arm. The cut-outs in the mounting plate provide unhindered access to the connections as these are located on the rear of the components and eliminate the depth dimension. Robot positioning is simply required to be oriented on an x-y coordinate system.