Reliable current control for thousands of robots

Many industries rely on LÜTZE's current control system. Today, a car manufacturer is using the system to monitor the current control for robot applications in its car body shop.
This was basically started by Henry Ford more than 100 years ago when he invented the conveyor belt. Since then, there has been an on-going competition to boost productivity in the car manufacturing sector, each manufacturer optimizes and accelerates its processes, whilst also increasing the diversity and expansion of possible model variants at the same time. Robots have long since become an indispensable tool, from the car body production through to the final inspection, robots have been used to automate the large number of simple and repetitive work steps.

The company Jäger Elektrotechnik GmbH from Eppstein were commissioned to develop a matching control cabinet for the welding applications in car body shops, to completely control the welding tongs that are operated at the end of the robot arm. Several hundred of these robots including their control cabinet units are operated on each individual car body assembly line.

The space constraints presented a challenge, with a small construction space combined with a high level of flexibility, was the challenge faced by the project engineers at Jäger Elektrotechnik when they were seeking the ideal components for control cabinets. "The 24 V control voltage also needs a separate fuse for each circuit even in these compact units. Thanks to our longstanding working relationship, we knew Lütze as the manufacturer of the current control system LOCC-Box from other projects. Its narrow construction width of 8.1 mm per channel, it’s great flexibility due to the settable current value and the single-channel design fulfilled all our requirements," says the Managing Director Robert Jäger. All the various control cabinet types can be individually configured with just one fuse type. Depending on the application, various fuse channels can be used without having to leave secured outlets unused due to the block design. The wiring, with cage clamps, ensures a durable and reliable connection to the connecting cables.

More than 8,000 LOCC-Boxes are planned and in some cases installed on the production lines. Each one of these is set individually to the matching current value and also to the necessary trigger characteristic, thanks to the patented analogue characteristic curve. "The 5-step option allowing selection from fast to slow characteristics facilitates optimum protection of each separate circuit," explains Martin Baum, Lütze Sales Engineer. This not only secures the reliable operation of the system, but also ensures prompt shutdown of each circuit in case of an error.

The LOCC-Box enjoys a high level of acceptance in many areas of the automotive industry. There are also numerous machine and plant construction manufacturers that rely on intelligent LÜTZE current control systems for individual and reliable protection of DC circuits. Different variants also allow their use for safety relays, circuits that comply with UL, applications from 0.2 A, or DC networks between 12 V and 48 V. Thanks to LOCC-Box, the optional connection to the normal field bus systems is improved, also saving on wiring. It is even possible to set up early warnings as triggers for preventive maintenance. The uniform casing of all LOCC-Box types also gives the company Jäger Elektrotechnik the security that it can expand its existing systems at any time and adapt them to the new requirements.

Martin Baum, Sales Engineer at Friedrich Lütze GmbH
Figure: LOCC Box - Intelligent current control in car body shops