Machine builder finds IO-Link fast, easy and cost-effective

>UK Machine Builder Advanced Tooling Systems and its control panel builder DMC Controls have implemented IO-Link - a 'connect instead of wire' system - into their build process and are now seeing a reduction in the machine build time and complexity as well as reducing the size of the control panel and cost of components used. IO-Link is also ideal for just-in-time production environments making it easy to identify and solve problems very quickly with the advanced diagnostics available.

>"With 2012 being our most successful year to date we had to look at ways to increase our throughput," says Adrian Gander, managing director of Advanced Tooling Systems. Specialising in edge wrapping machines for automotive customers, he has first hand experience of the enormous amount of production time and effort involved with fitting out and wiring a machine densely packed with IO. Advanced Tooling Systems has been manufacturing edge wrapping machines for automotive and medical customers since spotting a gap in the market over seven years ago. The machines typically finish or 'edge wrap' a moulded plastic component with cloth or leather.  

>"When we first entered the edge wrapping market we could see that most customers could only buy from one source and changing their process to suit the available machines," says Gander. "By looking at the whole process in more detail and working closely with customers we have developed a bespoke solution that reduces the process from 20 minutes to around two minutes, without a reduction in quality. The good customer feedback on quality, functionality and durability has given us the impetus to look to expand into the European market."

>In the edge wrapping process, the material is applied to the substrate, trimmed, loaded into a nest where it is clamped and then swept over by pressure pads which hold the material in place without creases. The press operation can be hot or cold depending on the adhesive type and materials used. Edge wrapping machines automate a traditionally labour intensive operation leading to a much more repeatable process whilst reducing the skill levels required for operators.

>The requirement to increase production led to a review of the control system and Advanced Tooling Systems turned to sensor and connectivity specialist Balluff for advice. Balluff regional sales manager Toby Horne takes up the story: "A machine with a level of automation such as this requires a comprehensive set of positioning, status and control queries at each station. For example a number of sensors check if the substrate is in the correct position, if a folder is in or out and whether a pressure pad is in the correct position. With such a significant amount of IO on even a relatively small machine there were large bundles of cables routed in trunking. This in turn meant that every sensor and actuator had to be terminated in the panel and then wired into PLC IO cards. The first step that we took was to reduce the number of cables and the wiring time by connecting sensors to passive pre-wired splitter boxes."

>This allowed for a significant reduction in wiring at the panel as the power signals for the IO are shared and only a single cable for each IO device had to be terminated in the panel. Another benefit was the reduction of cables in the trunking on the machine as each pre-wired splitter box has a single multi core cable running back to the panel.  Horne continues: "Although this approach was successful on a couple of machines, we felt that there was a greater improvement to be made by developing the solution to use a Profibus system with IO-Link as the final connection to the sensors and actuators."

>The fieldbus-neutral and manufacturer-neutral IO-Link interface is a powerful digital point-to-point connection for simple and clear relationships below the bus level. In conjunction with an IO-link master, which appears as a bus node, the serial interface requires only common unshielded, three core cables to connect to IP67 sensor hubs which can each support up to 16 IO, or IO-Link enabled devices. IO-Link is downward compatible to all standard sensors and is insensitive to electro-magnetic interference. Shielded cables and special cables are completely omitted from the installation as are additional junction boxes.

> Instead of running individual sensor and actuator cables back to the panel, an M8 or M12 plug is used to connect the IO to the sensor hub and the sensor hub to the IO-link master. A single bus cable is routed back to the control panel and fed into the PLC. The installation process takes a fraction of the time and in addition to savings in the size of trunking, the number of terminations in the panel and reduction in panel size, PLC input and output cards are no longer required. Add to this the flexibility of being able to combine digital and analogue IO signals and to add IO-Link enabled devices such as RFID readers, pressure transducers and valve manifolds to the system together with the ability to parameterise IO-Link devices over the bus and you have a very flexible system.

>Dave McGoldrick of DMC Controls who provide the control systems for Advanced Tooling Systems says: "The introduction of the Balluff IO-Link system made a big difference to the way we build the machines. With a 'connect rather than wire' philosophy the installation time for the IO has reduced from around three weeks to one week, the control panel has halved in size and we see more than a 32% reduction in the panel component and build costs. Just to make the bundles of cables look neat inside the trunking used to take two days but now there are very few cables to be seen. The IO-Link system is very straightforward to configure using standard software tools and Balluff offered really good support on the initial system set-up."

>From the end user perspective, in addition to the quality of the finished part, the quality of the machine itself and its production 'up-time' is critical. Gander comments: "Our machines must be maintenance friendly.  In a just-in-time production environment any down time is critical and highly visible. If you get a problem with our machines equipped with the IO-Link interface it is very easy to identify and solve very quickly with the advanced diagnostics available."

>The IO-Link interface allows for configuration and advanced diagnostics from a distance which is a great advantage in areas that are difficult to access. With IO-Link, sensors and actuators can be replaced 'on the fly' and newly inserted devices get their parameters directly from the control level. Many of the Balluff IO-Link masters include an integrated web server to make remote connection possible from anywhere in the world.