DAC102021

42 n MACHINE BUILDING October 2021 www.drivesncontrols.com Switch to decentralised I/O saves panel space and simplifies wiring for automation firm N orwich-based Mills CNC splits its business between suppling and servicing Doosan machine tools, and its automation systems division, which specialises in industrial and collaborative robot systems. “The addition of the automation systems division presented us with a wealth of new opportunities,”says controls and systems engineer, Chris Ingham.“Our aimwas to make automation more accessible. Our systems are flexible and powerful, but what sets us apart is that our automation solutions are simple to understand, program and operate.” Initially, Mills electrical used components, including IP20 I/O, from a variety of suppliers inside the control panels for its Synergi automated manufacturing cells.“Our cabinet size was dictated largely by the requirement to house the I/O,”Ingham recalls. But the company wanted to rationalise this approach to simplify the wiring, and reduce wiring times. Mills decided to decentralise the I/O points outside of the cabinet, and thus to simplify the wiring. Its systems offer multiple options for users, so the I/O system needed to be both flexible, and compatible with the Fanuc robot controllers that Mills uses. With most of the I/O now being located in the field, control panel sizes could be reduced, the wiring became more efficient, and commissioning became more streamlined, especially when locating any issues, because the input or output is now localised to the I/O. Althoughmoving I/O out of the control cabinet might sound expensive, replacing the whole system is not as costly as it might at first appear. Because the core of every Mills CNC machine is the same, simple repetitive tasks are easy to perform. Due to back-up and recovery options on aWeb server, around 10-20% of software work only needs to be done once. Mill chose Murrelektronik’s Cube67+ I/O system, which avoids the need to perform a redesign, for example, when switching to a different customer-specified pneumatics manifold. Mills CNC started with a basic system with one node with two expansion modules – one for discrete I/O, the other to control a valve bank – and expanded from there. An optional upgrade makes Industry 4.0 easy to implement using a diagnostic gateway. The expandable system has the flexibility to add extra I/O, beacon stacks or IO-Link devices to maintain cross-system communications. If the user’s requirements change, the system can be expanded using modular add- ons. A single cable carries internal communications as well as input and output power, reducing the amount of cabling and containment needed. Built-in circuit protection and fault diagnostics can help to achieve lights-out production with minimal downtime. Pluggable M12 or M8 connections reduce the chances of wiring errors. If there is a problemwith a cable, the Murr system allows quick change-out of the now shorter IO cables because the expander can be positioned close to individual IO devices. n THE LEEDS-BASEDmachine-builder MailroomMachines manufactures mail-wrappingmachines used to package items such as catalogues, magazines and brochures. They consist of twomain parts: a feed station, where rolls of packagingmaterial are unwound; and a wrapping section, where the mailing pieces are enclosed in a protective layer. This activity is traditionally known as “polywrapping”, because plastic materials such as low-density polyethylene are commonly used to wrap the items. Mailroom decided it wanted to adapt the design of its Norpak machines to use paper as a more sustainable alternative to plastic wrappings. For the machine to support paper, the feed station had to be modified to accommodate rolls that are up to three times thicker than the plastic film rolls. In addition, the system tension needed to be adjusted. While polyethylene (PET) is flexible and malleable, paper wrappers are more rigid, and can tear and crease if the tension applied is too high or too low. To control the tension being applied, Mailroom chose an inverter – a Mitsubishi Electric FR-A800-R2R – which has dedicated winding and unwinding functions for roll-to-roll applications. The user only needs to input values for key parameters, which are adjusted via an HMI that provides real-time monitoring during operations. When new rolls of paper are needed, a micro-PLC (a Mitsubishi Melsec-iQ-F FX5UC) controls the loading and unloading operations. This PLC can perform positioning and advanced motion control functions for up to four axes. “The automation devices were extremely easy to install and use,” says Jones. “Also, our in-house programmer was able to quickly learn how to code and operate all of the equipment.” The resulting mail-wrapping machine can be integrated into different types of production line, and supports a wide range of applications. Mailroom Machines is working on a new project to further increase the efficiency and productivity of its wrapping machines. Converting a wrapping machine to use paper boosts sustainability Mailroom Machines’paper-based mail-wrapping machine reduces the environmental footprint of wrapping operations The distributed I/O can be set up and configured using a built-in Web server. The controller and I/O are integrated via Ethernet/IP.