Anyone putting together a kitchen in the online configurator today will experience modularity in its purest form. The individual modules are in turn made up of modules for the side panels, base panels, back panels and shelves. At the end, you can choose from various decors for the fronts and panels, a handle design and a matching worktop.

This example clearly shows that modularity is inconceivable without standardization. Only when defined distances, dimensions, drill holes and connections for water or gas are available can the advantages of a modular production strategy be exploited: a wide range of variants and flexibility with short throughput and delivery times and moderate prices.

Matthijs Varwijk uses these and other arguments to convince interested parties and customers of the modular machine concept. Varwijk is R&D Project Manager and also responsible for the modularization strategy at Dutch machine manufacturer AWL-Techniek in Harderwijk. With more than 750 employees at five locations worldwide, AWL has made a name for itself with its automated welding and joining lines, particularly in the automotive industry. Major car manufacturers, suppliers and many other customers worldwide use the Dutch company's machines in their production lines.

In 2017, an interdisciplinary team led by Varwijk converted AWL's machine portfolio to modularity and gradually defined the standards for the new line. Initially, he also had to do some convincing internally. Especially in the transition phase from the classic to the modular production layout, the advantages are not always clearly recognizable. First of all, standards have to be defined, which is often associated with restrictions.

AWL set the first standard with the name of the product range: on the one hand, the M-Line stands for a modular product range; on the other hand, the term "line" also symbolizes the production line into which the individual modules are assembled. The basis of each module is a steel frame cuboid, which is dimensioned to fit into an ISO container. This saves a lot of time and money when transporting and commissioning the machine. The customer can also easily expand or convert the system at a later date, as the modules can be rearranged in the production hall using appropriately designed forklifts.

Modularization needs standards

Three central module types were defined with the basic frame, from which the M-Line is to be assembled: an operator module, in which a worker can insert components and start processes, an indexer module, which includes rotary tables or other devices for handling the workpieces, and a process module, which processes workpieces with welding robots or other tools, for example. AWL benefits from Turck's Ethernet multiprotocol technology for I/O modules. It allows the manufacturer to use identical I/O block modules in each module of its M-Line - regardless of whether the customer prefers a Profinet or Ethernet/IP controller. "We wanted as many standardized components as possible and also a largely standardized control cabinet. Ideally, one day we will only have one PLC and one power supply unit in the control cabinet," says hardware engineer Jasper van Kooij. We haven't got that far yet, but there is already plenty of room in the control cabinet for the AWL modules. The IP67 I/O hybrid components for standard and safety signals from Turck also contribute to this.

AWL was impressed by the concept of a modular IP67 IO-Link safety solution: the TBPN hybrid safety I/O module forms the core of the solution. The module has an integrated safety controller that communicates with Profisafe via Profinet. The module has four safe I/Os, two classic digital I/Os and two IO-Link ports. The TBSB safety switch-off box is connected to one of the safe I/Os, which safely switches off the actuator voltage V2 in the event of an emergency.

The power supply for all modules also runs via the safety switch-off box. This ensures that in the event of an emergency stop, for example, no actuator is supplied and nothing can move in the machine. The sensors remain active as they are supplied via V1. This means that the machine is always visible in the control system. The digital sensors and actuators of the welding cap cutter are connected to I/O hubs, which in turn communicate with the Turck IO-Link master TBEN-L-8IOL. The IP67 block provides four IO-Link ports according to the Class A and four according to the Class B standard. The latter separates the voltage for sensors (V1) from the actuators (V2). This means that the power supply can also be safely switched off via IO-Link. AWL has already used the TBIP module in similar projects in the USA. It has the same hardware as the TBPN, but is designed for EtherNet/IP and CIP safety communication.

Sensor and actuator voltage galvanically isolated

"Other manufacturers also have modules that supposedly have V1 and V2 separated. But if you take a closer look, it's not consistent and V1 and V2 share the negative pole, for example," says van Kooij. The split earth can be fatal in the event of a short circuit. A simple insulation fault is then enough to undermine the entire safety solution - one of the reasons for the completely galvanically isolated system. "Only Turck was able to offer us the complete range and consistently separated V1 and V2 circuits."

By using the IP67 solution including safety and I/O hubs with IO-Link, AWL saves a lot of wiring work. As IO-Link devices, the distributors transmit digital signals from actuators and sensors in the IO-Link protocol and bring them to the IO-Link master, from where they reach the controller via Ethernet. Another reason for van Kooij and Varwijk was that the bidirectional interface promotes the standardization of the M-Line. The secure signal transmission via three-wire cables makes many specially shielded cable types and special cables superfluous. IO-Link also ensures greater machine availability: part of the M-Line is the Lyla dashboard system. It collects data from various machines, evaluates it and thus monitors the function and performance of the machine. This is also made possible by the diagnostic data via IO-Link.

Global automation partner wanted

AWL is building the current M-Line generation for a German car manufacturer and its supplier. In addition to the IP67 concept, the Dutch company appreciates the fact that Turck, as a globally positioned automation partner, can also offer and support the same solutions for automotive projects in the USA, Mexico and China as in Europe. "We need a partner that also suits us globally. We have found this in Turck," says Matthijs Varwijk.

Modularization of the control level is still pending. So far, every control project has to be set up from scratch; only function blocks can be reused. However, the modularization project is never finished anyway. AWL customers have already accepted the M-Line very well. They see the scalability of the machines as a major advantage. It is no problem to replace an operator module with an automated solution at a later date in order to increase output.

Michael Flesch, Product Manager Safety Systems, Turck

SPS, Hall 7, Stand 250