The Potential of Clever Ethernet Interfaces
Published by : Industrial Automation
How a clever and space-saving design permits this innovative interface to accommodate 24 ports, rather than 12, in the same space.
The eXtended Transport System (XTS) by automation specialist Beckhoff from Verl combines the advantages of linear and rotational drives, thus offering a compact solution for innovative machine concepts. The key aspect of this innovative solution is that customary drive components trade places. While electrically connected movers usually travel on static magnetic rails in most linear drives, the XTS system works exactly the other way round. Its three main components are a static linear motor, a guide rail that is parallel to it, and the passive mover itself. This concept makes the XTS system the first linear drive to travel in circles. Being independent passive carriages that need no data or power supplied by drag chains or sliding contacts, the movers are able to travel along straight as well as curved routes. This enables the creation of closed loops that bring much greater efficiency. While linear systems will usually feature a forward run and return journey, movers can reduce empty runs in a loop, markedly boosting the system's effectiveness.
The XTS comprises three main components
The XTS motor provides a fully integrated fusion of power electronics and routing, where magnetic coils are activated in a controlled manner to set a passive mover in motion through a double air gap. The motor can accelerate the movers to speeds of up to 4 m per second, and that with precise positioning. Regardless of whether the route is straight or curved.
The motor modules are always combined with matching guide rails to give them the correct guidance. Depending on the application, carriages can either be moved on the inside or outside radiuses.
The mover is the third component and features the magnetic plates required to generate the propelling force in combination with the motor module. A clever geometry and opposing magnetic field exciters ensure that the bearing is exposed to hardly any propelling forces, even in heavy-duty applications. This will not only preserve the bearing, but also save operating power for the application.
There is hardly any limit to the possible applications of the XTS – The movers can accelerate, brake, position and synchronise themselves; they can assume absolute and relative positions to one another; they can group and queue; they can generate clamping forces in motion; they can travel in curves just as fast as straight lines; they are able to recoup energy by regenerative braking, and use their return journeys for transport just as much as their forward runs. All this is precisely position-controlled, without vibrations, without slack, without material fatigue, with hardly any wear – and without cost-intensive maintenance.
While conventional transport systems rely on many bearings, chain drives, conveyor belts, trailing cables or sliding contacts requiring regular maintenance, the XTS works with a minimum of mechanically moved parts.
Flexibility – which also makes format adjustments much easier when products are changed, for example. And creating new transport routes will only require the ready-made motor and rail components to be reconfigured. If the route remains the same while the product parameters change, this can be accommodated by a simple adjustment in the software parameters.
Safety – conventional transport systems are driven by belts, chains, and the like. This often involves long stretches of mechanically interconnected transport media. The drive then needs to supply the full force required for all these transport devices, i.e. the sum of all the individual forces required by all the components. If a malfunction, collision, or similar event occurs now, the total force of the entire system will logically be acting on a single point. Such forces can quickly lead to major destruction. Whereas with the XTS, the only force to be ever applied is the individual force of the mover, which is much weaker. This considerably improves the operational safety.
This linear motor principle opens up completely new perspectives in the drive technology:
– Linear motor characteristics also in closed loops
– Several movers on the same route
– Modular structure, easily customised for the application
– Needs little space and energy
– Easy realisation of demanding transport tasks, and
– Little outlay for project planning and assembly.
From 12 ports make 24 – with HARTING ix Industrial
While the movers are travelling and following their scheduled movement pattern, i.e. unlocking, clamping, releasing, braking, etc., a computer constantly needs to calculate the switching and energisation of the responsible motor modules. The XTS allows three computer cards to be combined for this altogether, which used to feature four RJ45 sockets each in the past as ports. Every port usually serves to control a motor module length of 1.5 m. But even while user requirements are constantly mounting where the size and complexity of planned transport tasks are concerned, the compact dimensions of individual components should still be maintained. This is where the connection technology specialist HARTING from Espelkamp proved able to furnish a suitable solution with its ix Industrial® Ethernet connector.
The interface inside the appliance is at least 50% smaller than RJ45 interfaces, but much more robust, and equipped with a stable mechanical locking device. The 5,000 possible plugging cycles may be irrelevant for Beckhoff in this project, but still underscore the robust design of the interface. The power supply by PoE/PoE+ is just as safe as the reliable retention on the circuit board, ensured by several shielded THR contacts. Based on IEC 61076-3-124, the ix interface is an open standard, rather than a specialised, isolated solution. Anything but a standardised solution was out of the question for XTS.
Besides the tremendous space savings per port and more robust interface, the key requirements for the XTS system also included reliable shielding and outstanding data transmission rates. With the contacts so closely packed together in this small design, 1/10-Gbit/s Ethernet interfaces always present particular challenges in effectively minimising crosstalk between individual data pairs. This is ensured by a shielding concealed between the two contact banks. Crosstalk is effectively excluded. In addition to which the new HARTING ix Industrial® features 10 contacts, 8 of which transmit data, while 2 are connected to the ground potential on the circuit board, and serve as a further shielding. The shielding plate and earthed contacts let the arrangement of the signal-carrying contacts resemble that for an x-coded M12 circular connector. Each wire pair lies in its own cable or rather connector quadrant, perfectly shielded from its neighbours. The arrangement provides effective crosstalk protection while realising perfect data transmission.
This particularly good shielding is turned to account for the XTS system, with every HARTING ix Industrial® connector realising two 100 Mbit EtherCAT connections.
What this enabled in the big picture is the accommodation of 8 ports on the same circuit board, rather than 4, and provision of 2 EtherCAT channels per port instead of 1. Projected onto three circuit boards, you end up with 24 ports on the bottom line, supplying 48 EtherCAT lines instead of the former 12! And thus the possibility of realising driving distances measuring up to 100 m. This highlights the tremendous potential of miniaturised and high-performing Ethernet interfaces for IIoT and I4.0 applications. Especially because automation components are shrinking in general, but expected to become ever more efficient and powerful at the same time. HARTING provides Beckhoff with its ix Industrial® interface for this, and Beckhoff its clients with an innovative transport system that redefines the possibilities of linear systems from the ground up.