Safety laser scanners: what are the most important requirements?

Already at the end of the 1990s, Leuze electronic presented the first "rotoScan." The laser scanner, which was brought to market as the rotoScan RS3, for the most part had the same housing then that it has today: this coffee-machine-like appearance is retained, even if the current devices are much smaller and more compact.

Leuze's rotoScan RS3 was touted as an area scanning distance sensor for the detection of objects and persons. This definition is still valid for the modern laser scanners of today. Even then, it was suitable for rail-mounted vehicles and driverless transportation systems. At the time, it was known as the "leading bumper." That continues to be true. And that is where the similarities end.

The first step is always the hardest: at the time, the RS3 was not safe in the spirit of the valid standards relevant to safety at work. It was desirable here in particular to be able to reliably safeguard a horizontal or vertical area using such a practical and compact device. With this goal in mind, Leuze electronic then started a further development that was to set new standards in personnel protection, in object detection and for navigation tasks. During this phase - about 15 years ago - Leuze electronic gathered enormous experience in the area of safety laser scanners that continues to be applicable today.

A big success on the market in the years that followed was the ROTOSCAN RS4 safety laser scanner and its "red brother," the ROD4, which was designed for measurement tasks in non-safety areas. The RS4 product family was marketed with the slogan "flexible multitalents for people safety." Unlike the predecessor, the weaknesses had been successfully eliminated and a versatile device placed on the market - it was certified according to the latest international safety standards and convinced with previously unknown function packages, e.g., MotionMonitoring, three different operating ranges (up to 6.25m) and even then with integrated interfaces for Profisafe and AS-i Safety, i.e., with "integrated connectivity" - a term that is today closely linked to Industry 4.0 jargon.

"thinkmodular"

It is, thus, no surprise: with the RS4 series, Leuze electronic celebrated success around the world. And that is precisely where the manufacturer continues with the new RSL 400 series, which was presented for the first time in 2014 at the SPS IPC Drives trade show in Nuremberg. It consists of 16 device versions in four staggered operating ranges (S, M, L, XL) and four function variants (RSL 410, 420, 430, 440). In this context, Leuze electronic speaks of "thinkmodular" - a philosophy that the manufacturer also successfully implements in other product series, e.g., with bar code readers and smart cameras. With the laser scanners, this means: whether stationary or mobile, whether long or short operating ranges, basic functions or high-end equipment - the user obtains what is essentially a tailor-made device that can easily be replaced in the event of a device upgrade due to complete compatibility within the series.

The thrust of the optimisation measures lies above all with the following objectives: staggered increase in the scanning ranges (operating range, scanning angle), offer application-optimised functions, considerably simplify commissioning and handling. The development goals set by Leuze electronic are the result of many years of application experience and the voices on the market. For example, users in the sensor sector call for high-performance with very simple operation in addition to maximum reliability. The specification is finished. But what does the requirement specification contain?

While the predecessor ROTOSCAN RS4 handled an operating range of 6m, the RSL 400 safety laser scanner manages 8m without problem. With a maximum operating range of 8.25m, it offers one of the largest operating ranges of any laser scanner on the market. In combination with the scanning angle of 270 degrees (its predecessor, the RS4: 190 degrees), the result is an enormous safe scanning range of 160 square meters.

This satisfies even the most demanding users - for the time being at least. This is because, compared with the RS4 laser scanner, a doubling of performance is achieved in a significantly more compact design, as is so often required in practical use.

The scanning angle of 270 degrees offers a special feature: the large angular area is particularly advantageous when mounting on corners or edges to safeguard to the front and side - especially in combination with the large operating range. All-round safeguarding of a corridor supply vehicle, a machine or a system can, as a result, now be achieved with just two laser scanners. Previously, with devices with scanning angles of 190 degrees, four scanners were necessary for this purpose.

Leuze electronic claims the RSL 400 is a device that performs the work of two. This statement can be verified: in addition to the aforementioned savings achieved through the large scanning angle, the RSL 400 features two configurations that can be set independent of one another (so-called autonomous protective functions) and two safety-related switching output pairs (OSSDs). This allows two completely different protection tasks to be performed simultaneously with just one device, since two switch-off circuits or separate areas can now be monitored and switched off. This is easy on the wallet and is good for purchasing, maintenance and commissioning. And in these areas in particular, the new series offers still more advantages.

Commissioning made simpler than ever

Laser scanners are still considered to be difficult when it comes to set up and start up. The manufacturers are now responding to this. Leuze electronic has therefore invented the CU 400 intelligent connection unit. It is the mechanical and electrical base (black substructure, see figure) for the safety laser scanner (yellow, on top) and handles all cable management. During mounting, the laser scanner unit is simply removed and the rugged connection unit secured to, e.g., a side-tracking skate, the wall, the ceiling or at the system entrance with standard tools. The scanner unit is then put back in place - mechanical mounting is finished.

Should a device upgrade be necessary, the user can simply dismount the scanner unit and replace it with the desired model. The connection unit, on the other hand, remains securely mounted and aligned and thus retains all electrical and mechanical settings and configurations. It can be quickly fitted with a different laser scanner - without tedious realignment, complex readjustment and without an annoying configuration marathon. These are important points for maintenance and servicing.

During alignment and adjustment, assistance is provided by a large plain-text display with integrated electronic spirit level. The days of connecting a PC and fiddling with the device for a long period of time are definitely in the past - at least with respect to the mechanical connection and alignment.

For the safety configuration, a PC and a small piece of software are still necessary. Leuze electronic saw potential for optimisation here as well: with its Ethernet interface, the devices are fully network capable. In addition, the safety laser scanners can be easily configured wirelessly via Bluetooth. This was never possible before.

Despite the large number of possible field pairs (100), the creation of independent configurations with the application-oriented one-step configuration is simpler than ever. With just five mouse clicks, the laser scanner runs in a simple safety configuration, which can, of course, be expanded as desired. This software wizard, with just a small number of presets, handles the automatic creation of protective and warning fields - an important advantage for many users who do not require any complex configuration. And the best is: when changing the operating mode (you recall: the laser scanner masters two autonomous protective functions), no reconfiguration is necessary, thanks to the so-called multi-configuration. Of course, the user is supported during all steps in the software by a detailed information area with automatic, context-sensitive online help.

Summary and outlook

Leuze electronic has known safety laser scanners, the ultimate discipline in safety sensor technology, right from the very beginning when this technology found its first users. The RSL 400 series incorporates decades of experience, resulting in excellent performance data and unsurpassed usability - the application of such multi-talented sensor technology has never been easier.

All devices demonstrate a high level of availability on account of the high resolution and a high insensitivity to dust thanks to the high scanning rate. Nevertheless, Leuze electronic is already working on the further development - after all, Industry 4.0 has given the manufacturers plenty of homework. For example, there will be even more in the way of connectivity in the future and, as a result, further Ethernet-based interfaces will follow.

Follow the link for more information about the RSL 400 safety laser scanners.