Drives & Controls June 2022

L asers are used widely in commercial and university laboratories across the UK for a wide range of purposes including research and measurement. As a result of health and safety issues relating to their use – including possible retinal damage – safety precautions need to be deployed. One way of achieving this is to use interlock systems that prevent unauthorised access to laboratories while a laser is in use. The interlock must also allow the continued and safe operation of the laser without supervision, which may be required, for example, during scientific experiments. Interlock systems allow lasers to be used safely when operators aren’t present by protecting the operating area from unauthorised access. To suit locations that can vary from university laboratories to wind tunnels, and still provide safe and simple use, they need to be secured inside appropriate enclosures. These housings have to provide the necessary protection and must also offer the installation flexibility to be able to adapt to the layout of the host environment. The Scottish firm, Laser Support Services, based in Ovenstone, was founded more than 30 years ago to support laser users across various sectors and applications, from educational research to health applications and military installations. Before 2013, the Scottish company resold third-party laser interlocks, but in that year it launched its own system. The interlock consists of a main controller for the laser’s power supply; a door controller that authorises entry to the laboratory where the laser is in use; and a keypad that allows outside access to the lab. Each element has to be housed in a safe, durable enclosure that can accommodate the layout, configuration and space constraints of each laboratory. Because the settings differ for each interlock installation – which may be in existing buildings or in new developments – the positioning of the various control elements needs to be flexible. At the same time, the systemmust remain safe and simple for laboratory staff to use. The system’s door controller allows 30 seconds for personnel to leave a laboratory, so the closer the device can be positioned to the door, the safer and easier the system is to use. The laser interlock’s main controller comprises a master key switch and an E-stop, as well as energise and de-energise functions for manual operation. It also incorporates an LCD display that shows the system status and any faults. Each of these user interaction functions is built into an enclosure configured for the required mounting position. Laser Support Services typically uses enclosures made from lightweight polystyrene or durable, glass-fibre- reinforced polycarbonate for more rugged installations. While the reinforced polycarbonate enclosures meet IK08 impact ratings – among the highest available – the polystyrene versions still achieves IK07, and will resist impacts from 0.5kg weights dropped from a height of 25cm. Both types of enclosure also provide ingress protection up to IP66, giving them the flexibility to be installed in a wide variety of environments. Laser Support Services uses enclosures supplied by Spelsberg.“We have to adapt the interlock system for individual laboratory requirements,”explains Laser Support Services’ founder and managing director, Grahame Rogers.“Spelsberg provides boxes that are flexible and very simple to use, making them adaptable and suitable for every laser interlock project. Various mounting points enables flexible installation, combined with an in-house CAD service when required.” While Laser Support Services typically uses standard enclosures, Spelsberg offers a customisation service for fast turnaround of bespoke designs. Even with knock-out holes and customisation, the enclosures achieve the high environmental protection that is crucial for safe laser control. Gaskets protect the internal components from external moisture, and can operate in 95% humidity at 25°C. n 42 n SYSTEM INTEGRATION AND PANEL-BUILDING June 2022 www.drivesncontrols.com Interlocks allow laser beams to be used safely Safety interlocks are vital to protect users of laser-based equipment. A Scottish company has developed a flexible interlock system that can be adapted for installation in almost any environment. Laser Support Services’ interlock systems help to protect laser users from potentially harmful exposure to the powerful beams