Machine safety: casting some light on the matter
01 February 2012
Much is often spoken and written about the need to protect the assets of the manufacturing sector, those assets being principally the means of production and people engaged in the production activities. Simon Adams considers the roles that industrial warning beacons and sounders have to play in the maintenance of a safe working environment
The Machinery Safety Directive EN ISO 13849-1 contains a vast amount of information and lays down many requirements for machine builders and operators – all designed to ensure that the means of production in any manufacturing enterprise are installed correctly and operated in a safe manner. The Directive places an obligation on both machinery designer and operator to ensure that equipment is fitted with adequate safeguards to protect machine operators, and any other staff working in the vicinity of such production machinery, from accidental injury.
So, how do industrial beacons and sounders fit in with all this? At the time of writing, signal device manufacturer WERMA boasts the most extensive range of products in Europe that conforms to the new guidelines relating to machine safety. If the signal device on a machine is prioritised for safety purposes, the new Directive stipulates that the design engineer must include a safety value for the device in his risk analysis. WERMA now offers these safety values for more than 100 signalling devices, ranging from signal towers to visual, audible or combined signal devices in various sizes and designs.
The German technical testing authority, TUV has tested and certified these signal devices with exceptional results; in particular, all products achieve the best MTTFd (mean time to dangerous failure) value of greater than 100 years. MTTFd specifies the nominal operational duration until device failure, in accordance with the EN ISO 13849-1 safety standard.
Non-safety related applications
All WERMA signal devices are suitable for use in non safety-orientated signal and warning systems, in accordance with the Machinery Directive, and meet the requirements of all relevant regulations. But how can these devices be used to provide simple but effective protection for both machine and operator?
Thanks to its exceptionally wide range of optical and audible signal devices and accessories, the company can provide a solution to those machine safety monitoring problems where the key requirement is to offer local visual and audible warning to workers and supervisors that a machine is not running as it should.
Moreover, these products can be deployed to make a significant contribution to ‘Overall Equipment Effectiveness’ (OEE) monitoring and management tasks – in particular a new product called WIN (Wireless Information Network), which can be supplied as an accessory to WERMA’s popular KOMBI 70 and 71 signal tower ranges.
This ‘plug-and-play’ system basically consists of a transmitter module, or ‘slave’, which fits neatly into the Kombisign 70/71 signal tower. The slave transmits information relating to the changes in status of the different light elements of the tower, corresponding to the operational status of the machine to which it is attached. The information is transmitted wirelessly to a small receiver unit, or ‘master’, which is connected to a USB port on any available PC or laptop. Included in the WIN package is a software application, which, when installed, enables various reports to be generated, providing an analysis of machine availability.
Additional transmitter units (slaves) are simple to add to the system and up to a maximum of 50 signal towers and WIN units can be accommodated by a single master receiving unit. This provides considerable scope for users of the system, whether they have just two or three machines or stations equipped with signal towers, or a more complex manufacturing operation involving as many as 50 machines. Transmission range is a very respectable 300m clear line of vision, but as each slave acts as a jumper to the nearest slave, more complex factory layouts that may have potential transmission path problems, can be accommodated.
Machine performance monitor
Once installed, WIN can provide valuable machine performance data. For example, should a machine equipped with a signal tower develop a fault or enter a condition that forces the signal to switch from a ‘green’ status indication to one of ‘amber’ or even ‘red’, the moment that change occurs it is transmitted wirelessly and recorded by the PC or laptop to which the receiver is connected.
The time and duration of the status change, machine malfunction or error is stored and the software package supplied with the system allows simple but effective productivity and run-time analyses to be performed for each machine or station guarded by a signal tower.
Armed with such performance and operational data, the user gains a better insight into the running efficiency of his equipment, allowing him to take any necessary steps to improve efficiencies. And all the time, adequate precautions have been taken to optimise machine and operator safety, thanks to the application of warning beacons.
Simon Adams is managing director of WERMA Signaltechnik in the UK
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