Safety relays, e-stops, protective door switches, and safety pull cords can be used to protect machine operators
The idea of protecting machine operators is certainly not new. Safety relays and safety devices like e-stops, protective door switches, and safety pull cords with redundant contacts have been around for a quarter of a century(1). What has changed is how these devices can be used to offer operator protection, increase machine uptime, and reduce installation, maintenance, and troubleshooting expenses.
Now that networking safety has been approved for 10+ years and has gained broad acceptance, machine builders have more options than ever before(2). The G10 safety module is another important building block in enabling machine builders to design powerful and easy-to-use safety solutions. The idea behind this module family is simple:
Develop a safety solution that allows machine builders to keep using the conventional safe input devices they have come to trust over the years while enhancing overall system flexibility and reducing implementation and maintenance costs.
Using a "less is better" approach, the result is a tiny safe input module that makes any conventional, redundant safe input device—e-stops, magnetic door switches, pull-cord switches, protective door switches, to name only a few—part of the Safety at Work solution. Take a look at our video "How to Use a Safety Module with Any Conventional Safety Device" to see not only how easy it really is to use a conventional e-stop or protective door switch, but also how quickly user feedback and diagnostics information, that was previously difficult to obtain, can be created using this approach. No complex, time consuming, and costly hardwiring where logic is defined by moving wires among multiple, inflexible safety relays. No need to guess which safe input caused a machine shutdown. No need to ever touch a wire if the safe logic needs to be modified or extended.
In the video, we make use of an inexpensive e-stop and an external stacklight, the same, conventional non-networked components machine builders have been using for years, and show you how easy it is to control the stacklight to annunciate the state of the e-stop. We also show you how easy it is to use a flashing reset button to guide the operator to perform this necessary operation once the e-stop has been released.
Visit our website for additional how-to videos and Safety at Work configuration examples.
1 According to Pilz, the self-contained safety relay was invented in 1987
2 NFPA 79-2002 explicitly mentions "Control Systems Incorporating Software and Firmware Based Controllers"