Manufacturers seeking innovative ways to improve employee safety without hindering productivity now have a simpler, more cost-effective method, thanks to an interesting development from Rockwell Automation. The Allen-Bradley Guardmaster Minotaur MSR57P dedicated safe-speed monitoring relay is described by Rockwell as a ‘first-of-its-kind’ safety device that allows personnel to enter hazardous machine areas when there is residual motion. The device supports numerous input devices such as E-stops, light curtains, enabling switches and interlock switches, which detect demands on the safety system and initiate a stop request of the motion. It also monitors personnel in the hazardous area while the machine is in a safe-speed condition.
Users can configure the safety relay with either Allen-Bradley DriveExplorer software or via an HMI, using a variety of parameters to help meet specific application requirements, including safe direction, safe limited speed, and safe maximum speed with door control and monitoring.
For example, the relay can facilitate speedier access for operators by unlocking doors automatically when the speed of the machine is below a safe speed limit or zero speed is detected. It is suitable for both new and existing installations, and while it can be used with most standard drives, it is particularly effective when applied in combination with the ‘safe-off’ option available on Allen-Bradley PowerFlex drives. The relay monitors the speed of the motion via one or two encoders, depending on the level of integrity required. However, if an encoder is already installed it can monitor the same signals without requiring an additional unit.
The Allen-Bradley Guardmaster safe speed technology is now available as an integrated option in current releases of PowerFlex 750 Series ac drives and Allen-Bradley Kinetix 6000 servo drives, allowing customers to implement this safety feature across a wider choice of machine control platforms.