Maximise safety performance
05 August 2015
To achieve the maximum safety performance level PLe, a category 3 or 4 architecture must be used.
What this means for a servo system is that a second method for measuring speed is required, this is usually achieved by fitting an additional separate encoder or resolver to the axis increasing the costs and complicity to the system and set up process.
Due to its onboard safety card, the PMC Protego DS from Pilz is able to measure the motor current to determine its speed. This, combined with the feedback signal provided by any servo motor, constitutes a category 4 architecture. This means that using the PMC Protego DS drive and any servo motor it is possible to achieve PLe without any additional equipment.
The PMC Protego DS also has the following Safe Motion Functions included as standard: Safe Torque off, Safe Stop 1, Safe Stop 2, Safe Operating Stop, Safe Limited Speed, Safe Speed Range, Safe Direction, Safe Limited Increment, with Safe Braking functions and Safe Limited Position available as additional options.