Servo drive achieves PLe safety level at minimal cost

08 August 2015

The new PMC Protego DS from Pilz is able to measure the motor current to determine its speed. Used with any servo motor it is possible to achieve safety performance level PLe without any additional equipment.

In order 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 costs and complexity.

Thanks to its onboard safety card, the PMC Protego DS 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. By 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.

With free configuration software the PMC Protego DS is straight forward to configure for motion tasks and safety features alike.