Failsafe Safety Wiring Scheme for Robots
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-14
Robotic systems frequently provide means in the form of safety mats, light curtains and the like, to shut down robot movement if any operator enters the workspace of a "live" active robot. In the drawing, four safety mats M1-M4 are coupled in parallel with the windings of relays 1 and 2 of a pair of robots (not shown). Relays 1 and 2 and M1-M4 are normally energized via grounded pin AG resistor R1 and positive 24 voltage supply pin. If an operator steps on any mat, it short circuits the windings of 1 and 2 to close their contacts, thereby applying ground potential to pin X of each robot to cause an emergency stop of the robots. A similar emergency stop occurs if any of the wires are broken or short circuited.