Emergency robot shutdown circuit

摘要

An emergency robot shutdown circuit reliably stops a movable component of a robot which has suffered an overtravel condition. The emergency robot shutdown circuit has three relays, and detects an overtravel condition of the robot with a dog located in a limit position of a normal operation range of the movable component of the robot to command an emergency shutdown of the robot. The second relay holds an overtravel signal which is outputted from a detecting circuit. A switching transistor is connected parallel to a make contact of the second relay, and an overtravel cancel switch is connected parallel to another make contact of the second relay. The base of the switching transistor is supplied with an overtravel unlatching pulse in synchronism with the closing of the overtravel cancel switch. The third relay, which is connected in series with the other make contact of the second relay, has three make contacts which make up a power cutoff circuit. These three make contacts are turned off only when the third relay is de-energized.