Patent ID: 6992458
Filing Date: 2006-01-31
Classification: H01H

Abstract:
1. An emergency stop circuit comprising: two emergency stop lines, each of which is connected with a contactor; and a power supply circuit for supplying power to a motor for driving a machine from a power source via series circuits composed of contacts of respective contactors, wherein on each of the emergency stop lines, a contact being opened when an emergency stop command signal is inputted from an emergency stop factor, and a contact being opened by a command from a CPU provided to each of the emergency stop lines, are connected in series to thereby connect the contactor with the power source, the emergency stop circuit includes detecting means, with respect to respective contacts, for detecting states of the contacts, and each of the CPUs outputs a command to open a contact on a self emergency stop line when information about the states of the contacts of the self emergency stop line, detected by the detecting means, and information about the states of the contacts of another emergency stop line, transmitted from another CPU, do not coincide with each other.