BACK-UP DEVICE OF PROGRAMMABLE CONTROLLER

• Main Author: UCHIDA TOSHIO
• Format: Patent
• Language: English
• Published: 14.06.1986
• Subjects: CALCULATING; COMPUTING; CONTROL OR REGULATING SYSTEMS IN GENERAL; CONTROLLING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS ORELEMENTS; PHYSICS; REGULATING

PURPOSE:To prevent the useless switching actions by adding a function which interlocks the automatic switching actions to a bus switching device which switches a using system to a stand-by system when the using system has a fault to continue the control actions. CONSTITUTION:A back-up device of a programmable controller contains the data memory devices 50 and 51 for using and stand-by systems, a bus switch control circuit 52 and a bus switching circuit 53 which works with a command given from the circuit 52. This back-up device switches a bus 102 to the stand-by side when a fault occurs. Here a bus switch control circuit 52 is provided together with an interlocking circuit 54 which is controlled by interlocking signals 300 and 301. Thus the bus switching actions are controlled. The using system is interlocked so that it is not switched to the stand-by system even though the healthy signal of the using system is inactive as long as the signal 300 is delivered. This prevents the useless switching actions with the back-up device.