Circuit arrangement for failsafe monitoring of a stored-program press safety control

摘要

The aim is to utilise the advantages of stored-program technology and to use commercially available stored-program control facilities without additional interfaces and devices for synchronising and comparing the program sequences of both controls. The object lies in the failsafe monitoring of the two stored-program control facilities without additional equipment expenditure and in a failsafe actuation of the press safety valves. According to the invention, this is achieved by the fact that the failsafe monitoring of the equivalence, time-shifted by a maximum of one cycle period, of the outputs (A2; A2' to An; An') of the stored-program control devices (2; 2'), which operate independently of one another, is created with the same programming by outputting certain identical program points at the outputs (A2; A2' to An; An') to the external comparators (7) of the monitoring channel and that the respective output (A1, A1') for actuating a press safety valve (5; 5') is conducted to a safety amplifier (4; 4') which must be enabled by the monitoring channel. <IMAGE>