Security system
AssigneeJokab Safety AB
InventorsMats Linger, Göran Svensson
Life of this patent
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Abstract
The present invention relates to a programmable safety system intended to be used for safety functions, in which a fault in a control circuit does not lead to a safety function being disabled, which system comprises monitoring functions containing at least two control units, input terminals separately coupled to both control units, whereby each control unit executes its own instruction set and continuously compares a result from the execution with each other. At least one control unit can access the in and output terminal status of a second control unit and/or a number of flags, and the control units are arranged to monitor the result of respectively executed instruction sets and control that the results of the executions are substantially equivalent.
Claims26
A programmable safety system having safety functions, in which a fault in a control circuit does not lead to a safety function being disabled, said system comprising:
- a first and a second control unit, for monitoring functions, inputs separately coupled to both of said first and second control units,
- each of said first and second control units being arranged to execute its own instruction set and continuously compares a result from said own execution with the other ones execution,
- said first control unit being arranged to access status of an input and output terminal of said second control unit and/or a number of flags said first and second control units being arranged to monitor a result of respectively executed instruction sets and to control that the results of the executions are substantially equivalent, and
- each control unit comprising means for controlling a respective relay via separate transistors.
A method in a programmable safety system intended to be used for safety functions, in which a fault in a control circuit toprohibits disablement of a safety function, said system comprising monitored functions containing at least two control units, input terminals separately coupled to both control units, whereby each control unit executes its own instruction set and continuously compares a result from the execution with each other,
- the method comprising the steps of:
- making available at least in and output terminal status of a second control unit and/or a number of flags for a control unit,
- supervising by said control units a result of each respectively executed instruction set,
- controlling that the results of said executions are substantially equivalent,
- and controlling by each control unit a respective relay via separate transistors.
Dependencies are inferred from the claim text.