Strongly fail-safe interface based on concurrent checking
First Claim
1. Fail-safe circuit branch for providing a signal having a safe state or a non-safe state, comprising:
- inputs for receiving at least two binary control signals (Si, Si*);
a source of a non-safe state (Fe) connectable through a basic chain (14,
15) to an output (Oi) when the control signals realize a predetermined combination;
a concurrent checker (17) providing an error detection signal (g1, g2) if the inputs of a pair of its inputs are at predetermined states; and
means (14, 14*) for providing a first input of said pair of inputs with a signal corresponding to the state of said output and the second input of said pair of inputs with a signal corresponding to the output of a duplicate chain of the basic chain, this duplicate chain reacting like the basic chain in response to the control signals.
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Accused Products
Abstract
The present invention relates to a fail-safe control interface including branches for providing signals having a safe state or a non-safe state. Each branch comprises inputs for receiving at least two binary control signals (Si, Si*); a source of a non-safe state (Fe) connectable through a basic chain of elements (14, 15) to an output (Oi) when the control signals realize a predetermined combination; a concurrent checker (17) providing an error detection signal (g1, g2) if the inputs of a pair of its inputs are at predetermined states; and means (14*) for providing a first input of said pair of inputs with a signal corresponding to the state of said output and the second input of said pair of inputs with a signal corresponding to the output of a duplicate chain of the basic chain, this duplicate chain reacting like the basic chain in response to the control signals.
13 Citations
9 Claims
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1. Fail-safe circuit branch for providing a signal having a safe state or a non-safe state, comprising:
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inputs for receiving at least two binary control signals (Si, Si*); a source of a non-safe state (Fe) connectable through a basic chain (14,
15) to an output (Oi) when the control signals realize a predetermined combination;a concurrent checker (17) providing an error detection signal (g1, g2) if the inputs of a pair of its inputs are at predetermined states; and means (14, 14*) for providing a first input of said pair of inputs with a signal corresponding to the state of said output and the second input of said pair of inputs with a signal corresponding to the output of a duplicate chain of the basic chain, this duplicate chain reacting like the basic chain in response to the control signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification