Apparatus for controlling system state based on unique identifiers
AssigneeSandia Corporation
InventorWilliam D. Drotning
Life of this patent
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Abstract
An apparatus allows workers to assert and release control over the energization of a system. The apparatus does not require the workers to carry any additional paraphernalia, and is not be easily defeated by other workers. Users asserting and releasing control present tokens uniquely identifying each user to a reader, and the apparatus prevents transition of the system to an undesired state until an appropriate number of users are currently asserting control. For example, a dangerous manufacturing robot can be prevented from energizing until all the users that have asserted control when entering the robot's controlled space have subsequently released control when leaving the robot's controlled space.
Claims19
An apparatus for allowing a plurality of users to assert and release control of the transition of a system from a first state to a second state, comprising:
- a) token means for reading tokens, where each token is uniquely controlled by one user while such user is asserting control of the system, and
- b) lockout means for preventing the transition of the system from the first state to the second state until a selected pattern of tokens has been read by the token means.
An apparatus to prevent the transition of a system from a first state to a second state based on the presence of users, where each user has a uniquely associated token with information uniquely identifying the user, and where the system comprises a controlled space, said apparatus comprising:
- a) reader means for reading identifying information from tokens;
- b) discrimination means for discriminating between tokens of users entering the controlled space and tokens of users exiting the controlled space;
- c) determination means for determining a first number of tokens read entering the controlled space and not subsequently read exiting the controlled space;
- and
- d) lockout means for preventing the transition from the first state to the second state if the first number reaches a predetermined value.
An apparatus for preventing the energization of equipment based on the actions of a plurality of users, comprising:
- a) input means for allowing a user to enter identifying information and to indicate whether such user is asserting or releasing control of the energization of the equipment;
- b) determination means for determining a first number equal to the number of users that have asserted control of the energization of the equipment that have not subsequently released control of the energization of the equipment;
- and
- c) lockout means for preventing the energization of the equipment unless the first number reaches a predetermined value.
Dependencies are inferred from the claim text.