Abstract: A system and method for fail-safe transmission of safety messages through communication channels containing non-safety-certified equipment is disclosed herein. Consistent with the disclosed method, digital signatures and/or encryption are used to authenticate both the origin and content of the safety messages. A watchdog timer ensures transition to a safe state if authenticated messages are not received periodically. In a particular implementation, the disclosed method includes generating a safety message indicating the state of a sensor. A digital signature is then generated to sign this safety message. The method further includes communicating the safety message and the digital signature to an actuator. Upon receipt, the safety message is authenticated using the digital signature. A watchdog timer ensures transition to a safe state if authenticated messages are not received periodically.

Abstract: A system and method for generating instantaneous safety availability information relating to an instrumented function is described. In one embodiment, a time of a test performed on an instrumented function component of the instrumented function is received, and an elapsed time between the time of the test and a particular time is determined. And based upon the elapsed time, the instantaneous safety availability information for the instrumented function is calculated.

Abstract: A system and method for continuous online safety and reliability monitoring is disclosed. The method includes the steps of obtaining operating information about at least one of a plurality of instrumented function components, which are part of an instrumented function, and determining a probability of failure on demand for the instrumented function based on the operating information. In variations, operating information includes status information, which may be received from and/or provided to an asset management application. In some variations, instantaneous probability of failure on demand, online mean time to failure (MTTF), and online safety integrity level (SIL) are also calculated for an instrumented function. In yet further variations, the system allows a user to predict probability of failure on demand values into the future based on hypothetical and/or future planned test times.

Abstract: A system and method for continuous online safety and reliability monitoring is disclosed. The method includes the steps of obtaining operating information about at least one of a plurality of instrumented function components, which are part of an instrumented function, and determining a probability of failure on demand for the instrumented function based on the operating information. In variations, instantaneous probability of failure on demand, online mean time to failure (MTTF), and online safety integrity level (SIL) are also calculated for an instrumented function. In other variations of the invention, alarms are reported to an operator based on the variance indicating the probability of failure on demand for the instrumented function is too high. In yet further variations, the system allows a user to predict probability of failure on demand values into the future based on hypothetical and/or future planned test times.

Abstract: A system and method for fail-safe transmission of safety messages through communication channels containing non-safety-certified equipment is disclosed herein. Consistent with the disclosed method, digital signatures and/or encryption are used to authenticate both the origin and content of the safety messages. A watchdog timer ensures transition to a safe state if authenticated messages are not received periodically. In a particular implementation, the disclosed method includes generating a safety message indicating the state of a sensor. A digital signature is then generated to sign this safety message. The method further includes communicating the safety message and the digital signature to an actuator. Upon receipt, the safety message is authenticated using the digital signature. A watchdog timer ensures transition to a safe state if authenticated messages are not received periodically.

Abstract: A lift shaft which includes a plurality of self-supporting, prefabricated shaft modules which can be stacked. The lift shaft is constructed from one or more generally "plain" modules; a module containing a fully assembled lift car, optionally containing a counterweight which is temporarily supported for transit to the erection on-site; a fully assembled upper lift motor room module, including winding apparatus and electronic equipment for the lift; and a pit module which is to be suspended from a module above. The lift shaft and modules are designed so that they can be used as containers for fully assembled lift cars and/or counterweights between the factory and the building site so that a lift shaft module can be craned into position with a complete car and/or counterweight.