Abstract: A module health system includes a module health circuit comprising a hardware register that is set to a first value in response to the system starting, an application register that is set to the first value in response to the system starting and a watchdog timer register that is set to the first value in response to the system starting. The system further includes a power on self-test that determines whether the system has passed a plurality of tests and that selectively sets the hardware register to a second value based on the determination, an external software application that determines whether a safety critical system is healthy and selectively sets the application register based on the determination, a watchdog timer application that selectively sets the watchdog timer register, a central processing unit that determines whether to de-assert a module health signal.

Abstract: A system for synchronizing central processing units (CPU) includes a schedule module that communicates a synchronization point, a first CPU that writes a first memory address to a first register in response to the first CPU reaching the synchronization point, and a second CPU that writes a second memory address to a second register in response to the second CPU reaching the synchronization point. The system further includes a first logical AND module that writes a first value to a third register based on the first and second memory addresses and a second logical AND module that writes a second value to a fourth register based on the first and second memory addresses. The system also includes a scheduler module that selectively generates a processor sync signal based on the first and second value.

Abstract: A module health system includes a module health circuit comprising a hardware register that is set to a first value in response to the system starting, an application register that is set to the first value in response to the system starting and a watchdog timer register that is set to the first value in response to the system starting. The system further includes a power on self-test that determines whether the system has passed a plurality of tests and that selectively sets the hardware register to a second value based on the determination, an external software application that determines whether a safety critical system is healthy and selectively sets the application register based on the determination, a watchdog timer application that selectively sets the watchdog timer register, a central processing unit that determines whether to de-assert a module health signal.

Abstract: A dual redundant computer safety relay box system includes first and second fail-safe computing systems (FSCs) individually mounted to first and second printed circuit boards. Each FSC includes two computing modules (CPUs) designated as a first CPU and a second CPU. The first and second FSC's are both connected to a safety relay box. The printed circuit boards are isolable from each other permitting maintenance on one of the printed circuit boards while operation of the FSC of the other printed circuit board is maintained. In each FSC a health signal generated from the first and second printed circuit boards of the first and second CPUs defines a multi-level dynamic pulse signal. Presence of the dynamic pulse signal produces an output identified as each of a first and a second healthy indication signal from each of the CPUs of one of the first or second FSCs.

Abstract: A module health system includes a module health circuit comprising a hardware register that is set to a first value in response to the system starting, an application register that is set to the first value in response to the system starting and a watchdog timer register that is set to the first value in response to the system starting. The system further includes a power on self-test that determines whether the system has passed a plurality of tests and that selectively sets the hardware register to a second value based on the determination, an external software application that determines whether a safety critical system is healthy and selectively sets the application register based on the determination, a watchdog timer application that selectively sets the watchdog timer register, a central processing unit that determines whether to de-assert a module health signal.

Abstract: A system includes a safety relevant component that generates a data packet in response to receiving a request to perform a task and that communicates the data packet. The system further includes a first fail-safe chassis (FSC) that continuously generates a first chassis health signal, that determines whether the data packet is valid, and that selectively determines whether to de-assert the first chassis health signal based on the determination. The system also includes a second FSC that continuously generates a second chassis health signal, that determines whether a copy of the data packet is valid, and that selectively determines whether to de-assert the second chassis health signal based on the determination. The system further includes a safety relay box module that determines whether to instruct the first FSC to operate in a predetermined mode based on the first chassis health signal and the second chassis health signal.

Abstract: A fault-tolerant failsafe computer voting system includes a switch module that generates a first copy of a first data packet and a second copy of the first data packet and that communicates the first copy and the second copy. The system also includes a first voting module that generates a first packet signature based on the first copy and communicates the first packet signature. The system further includes a second voting module that generates a second packet signature based on the second copy and communicates the second packet signature.

Abstract: A system for synchronizing central processing units (CPU) includes a schedule module that communicates a synchronization point, a first CPU that writes a first memory address to a first register in response to the first CPU reaching the synchronization point, and a second CPU that writes a second memory address to a second register in response to the second CPU reaching the synchronization point. The system further includes a first logical AND module that writes a first value to a third register based on the first and second memory addresses and a second logical AND module that writes a second value to a fourth register based on the first and second memory addresses. The system also includes a scheduler module that selectively generates a processor sync signal based on the first and second value.

Abstract: A system for synchronizing central processing units (CPU) includes a schedule module that communicates a synchronization point, a first CPU that writes a first memory address to a first register in response to the first CPU reaching the synchronization point, and a second CPU that writes a second memory address to a second register in response to the second CPU reaching the synchronization point. The system further includes a first logical AND module that writes a first value to a third register based on the first and second memory addresses and a second logical AND module that writes a second value to a fourth register based on the first and second memory addresses. The system also includes a scheduler module that selectively generates a processor sync signal based on the first and second value.

Abstract: A fault-tolerant failsafe computer system including an inter-processor communication channel includes a transmission control module that encodes a first data packet and communicates a first encoded copy of the first data packet and a second encoded copy of the first data packet. The system also includes a receiver control module that i) receives a first encoded copy of a second data packet and a second encoded copy of the second data packet and ii) decodes the first encoded copy and the second encoded copy. The system further includes a de-duplication module that receives a plurality of data packets and communicates at least one unique data packet of the plurality of data packets.

Abstract: A system includes a first application that writes a first plurality of tasks to a first memory buffer; a second memory buffer that receives a copy of the first plurality of tasks; a second application that writes a second plurality of tasks to a third memory buffer; and a fourth memory buffer that receives a copy of the second plurality of tasks. The system further includes a first comparison module that generates a first voting signal based on a first comparison between a first task and a second task. The system further includes a second comparison module that generates a second voting signal based on a second comparison between the first task and the second task. The system further includes a first central processing unit (CPU) that selectively determines whether to de-assert a module health signal based on the first voting signal and the second voting signal.

Abstract: A system for synchronizing central processing units (CPU) includes a schedule module that communicates a synchronization point, a first CPU that writes a first memory address to a first register in response to the first CPU reaching the synchronization point, and a second CPU that writes a second memory address to a second register in response to the second CPU reaching the synchronization point. The system further includes a first logical AND module that writes a first value to a third register based on the first and second memory addresses and a second logical AND module that writes a second value to a fourth register based on the first and second memory addresses. The system also includes a scheduler module that selectively generates a processor sync signal based on the first and second value.

Abstract: A fault-tolerant failsafe computer system including an inter-processor communication channel includes a transmission control module that encodes a first data packet and communicates a first encoded copy of the first data packet and a second encoded copy of the first data packet. The system also includes a receiver control module that i) receives a first encoded copy of a second data packet and a second encoded copy of the second data packet and ii) decodes the first encoded copy and the second encoded copy. The system further includes a de-duplication module that receives a plurality of data packets and communicates at least one unique data packet of the plurality of data packets.

Abstract: A system includes a first application that writes a first plurality of tasks to a first memory buffer; a second memory buffer that receives a copy of the first plurality of tasks; a second application that writes a second plurality of tasks to a third memory buffer; and a fourth memory buffer that receives a copy of the second plurality of tasks. The system further includes a first comparison module that generates a first voting signal based on a first comparison between a first task and a second task. The system further includes a second comparison module that generates a second voting signal based on a second comparison between the first task and the second task. The system further includes a first central processing unit (CPU) that selectively determines whether to de-assert a module health signal based on the first voting signal and the second voting signal.

Abstract: A fault-tolerant failsafe computer voting system includes a switch module that generates a first copy of a first data packet and a second copy of the first data packet and that communicates the first copy and the second copy. The system also includes a first voting module that generates a first packet signature based on the first copy and communicates the first packet signature. The system further includes a second voting module that generates a second packet signature based on the second copy and communicates the second packet signature.

Abstract: A module health system includes a module health circuit comprising a hardware register that is set to a first value in response to the system starting, an application register that is set to the first value in response to the system starting and a watchdog timer register that is set to the first value in response to the system starting. The system further includes a power on self-test that determines whether the system has passed a plurality of tests and that selectively sets the hardware register to a second value based on the determination, an external software application that determines whether a safety critical system is healthy and selectively sets the application register based on the determination, a watchdog timer application that selectively sets the watchdog timer register, a central processing unit that determines whether to de-assert a module health signal.