Abstract: A computer network system repetitively distributes messages including uniquely identified blocks of real time data containing a current data image over a broadcast communications network to all real time stations for storage of each repetition of each entire block of data directly in station memory at a unique address space assigned to that uniquely identified block of data. The real time stations receive the blocks of data and alternatively receive other messages from the real time stations. The other messages have a recognized standard protocol, such as the TCP/IP or UDP/IP protocol of the Internet Protocol Suite.

Abstract: Updated images of messages are passed between asynchronous digital processors using dual port shared memory. In the basic form of the invention, three buffers in shared memory are assigned to each message. Where one of the processors is a controller for a data link channel carrying n messages, 2n+1 buffers are provided in free shared memory space with 2 buffers assigned to each message at all times and a common buffer serving as the third buffer for all of the messages. Where linked buffers in local memory of a controller processor receive message updates from a data highway, two buffers in shared memory are assigned to each message and a linked buffer in the controller local memory serves as the third buffer. The buffers containing the message updates are passed between processors by use of a buffer status array in shared memory. A semaphore lock in the array permits only one processor at a time to assign or release buffers.

Abstract: Signals from redundant sensors located throughout a pressurized water reactor (PWR) nuclear power plant are processed in four independent channel sets each of which includes a plurality of independent microcomputers which calibrate, convert to engineering units and calculate partial trip signals and engineered safeguard actuation signals from the sensor signals for use in the conventional voting logic of a plant protection system. The primary and secondary partial trip and engineered safeguard actuation functions associated with various postulated abnormal events are allocated to different independent microcomputers in the channel set for reliability. A test unit common to the channel set automatically, rapidly bypasses and tests each protection function independently while the other protection functions in the channel set remain on-line and also continually tests each microcomputer through a dummy test function performed along with the assigned protection functions.

Abstract: A signal processor which applies non-linear dynamic compensation to an applied analog signal is tested by applying to a reference ramp signal compensation having a transfer function equal to the inverse of the transfer function of the signal processor. This test signal is applied to the signal processor in place of the sensor signal so that after the compensation of the processor is applied to it, the resultant signal should match the reference signal. When the signal processing is carried out digitally in a microcomputer and the response to the test signal is multiplexed back to the tester along with response signals from other microcomputers, variable time skewing of the returned test signal is eliminated by feeding the reference signal through a processing path parallel to that of the test signal and then comparing those two signals in the tester.

Abstract: A nuclear reactor flux mapping system having a plurality of neutron detectors operable to be driven into and out of a reactor core along any one of a number of pre-established paths. The detectors, corresponding drives (22) and drive controllers (28) are arranged into at least two physically separate and functionally independent channels. Each channel is respectively arranged to scan complementary paths through the core during normal system operation. At least two, redundant, functionally independent and physically separate "command end of processing" channels (31 and 33) are provided. Each of the command and processing channels (30) are independently operable to automatically, programmably sequence the detector scans and process the detector output data on all of the detector channels while being electrically buffered from each detector channel through two-ported memories (36) in a manner to prevent faults on any of the channels from disabling any of the other system channels.