Abstract: A system with multiple processing domains sharing a memory resource accessed via a shared memory controller detects a memory error. As data is written to the shared memory resource, each processing domain generates a diagnostic code as a function of the data, the memory address for the data, and of a unique identifier corresponding to the processing domain. The diagnostic code is stored with the data for verification when the data is read back. As the data is read back, the processing domain separates the diagnostic code from the data being read and generates another diagnostic code in the same manner as the original diagnostic code. The other diagnostic code is compared to the initial diagnostic code. If both diagnostic codes are the same, the processing domain can be confident that the data read from the shared memory resource is the same as the data that was originally written.

Abstract: A system with multiple processing domains sharing a memory resource accessed via a shared memory controller detects a memory error. As data is written to the shared memory resource, each processing domain generates a diagnostic code as a function of the data, the memory address for the data, and of a unique identifier corresponding to the processing domain. The diagnostic code is stored with the data for verification when the data is read back. As the data is read back, the processing domain separates the diagnostic code from the data being read and generates another diagnostic code in the same manner as the original diagnostic code. The other diagnostic code is compared to the initial diagnostic code. If both diagnostic codes are the same, the processing domain can be confident that the data read from the shared memory resource is the same as the data that was originally written.

Abstract: A distributed modular input/output system includes a primary wireless device adapted to be operatively connected to an associated industrial controller. A secondary wireless device is physically disconnected from the primary wireless device. The secondary wireless device is operatively connected to the primary wireless device by a primary wireless backplane link. At least one input/output module is operatively connected the secondary wireless device. An associated field device can be connected to the at least one input/output module for communication with the associated industrial controller via the secondary wireless device, the primary wireless backplane link, and the primary wireless device. Typically, a plurality of the secondary wireless devices are physically disconnected from the primary wireless device and each includes one or more of the input/output modules operably connected thereto.

Abstract: A detector for magnetizable materials operates remotely to determine a amplitude and phase modification of an exciting magnetic field caused by the magnetizable materials. These amplitude and phase measurements are used to create a phase-amplitude trajectory in phase amplitude space, which may be finely divided to distinguish among a number of different types of components.

Abstract: A detector for magnetizable materials operates remotely to determine a amplitude and phase modification of an exciting magnetic field caused by the magnetizable materials. These amplitude and phase measurements are used to create a phase-amplitude trajectory in phase amplitude space, which may be finely divided to distinguish among a number of different types of components.

Abstract: A detector for magnetizable materials operates remotely to determine a amplitude and phase modification of an exciting magnetic field caused by the magnetizable materials. These amplitude and phase measurements are used to create a phase-amplitude trajectory in phase amplitude space, which may be finely divided to distinguish among a number of different types of components.

Abstract: A detector for magnetizable materials operates remotely to determine a amplitude and phase modification of an exciting magnetic field caused by the magnetizable materials. These amplitude and phase measurements are used to create a phase-amplitude trajectory in phase amplitude space, which may be finely divided to distinguish among a number of different types of components.

Abstract: A detector for magnetizable materials operates remotely to determine a amplitude and phase modification of an exciting magnetic field caused by the magnetizable materials. These amplitude and phase measurements are used to create a phase-amplitude trajectory in phase amplitude space, which may be finely divided to distinguish among a number of different types of components.

Abstract: A human/machine interface for designing, monitoring and troubleshooting complex industrial control systems uses the paradigm of the factory floor to organize machines, control program portions and data as virtual spatially linked objects that may be moved in three dimensions to be joined with other spatially linked objects. The user may move within the virtual factory floor among the spatially linked objects followed by spatially indifferent objects which provide tools for monitoring and interacting with the spatially linked objects. Proximity of visual objects determines data sharing between objects.

Abstract: Multiple bits of information may be conveyed by passive target material incorporating filaments of magnetizable material having different magnetization functions and, in particular, different coercivities. Detection of the presence or absence of the individual filaments may be done remotely by measuring induced flux B as a function of an externally imposed magnetic field waveform and subjecting the measured induced flux signal to differentiation or Fourier transform techniques.

Abstract: High data rate I/O modules may be placed on a synchronous bus used also with legacy low data rate I/O modules without rendering the latter modules incompatible and without changing the clock rate of the bus by interleaving extended data to be read at falling edges of the clock with conventional data for the legacy modules to be read at rising edges of the clock. High data rate modules read both extended and conventional data effectively doubling the data transmission rate.

Abstract: Wireless integrated miniature sensing stations which can be organized into a communicating network allow sensitive detection and analysis of vibration, infrared radiation, sound, or other physical signals indicative of an intruder or condition to be monitored over a wide area. The sensing stations operate on low power and include a sensor or sensors, a digital signal processor, a microprocessor, and a wireless transceiver for communication. Network communication is facilitated by multiple relayed transmissions from station to station.

Abstract: A digital communication network carries high and low priority data. The network stations that produce high priority data are assigned to a first group of stations and stations that produce low priority data are assigned to a second group with the two group not being mutually exclusive. Activity on the network is divided into periodic intervals of the same duration. Network control information, that defines how access to the medium, is determined is broadcast to all stations during a first segment of a periodic interval. The network control information defines the length of the periodic interval and of the periodic interval segments, and defines how many stations are in each group. Then during a second segment of the periodic interval, every station in the first group is afforded an opportunity, in a predefined order, to transmit high priority data over the medium.

Abstract: Activity on a digital communication network is divided into periodic intervals and during a segment of each periodic interval a moderator station broadcasts a numerical count of the periodic intervals to all stations on the network. Each station has a memory in which a numerical value is stored, and a comparator that compares the numerical value to the numerical count received from the network. When the numerical count of the periodic intervals equals the numerical value, an apparatus within the station performs a defined operation, such as transmitting a message over the network or synchronizing a clock in the station to a master time standard. The equality of the periodic interval count and the numerical value also can be used to determine when to signal an external device. By using the count of the periodic intervals in this manner, the operation of several stations on the network can be coordinated.

Abstract: A node circuit is operative to couple Manchester encoded data between a transmission medium and an associated electrical device. A first mechanism detects a message frame preamble having a pattern of alternating signal level of substantially identical duration, and a second mechanism that detects a start delimiter in the message frame. The start delimiter has a plurality of binary signal levels in a unique pattern that satisfies a defined set of criteria to optimize the probability that the pattern will be detected while minimizing the likelihood that random valid data will alias into the start delimiter pattern. A data decoder is provided to convert the Manchester encoded data into binary data which then is sent via a signal path to the associated electrical device. Another mechanism is included to detect a unique end delimiter that signals the termination of the message frame.

Abstract: A moderator on a communication network periodically transmits a set of parameters for a protocol that is used to communicate over the network. Each node on the network compares the set of protocol parameters from the moderator to a set of parameters stored in that node. If the sets of parameters at a given node do not match, that given node ceases transmitting messages over the network until either the set of protocol parameters from the moderator match the stored set of parameters, or a matching set of parameters is stored in the node. Typically the active node that is assigned the lowest numerical network address functions as the moderator. However, an automatic process is utilized to prevent a node with a non-matching set of the protocol parameters from becoming the moderator for more than a brief period of time. An override procedure is provided to force all the nodes on the network to adopt a common set of protocol parameters in the event that the automatic process fails.

Abstract: A communications interface circuit couples a host processor to a pair of serial communications links, During power-up the interface circuit negotiates a set of operating parameters with the host processor through a shared memory to establish the optimal conditions under which message data is to be exchanged between the serial communications links and the host processor.

Abstract: Each message carried by a communication network has a packet that contains data, a tag, and a generation count wherein duplicate packets sent in different messages have identical generation counts. A station includes a modem that connects to the communication network in order to receive messages. A fixed screener circuit has a first memory that stores a set of tag values and a fixed screener determines when a packet tag matches a tag value in the first memory. The station also has an interface through which tag values are received from an external device, such as a host computer. A general purpose screener includes a second memory with a plurality of storage locations in which to store tag values from the interface and a generation count associated with each tag value.

Abstract: A communications interface circuit couples a host processor to a pair of serial communications links. A shared memory is employed to pass message data and network management data between the host and the interface circuit, and each can interrupt the other through interrupt control lines. The shared memory stores a handshake segment that includes interrupt flags and acknowledge flags which enable a large number of different interrupt events to be efficiently serviced.

Abstract: A communications network is comprised of two or more stations which share mastership of the network by passing a token between them. While a station holds the token it may send low or high priority messages. It may also inform other stations of its intent to exit the network and it may solicit for new stations wanting to enter the network. The token is passed from station-to-station in accordance with a predetermined time schedule which insures each station fair access to the network while insuring that messages are conveyed between stations within a predetermined worst case time delay.