Abstract: A method for broadcasting data on a peripheral component interconnect bus includes coupling at least one master agent, at least one responding target agent and at least one snooping target agent to the peripheral component interconnect bus, transmitting a standard PCI master agent signal from the master agent to the responding target agent, transmitting a standard PCI responding target agent signal, driven by the responding target agent, from the responding target agent to the master agent and monitoring the standard PCI master agent signal and the standard PCI responding target agent signal using the snooping target agent.

Abstract: The invention disclosed is useful in an I/O system of a programmable controller and provides a method and circuitry by which control and diagnostic information is exchanged between a control unit of an I/O module and a plurality of input/output points of the I/O module. A control signal is generated in the control unit in the form of sequential pulse frames such that the control information is defined by a series of pulse width modulated pulses. Each frame includes a no-pulse time period following the review of pulses to mark the end of a frame. Each I/O point receives a control signal of its own and generates a clock pulse in response to each pulse. The clock pulse initiates a sampling of the corresponding pulse and simultaneously initiates return of a diagnostic signal value to the central unit. Thus, the control signal provides for sampling of its own content and provides for a return of a diagnostic data bit for each control bit.

Abstract: A combined input/output circuit is provided which is configurable either as in input circuit or an output circuit for use in a programmable controller. The input/output circuit includes apparatus which detects undesired overcurrent and overvoltage external conditions and adaptively protects itself from such conditions. The circuit includes a sensing circuit which is capable of sensing overcurrent conditions and detecting input data depending on the configuration of the input/output circuit. The inherent characteristics of a switching device used to configure the circuit in either an input or output state are used to detect overcurrent and to limit fault current.

Abstract: The invention disclosed is useful in an I/O system of a programmable controller and provides a method and circuitry by which control and diagnostic information is exchanged between a control unit of an I/O module and a plurality of input/output points thereof. A control signal is generated in the control unit in the form of sequential pulse frames such that the control information is defined by a series of pulse width modulated pulses. Each frame includes a no-pulse time period following the review of pulses to mark the end of a frame. Each I/O point receives a control signal of its own and generates a clock pulse in response to each pulse. The clock pulse initiates a sampling of the corresponding pulse and simultaneously initiates return of a diagnostic signal value to the central unit. Thus, the control signal provides for sampling of its own content and provides for a return of a diagnostic data bit for each control bit.

Abstract: A method and apparatus by which the output value of a resolver position detection system is compensated for systematic phase shift errors produced by signal conditioning circuitry through which the signal passes.

Abstract: A drive circuit is responsive to input pulses to supply drive energy pulses to the printing head of a matrix printer so as to produce constant impact forces and constant print intensity over a wide range of print rates by decreasing the energy of the drive pulses as a function of the time interval between successive input pulses as said interval diminishes below a predetermined value. In one embodiment the amplitude of the drive pulses is reduced as the frequency of the input pulses exceeds the predetermined value. In a second embodiment the duration of the drive pulses is reduced as the frequency of the input pulses exceeds the predetermined value.