General Electric Company

Ge Fanuc Automation North America, Inc.

Joseph J Cieri

Ronald E Gareis

Kenneth M Holet

Mark J Kocher

Michael J Tuso

Michael W Smith

Ancil B Cruickshank

Timothy P Near

A Alan Tuten

An input/output (I/O) port designed for electrical interconnection with multiple similar ports includes an input read circuit, an output drive circuit, and a circuit to control the port for input or output mode by electrically disconnecting the output drive circuit from the port. Also included is a back drive current protection circuit placed in series in between an external I/O line and the input read and output drive circuits which blocks backdrive currents from other active processors when the processor that includes the protection circuit is in a powered down state while still allowing full input/output functionality in a powered up state.

Methods and apparatus for full I/O functionality and blocking of backdrive current

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.

Programmable controller input/output communications system

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.

A method of determining access on an electronic serial bus by implicit token passing. The serial bus receives and transmits data between a plurality of devices. Each device has a receiver for receiving data to the serial bus, a transmitter for transmitting data to the serial bus, a bus idle timer for detecting an idle condition on the bus, and a bus access timer for controlling access to the serial bus. Each device is assigned a unique bus address. The bus access timer of each device is loaded with a value representative of each device's own unique bus address and the unique bus address of the transmitting device. The bus access timer starts a count upon receiving an end of transmission condition from the transmitting device and stops upon receiving a start of transmission condition from the transmitting device. When a bus access timer of a device reaches a predetermined value, the device of the timed out bus access timer is given access to the bus.

Growing community of inventors

Graves Mill, VA, United States of America

Joseph J Cieri