Invensys Systems, Inc.

The Foxboro Company

Schneider Electric Systems USA, Inc.

William M Slechta

Simon Korowitz

Nathan H Tobol

M Charles Cheney

Providing a fast response to a process step while allowing a sensor response to remain relatively slow. A mechanical component generates a response to a step change in a physical property and an electrical component generates an analog electrical signal indicative of the response generated by the mechanical component over a period of time. The analog electrical signal is converted into digital values and the digital values are used to indicate the final value of the step change in the physical property before the period of time has elapsed.

Inferential sensing engine

A slew rate detection circuit connected to a sensor detects when an analog electrical signal from the sensor indicates a slew rate that exceeds a threshold value, and generates an interrupt electrical signal when the slew rate is detected as exceeding the threshold value. A control circuit determines a measurement value of the physical property in response to receiving the interrupt signal. The control circuit is connected to an A/D converter, which converts the analog electrical signal into a digital electrical signal, and performs a plurality of sensing system operations including determining the measurement value of the physical property as a function of the digital electrical signal.

Slew rate detection circuit

A sensing system comprising a sensor for generating an analog electrical signal indicative of a sensed physical property and an A/D converter for converting the analog electrical signal into a digital electrical signal. A control circuit connected to the A/D converter is configured to receive the digital electrical signal and to perform a plurality of sensing system operations including determining a measurement value of the physical property as a function of said received digital electrical signal. A slew rate detection circuit connected to the sensor is configured to detect when the analog electrical signal indicates a slew rate that exceeds a threshold value, and to generate an interrupt electrical signal when the slew rate is detected as exceeding the threshold value. The control circuit determines a measurement value of the physical property in response to receiving the interrupt signal.

According to the principles of the invention, there is provided a system that identifies spurious noise values in an input signal and replaces them with substitute values representative of the spurious-noise-free signal. The system is activated when the signal deviation exceeds a predetermined threshold, otherwise passing the signal unchanged. The substituted representative values are determined based on historical signal data, preferably a moving average with a fixed window. There is further provided a maximum glitch width which prevents inadvertent suppression of a true step in the input signal, and a relaxation time which prevents consecutive filter activations from unduly masking the input signal.

Spurious noise filter

A method for transmitting messages between a communications controller and devices in a factory process control system, wherein each device has an associated identification number which is unique to that device. A message to be transmitted is compiled, and then based on the criticality of the message, one of a standard, secure, or critical message protocols is chosen for the message; each protocol being defined to generate a message checksum for the message in a manner different from the other protocols. The generated checksum is then included in the message. Using the secure and critical protocols, a message checksum is generated from the message to be transmitted and the identification number of the intended recipient device. In the secure protocol, the message checksum is included in the message, but the identification number is not included in the message; in the critical protocol, both the message checksum and the identification number are included in the message. A crosstalk query message may be sent from the controller to determine if a link of a factory process control system is susceptible to crosstalk. The controller sends to a link on which a particular device is known to reside a diagnostic message indicating the identification number of the particular device and requesting any other devices that unintentionally receive the message to transmit a response message to the communications controller.

Growing community of inventors

North Attleboro, MA, United States of America

William M Slechta