Rockwell Automation, Inc.

Ics Triplex Technology Limited

Rockwell Automation Technologies Incorporated

Thomas Bruce Meagher

Gerald Robert Creech

Kenneth John Murphy

Linda Murphy, Legal Representative

Philip John Agar

Shelby Adam Murrell

Ian Jones

Ian David D W Jones

Ian D W Jones

Robert Sidney Ord

Ian David Wynne Jones

Gerry Creech

An output module comprises two management units each of which calculates the current demand for the module independently from one another. One management unit controls an output current, controller whilst the other unit monitors the current produced by the output current controller against an independently calculated demand. The output module has multiple output modules. In normal operation, each module provides a portion of the required output current, the total output current being equal to the sum of the currents output by each module. in the event of failure on one of the, modules, the other module or modules switch to providing the total current required and the failed module is switched to a fail safe mode by using an isolation circuit to switch off the output current from that module.

Method and apparatus for analogue output current control

This invention relates to input channel diagnostics for an industrial process control system. The invention provides improved apparatus and methods relating to fault containment, overload protection and input channel diagnostics.

Input channel diagnostics

This invention relates to an apparatus and method for output current control in an Industrial Process Control System, The output module comprises two management units each of which calculates the current demand for the module independently from one another. One management unit controls an output current controller whilst the other unit monitors the current produced by the output current controller against an independently calculated demand. The output module has multiple output modules. However rather than one module providing a backup for the other modules, or alternating between use of each module, in normal operation, each module provides a portion of the required output current, the total output current being equal to the sum of the currents output by each module. In the event of failure on one of the modules, the other module or modules switch to providing the total current required.

An output module for an Industrial Process Control System that drives a load in a failsafe manner. The output module drives a load in response to a driving signal and includes a controller that generates a command signal and a drive enable signal in response to said driving signal. A keep alive circuit generates an active keep alive signal unless the drive enable signal is inactive. The output module includes a driver circuit that generates a drive signal in accordance with the command signal when the keep alive signal is active such that the load can be driven with a channel failsafe switch in response to the drive signal. The output module can be integrated into any of a number of industrial process control systems to enhance the operability of such systems.

Method and apparatus for driving a load

A system for protecting against reverse current flow in an output module of an Industrial Process Control System includes a transistor that is driven by a control signal and a current monitor arranged to monitor a current through the transistor. The system includes a processor that is arranged to receive the monitored current and to generate the control signal in dependence upon the monitored current. The processor is configured to turn off the transistor if a reverse current is detected in the transistor. Extension of the system provides a power feed combiner that is protected against reverse current flow.

Method and apparatus for protecting against reverse current flow

Input channel diagnostics for an industrial process control system that provides improved apparatus and methods relating to fault containment, overload protection and input channel diagnostics. The input circuit includes one or more series resistors that have a total resistance that is at least two orders of magnitude greater than the magnitude of the resistance of a conditioned sensor signal source.

This invention relates to fault detection in electrical circuits, in particular it relates to fault detection for a plurality of adjacent input circuits. The invention provides a method and apparatus for detecting a control or communication fault on an analogue circuit by simulating said analogue circuit using a simulated circuit comprising digital circuit components; the simulated circuit receiving a control input to provide a first output; and the analogue circuit receiving said control input to provide a second output; and setting an error condition when the first output and the second output differ.

Fault detection method and apparatus for analog to digital converter circuits

A power supply that is capable of supplying power to an input/output channel for an Industrial Process Control System. The power supply includes a primary voltage converter having a first voltage input and a second voltage output, and overvoltage protection components that prevent the second voltage from rising above a predetermined maximum. The power supply includes a first low dropout regulator that is connected to receive the second voltage and to generate a third voltage, a second low dropout regulator that is connected to receive the second voltage and to generate a fourth voltage, and a third low dropout regulator that is connected to receive the fourth voltage and to generate a fifth voltage. The power supply provides an over-voltage fault tolerant self-testable architecture, allows for compact low cost individual channel isolation and fault tolerant EMI/RFI filtration.

Method and apparatus for power supply

A method and system for testing and protecting the operability of an output module. An output channel includes a transistor having a gate, a source, and a drain. The output channel drives a load with a load voltage and a load current in dependence upon a gate drive signal applied to the gate. The system determines a voltage threshold and a current threshold and monotonically varies the gate drive signal from a starting value for a predetermined time interval while monitoring the load current and the load voltage. The system returns the gate drive signal to the starting value if any of the load voltage reaches the voltage threshold, the load current reaches the current threshold, or a predetermined time interval expires indicating the condition of the output module.

Method and apparatus for testing and protecting digital output circuits

An industrial process control apparatus and method that includes a number of processors and a number of input/output modules. Each processor is connected to a plurality of the input/output modules by a unidirectional command line. Each input/output module is connected to a plurality of the processors by a unidirectional response line. The processors are arranged to issue an identifier request to all of the connected input/output modules and each input/output module is arranged to respond to the identifier request via the respective response line with a response that includes a unique identifier. Such a configuration allows each processor to identify the physical location of each respective input/output module.

Method and apparatus for interconnecting modules

This invention relates to line frequency synchronisation for use in diagnostics for alternating current electrical circuits. The invention provides a method of synchronising measurement system frequency with an alternating current line frequency comprising the steps of: adjusting the frequency of the measurement system frequency using a frequency locked loop until the measurement system frequency is within a predetermined range of said alternating current line frequency; and when the measurement system frequency is within a predetermined range of said alternating current line frequency adjusting the phase and the frequency of the measurement system frequency using a phase and frequency locked loop.

Line frequency synchronization

This invention relates to fault detection in electrical circuits. The invention provides a switch for a fault tolerant digital output module comprising: an output transistor pair for enabling and disabling an alternating output current; and a current limiter for clamping the output current to a predetermined maximum value.

Overload protection method

This invention relates to overload protection for a circuit driving a direct current (DC) load. The invention provides a method of generating an overload condition for an output module driving a load having a load current and a load voltage comprising the steps of: monitoring the load current at sample intervals; comparing the monitored load current to a predetermined load current threshold; starting an overload timer in the event that the timer is not running and the monitored load current is greater than said load current threshold; monitoring the load voltage at said sample intervals; generating a ramped load voltage waveform for reference purposes in dependence upon an initial load voltage and a predetermined step size load voltage in the event that the overload timer is running; generating an overload condition in the event that the monitored load voltage is less than said ramped load voltage reference waveform, the ramped load voltage is less than a predetermined positive ramp limit and the overload timer is running.

This invention relates to fault detection in electrical circuits. The invention provides a method and apparatus for testing an input circuit by generating a periodic test signal having a predetermined phase and a predetermined amplitude; summing the test signal and an input signal to provide a summed signal; processing the summed signal to provide an output signal; generating an extracted test signal from the output signal; comparing the extracted test signal with a reference signal representing said periodic test signal; generating an error signal in dependence upon the result of said comparing step. The invention also provides a method and apparatus for testing a plurality of adjacent input circuits.

Fault detection method and apparatus

This invention relates to a method and apparatus for output current control. The invention provides an output module slice for controlling an output current comprising: an output field interface controller for controlling an input voltage to a first field effect transistor; an analogue to digital converter connected to read the current flowing through said first field effect transistor and to provide a digital signal dependent thereon to said output field interface controller.

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Houston, TX, United States of America

Thomas Bruce Meagher