1
Harry A Burns, Brent H Larson, Larry K Brown: Local device and process diagnostics in a process control network having distributed control functions. Fisher Controls International, Marshall O Toole Gerstein Murray & Borun, February 15, 2000: US06026352 (175 worldwide citation)

A field device for use in a process control network having a plurality of devices communicatively coupled by a two-wire, all-digital communication bus includes a connector that connects the field device to the two-wire, all-digital bus to enable all-digital communication over the bus, a memory that ...


2
Harry A Burns, Brent H Larson, Larry K Brown: Local device and process diagnostics in a process control network having distributed control functions. Fisher Controls International, Marshall O Toole Gerstein Murray & Borun, October 19, 1999: US05970430 (162 worldwide citation)

A field device for use in a process control network having a plurality of devices communicatively coupled by a two-wire, all-digital communication bus includes a connector that connects the field device to the two-wire, all-digital bus to enable all-digital communication over the bus, a memory that ...


3
William V Fitzgerald: Diagnostic apparatus and method for fluid control valves. Fisher Controls International, Marshall O Toole Gerstein Murray & Bicknell, March 30, 1993: US05197328 (154 worldwide citation)

Apparatus and method for diagnostically testing and determining the operating condition of a pneumatically operated valve. A diagnostic controller is connected to a valve actuator assembly so that diaphragm pressure and valve plug movement among other inputs can be sensed while the valve actuator as ...


4
Brent H Larson, Harry A Burns, Larry K Brown: Remote diagnostics in a process control network having distributed control functions. Fisher Controls International, Marshall O Toole Gerstein Murray & Borun, January 11, 2000: US06014612 (121 worldwide citation)

A diagnostic system is adapted to perform device and process diagnostics in a process control network having a plurality of process control devices communicatively linked over a bus, wherein each of the devices is capable of preforming a process control function and of communicating over the bus usi ...


5
Harry A Burns, Brent H Larson, Larry K Brown: Process control network with redundant field devices and buses. Fisher Controls International, Marshall O Toole Gerstein Murray & Borun, April 4, 2000: US06047222 (121 worldwide citation)

Functional elements within a two-wire, loop-powered, two-way digital communications environment are interconnected using selective redundant connections and selective redundant functional elements. The redundant functional elements and redundant connections provide a smooth transition from operation ...


6
Larry K Brown, Harry A Burns, Brent H Larson: Network accessible interface for a process control network. Fisher Controls International, Marshall O&apos Toole Gerstein Murray & Borun, February 20, 2001: US06192281 (113 worldwide citation)

An interface between a remote communications network and a process control system includes a storage device, a communication software stack and a user software layer. The user software layer enables interfacing between the remote communications network and the process control system by directing the ...


7
Stephen G Seberger, Bruce F Grumstrup, George W Gassman: Communication system and method. Fisher Controls International, Marshall O Toole Gerstein Murray & Borun, September 19, 1995: US05451923 (102 worldwide citation)

The present invention relates to a circuit which is connected by two-conductors to a control system for a variable analog DC input and that also enables bidirectional digital communication along the two conductors for diagnostic operations of an instrument. The novel circuit includes a switch circui ...


8
Stephen G Seberger: Interface apparatus for two-wire communication in process control loops. Fisher Controls International, Marshall O Toole Gerstein Murray & Borun, July 18, 1995: US05434774 (102 worldwide citation)

A process control system includes a process controller that develops a controller output signal having at least a desired DC component and an undesired AC component and a device having an adjustable parameter. An interface apparatus is coupled to the process controller and to the device via a two-wi ...


9
Larry K Brown, Brent H Larson, Harry A Burns: Maintenance interface device for a use in a process control network. Fisher Controls International, Marshall O&apos Toole Gerstein Murray & Borun, April 23, 2002: US06377859 (93 worldwide citation)

A maintenance interface device for use in a digital, loop-powered process control network includes an interface to either a two-wire input/output port of a field device or to a two-wire communication media, a control logic for determining a simple status of the field device or communication loop, an ...


10
Paul R Adams, Karl J Gabel, Daniel G Roper: Intelligent pressure regulator. Fisher Controls International, May 2, 2000: US06056008 (77 worldwide citation)

An intelligent pressure regulator for maintaining a fluid in a process at a predetermined pressure includes an electronic controller which enhances regulator performance and provides self-diagnostics and communications capabilities. The electronic controller includes a pressure sensor which provides ...