Fisher Controls International LLC

Adam Joseph Wittkop

Stephen George Seberger

Jimmie Lee Snowbarger

Bruce Frederick Grumstrup

Lorin Dion Miller

Marwan Brama

Chris Arnold

Davin Nicholas

Gregory R Bulleit

Bruce F Grumstrup

Process control instruments having local intrinsic safety barriers and methods of manufacturing the same are disclosed. An example field instrument for a process control assembly includes a non-protection compartment, intrinsically safe circuitry positioned in the non-protection compartment, a protection compartment, non-intrinsically safe circuitry positioned in the protection compartment, and local barrier circuitry positioned in the protection compartment to operatively couple the non-intrinsically safe circuitry to the intrinsically safe circuitry, the local barrier circuitry to prevent the intrinsically safe circuitry from receiving an electrical energy that is greater than an electrical energy threshold from the non-intrinsically safe circuitry.

Process control instruments having local intrinsic safety barriers and methods of manufacturing the same

Example methods and apparatus to correct remote sensor signals are disclosed. An example apparatus includes a sensor to generate a signal and a first memory to store calibration data associated with the sensor. The example apparatus also includes a second memory to store the calibration data and a first processor proximate to the sensor and the first memory to retrieve the calibration data from the first memory. In addition, the example apparatus includes a second processor, proximate to the second memory and remotely situated relative to the first processor. The second processor is to receive the signal from the sensor, receive the calibration data from first processor, and correct the signal based on the calibration data.

Methods and apparatus to correct remote sensor signals

A method of limiting control pressure provided to an actuator of a valve coupled to a valve positioner, a drive signal is provided to a pneumatic stage of the valve positioner. The pneumatic stage is arranged to control output pressure of the valve positioner in accordance with the drive signal. A pressure measurement from a pressure sensor communicatively coupled to the valve positioner is obtained, and an abnormal pressure is detected based on the pressure measurement. In response to detecting the abnormal pressure, the drive signal is controlled so as to limit the output pressure of the valve positioner, wherein the output pressure provides control pressure to the actuator.

Valve positioner with overpressure protection capabilities

Shielding performance and protection from radiated RF energy at a cable's point of entry to an enclosure are improved when a shield of the cable is AC coupled around an entire opening of the enclosure using a discoidal capacitor. The capacitor may be electrically coupled to the shield and the enclosure around the entire inner and outer circumferences of the discoidal capacitor. Compared to traditional DC coupling or the use of a drain wire and traditional capacitor, using the discoidal capacitor lowers inductance and improves shielding of the opening itself while improving AC filtering characteristics and preventing ground loops.

Capacitor coupled cable shield feedthrough

A bidirectional DC to DC converter having a first operational mode and a second operational mode includes a first terminal pair that has a positive terminal and a negative terminal and that connects the converter to a first electric circuit, a second terminal pair that has a positive terminal and a negative terminal and that connects the converter to a second electric circuit, an accumulation element for temporary accumulation of electric energy; and a switching circuit connected to the first terminal pair, the second terminal pair, and the accumulation element. Electric energy is transferred from the first electric circuit to the second electric circuit via the accumulation element in the first operational mode of the bidirectional DC to DC converter and, from the second electric circuit to the first electric circuit via the accumulation element in the second operational mode of the DC to DC converter.

Bidirectional DC to DC converter for power storage control in a power scavenging application

A method of scavenging power in a circuit having a power source generating electric current includes connecting a power scavenging device having an input terminal pair and an output terminal pair to the circuit via the input terminal pair, dynamically regulating a voltage drop across the input terminal pair of the power scavenging device, harvesting electrical energy available at the regulated voltage drop from the electric current flowing through the first input terminal pair of the power scavenging device, and providing the harvested electrical energy at the output terminal pair of the power scavenging device.

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Marshalltown, IA, United States of America

Adam Joseph Wittkop