Fisher Controls International LLC

Marwan Brama

Pei Li

Stephen George Seberger

Richard Jay Winkler

Adam Joseph Wittkop

Stanley Felix Amirthasamy

Chris Arnold

Davin Nicholas

Gregory R Bulleit

Richard J Winkler

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

The described methods and systems enable a control panel for a safety valve in a safety system of a process control environment to couple to a safety loop that couples a logic solver to a valve positioner for the safety valve. The control panel may drive a loop current on the safety loop to a desired range, thereby causing the valve positioner to respond by initiating a desired function triggered by the loop current entering the desired range. The desired function may be a trip function, a reset function, or a stroke test function.

Activating trip functions of a safety valve positioner by way of a control panel to achieve a safe state

The present disclosure provides a circuit comprising: a 4-20 mA transmitter; a transformer having a primary winding and a secondary winding; a first current-sense resistor connected in series with the primary winding and a current regulator, wherein the current-sense resistor is configured to measure a first voltage and provide the measured first voltage to the current regulator, the current regulator being configured to output a current proportional to the measured first voltage; and a second current-sense resistor connected in series with the secondary winding, wherein the current-sense resistor is configured to measure a second voltage such that a current associated with the 4-20 mA transmitter is determined based on the second voltage.

Method to provide analog voltage signal proportional to 4-20MA transmitter current using a DCDC converter across galvanic isolation of a transformer

An example visual indicator includes a base defining a light chamber and a first cover removably coupled to the base to cover the light chamber. A light assembly is positioned in the light chamber of the base. The light assembly has a first connector projecting from the base and the first connector is to pass through an access opening formed in an outer surface of a control panel when the visual indicator is coupled to the control panel. The base is to engage the outer surface of the control panel when the visual indicator is coupled to the control panel. The visual indicator is to enable an ingress protection rating of the control panel to be maintained when at least one of the visual indicator is removed from the control panel or the first cover of the visual indicator is replaced with a second cover different than the first cover.

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Singapore, Singapore

Marwan Brama