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US 2005/0168343 A1Published application
Process control loop current verification
AssigneeRosemount Inc.
InventorsRandy Longsdorf, Garrie Huisenga, James Johnson
Life of this patent
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Abstract
A process device is configured for coupling to a two wire process control loop. Loop current output circuitry is configured to apply an output current to the two wire process control loop. Loop current verification circuitry is coupled to the two wire process control loop and configured to detect errors in the applied output current. At least a portion of the loop current verification circuitry is independent from the loop current output circuitry.
Claims22
A process device, comprising;
- loop current output circuitry configured to apply an output current to a two wire process control loop;
- and
- loop current verification circuitry coupled to the two wire process control loop to detect errors in the applied output current, wherein at least a portion of the loop current verification circuitry is independent from the loop current output circuitry.
A method in a process device for verifying loop current in a two wire process control loop, comprising:
- sensing a process variable;
- adjusting a loop current in the two wire process control loop as a function of the sense process variable;
- verifying a value of the current in two wire process control loop using at least one electrical component which is independent of electrical components used to set the loop current in the two wire process control loop.
Dependencies are inferred from the claim text.