Rosemount Inc.

Rosemont Inc.

David L Pederson

Richard Louis Nelson

Randy J Longsdorf

John Allan Kielb

Eric R Lovegren

Grant Bradley Edwards

A method for detecting the presence of a twin peak pulse in a waveform, generated by a microwave level transmitter, that is used to detect levels of first and second material interfaces relating to materials contained in a tank. The waveform develops a twin peak pulse when the first and second material interfaces are in close proximity to one another. The twin peak pulse contains overlapping first and second received wave pulses reflected from the first and second material interfaces, respectively. The method determines that the waveform contains a twin peak pulse when both a first peak point relating to the first received wave pulse and a valley are detected. A microwave level transmitter having an interface detection module that is configured to use the method of the present invention to detect the existence of a twin peak pulse in a waveform.

Close proximity material interface detection for a microwave level transmitter

A process transmitter communications circuit has link terminals which are coupled to a process link, which supplies power to the circuit. A power source is coupled to one of the link terminals and is independent from the power supplied from the process link. Communications circuitry is coupled to the power source and link terminals, which transmits a transmitter signal over the process link, through the link terminals. A power sensing component is coupled to at least one of the link terminals and the communications circuitry and senses whether the power supplied by the process link is inadequate to transmit the transmitter signal. A power control component is coupled to the power source, the link terminals and the communications circuitry and selectively applies power from the power source to the communications circuitry for transmitting the transmitter signal when the power sensing component senses there is inadequate power supplied by the process link.

Process transmitter communication circuit

An apparatus receives a query from a process controller containing a process variable address representing a storage location for a process variable in a network of field devices. A communication standard type and an unique field device address is associated with each field device. An associating section identifies a field device address and a communication standard type associated with each of a plurality of process variable addresses. An extracting section matches the stored process variable address with a process variable address in the associating section and extracts the associated field device address and the associated communication standard type from the associating section. A generating section generates a field device request containing the extracted associated field device address as a function of the extracted associated communication standard type. The field device request is conveyable over a communication line to address the storage location represented by the stored process variable address.

Interface controller for matching a process address field from a

An existing analog two-wire transmitter has a sensor module, an analog excitation circuit, and an analog detector circuit which provides an output representative of a sensed process variable, such as pressure, to a two-wire current loop. The analog detection circuit is removed and replaced with apparatus including a digital converter that digitally calculates the transmitter's output. The output is improved by calculating correction for linearity. The analog excitation circuit may also be replaced with a replacement excitation circuit. The replacement excitation circuit and the digital converter can be energized in series to control energization current. A charge pump can be coupled to the loop to balance the current in the series circuit. The digital converter can also provide electrical span and zero adjustments.

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Hopkins, MN, United States of America

David L Pederson