The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 1993
Filed:
Apr. 28, 1988
John A Kielb, Eden Prairie, MN (US);
Richard L Nelson, Eden Prairie, MN (US);
David L Pederson, Hopkins, MN (US);
Rosemount Inc., Eden Prairie, MN (US);
Abstract
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.