Adjustable process variable transmitter

Abstract

Abstract A process variable transmitter 2 senses a process variable, such as pressure 3, and produces an output current in the range 4 to 20 mA. The sensor 4 produces this range for an inbuilt pressure range 0 to URL (upper range limit), and is followed by adjustment means which are settable to produce the output current range for an input pressure range from LRV (lower range value) to URV (upper range value), which is obviously within the range 0 to URL. To avoid interaction between the settings of LRV and URV, the signal is converted into digital form at 6, processed by a microcomputer 8,14-19, and converted back to analog form at 10. The microcomputer stores the processing equation where LRV is set by generating an LRV set signal at 20 simultaneously with applying the LRV pressure, and then URV is set by generating a URV control signal at 22 simultaneously with applying the URV pressure.

Inventors

• 👤 Stephen J. Bayer
• 👤 Arthur M. Olsen

Bibliographic Details