公开(公告)号：DE10196024T1

公开(公告)日：2003-03-13

申请号：DE10196024

申请日：2001-03-21

Applicant: ROSEMOUNT INC

Inventor： LOVEGREN ERIC R ,  PEDERSON DAVID L

IPC: G01F23/284 ,  G01N22/00 ,  G01S7/292 ,  G01S15/00

公开(公告)号：GB2355878A

公开(公告)日：2001-05-02

申请号：GB0023692

申请日：2000-09-27

Applicant: ROSEMOUNT INC

Inventor： DIEDE KURT C ,  LOVEGREN ERIC R

IPC: G01F23/284 ,  G01F25/00 ,  G01S13/88

Abstract: A microwave radar instrument using time-domain reflectometry (TDR) to measure the level of a product 14 in a container 12 comprises a probe 110 having a reference impedance discontinuity 155, extendable into a product through an interface 127. A transceiver 140 is adapted to transmit a microwave pulse along the probe, a first portion being reflected at the reference impedance discontinuity 155 and forming a first reflected wave pulse, and a second portion being reflected at the product interface 127, forming a second reflected wave pulse. A processor 130, coupled to the transceiver, is adapted to provide a level output signal indicative of the product height or depth based on the time of detection of the reflected second portion, and a diagnostic signal which may be indicative of the operating state of the probe, as a function of the reflected first portion amplitude in comparison with upper or lower limit values (e.g. 166,168 in Figure 3A). For instance, a diagnostic signal above an upper limit 166 (Fig 3B) may indicate a submerged termination (a full tank), and a signal below lower limit 168 (e.g. Fig 3C) may indicate a broken connection between the probe 110 and transceiver 140.