07-02-2013, 02:48 PM
Study of Level Transmitter
STUDY OF AC TO DC CONVERTER.pptx (Size: 235.02 KB / Downloads: 44)
Level Transmitter
Level Transmitter detect the Level of substances that flow,including liquids,granular materials, and powders. Fluids and fluidized solids flow to become essentially level in their containers (or other physical boundaries) because of gravity whereas most bulk solids pile at an angle of repose to a peak. The substance to be measured can be inside a container or can be in its natural form (e.g. a river or a lake). The level measurement can be either continuous or point values.
Continuous Level sensors measure level within a specified range and determine the exact amount of substance in a certain place, while Point-Level sensors only indicate whether the substance is above or below the sensing point. Generally the latter detect levels that are excessively high or low.
Radar Level Transmitter
Electromagnetic waves, typically in the microwave X-band (10 GHz) range.Basically, all types operate on the principle of beaming microwaves downward from a sensor located on top of the vessel. The sensor receives back a portion of the energy that is reflected off the surface of the measured medium. Travel time for the signal (called the time of flight) is used to determine level
Frequency-Modulated Continuous Wave
FM - CW, or frequency modulated continuous wave, radar is an indirect method of distance measurement. The transmitted frequency is modulated between two known values, f1 and f2, and the difference between the transmitted signal and the return echo signal, fd, is measured. This difference frequency is directly proportional to the transit time and hence the distance.