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Go to Specific Subject: Laser Level Instrumentation and Measurement |
Laser Radar Instrumentation depends on knowing the speed of light, approximately 0.3 meters per nanosecond. Using that constant it is calculated how far a returning light photon has travelled to and from an object: Distance = (Speed of Light x Time of Flight) / 2. It works as follows;
Laser Technology is utilised in accurate Laser Instruments for Industrial Level and Measurement Applications.
of the Object
Measurements are not generally affected by the reflectivity
of the Object . Highly reflective objects may saturate some laser detectors,
while the return signal from low-reflectivity objects may occasionally be too
weak to register as valid.
Laser radar is an "active illumination" technique
that, unlike photography, does not depend on ambient illumination. It works
during the day or at night.
and Reflections/Angle of Measurement
A strong sunlight reflection off a highly reflective target
may "saturate" a receiver, producing an invalid or less accurate
reading. However, laser measurements are not usually affected by other
Laser measurements can be weakened by interacting with dust
and vapour particles, which scatter the laser beam and the signal returning from
the target. However, using last-pulse measurements can reduce or eliminate this
Angle of Repose
Laser measurements can be made to targets at any angle.
Noise and Radiation
Laser Measurement is not affected by background noise.
Instrumentation generally determines baseline radiation levels to ensure that it
does not interfere with measurements.
and Temperature Variations
Laser measurements are based on the speed of light and are
unaffected by temperature variations.
Pressure and Off-Gas Layers
Laser Measurement is unaffected by pressure or vacuum
variations, or off-gas layers.
Thanks to OPTEK for the above information.
Introduction to Laser Instruments and Applications - When the laser was invented in 1960, it was amazingly, a solution looking for a problem. While the laser's weapons potential was clear, most of the uses of lasers that have changed the World were not foreseen even by the so-called experts of the time. In this chapter, we touch on perhaps one tenth of one percent of those where lasers are now indispensable, or at least have the potential to be in the future - from www.repairfaq.org.
Lasers come to Level Measurement - Laser-level technology is expanding options in sensor applications and this article covers the good and bad points of this new measurement technique.From David W. Spitzer and ControlGlobal.com
Laser Level Measurement - David W. Spitzer - The basics, a short description - Part 1 and Part 2 - from appliedmc.com.
The Lowdown on Radar Level Measurement - Free-Air or Guided-Wave -- Which Do You Use When? - Walt Boyes - Radar level measurement is basically divided into two groups, free-air and guided-wave - from the excellent Control Global.
Considerations for Continuous Level and Inventory Monitoring of Powder
and Bulk Solids - Continuous level measurement is about one thing,
e.g. answering the question “how much stuff do I have”. There are many
applications where you need to know how much material is in a bin, silo or other
vessel type. Usually the desired engineering unit is expressed in terms of
volume or weight. “Measuring” volume or weight is not always the most
practical approach, sometimes it isn’t even viable. Take those silos you have,
how do you weigh the ingredients if the silos weren’t installed with load
systems? Not an easy or inexpensive question to answer. So what do we do? This
is where continuous level measurement sensors and systems come into play and
offer a viable and cost effective approach.The purpose of this white paper is to
discuss and inform about the application considerations when you need to measure
the level of material continuously or simply determine on a continuous basis how
much stuff you have in your vessels - whilst this document is about many of the
technologies available it does have a section on Laser level - from Blue Level
A Dozen Ways to Measure Fluid Level -
How They Work - This
article from ABB covers most level measurement techniques, however there is a
small section on Laser Instrumentation for the Process Industry on page 6.