The LM80 is mounted on top of a storage vessel aiming downwards towards the surface. Using the visible laser pointer, the position and angle of the LM80 can be adjusted so that the instrument measures all the way to the bottom of the vessel. Settings such as: the distances for the 4-20 mA output; and the relay switching points, can be entered into the instrument either before installation or in situ using the laser configuration (LCD2) accessory.
Another recommended accessory is the stainless steel dust tube (P801) which keeps the
optical system of the LM80 clean for long periods.
The LM80 is able to measure the level in tall silos because of the inherent long distance capability of laser technology. The laser has a natural advantage
because it gets strong, clear signals from most types of granular solid materials. As the laser beam doesn’t spread out and lose strength as it travels, there is little signal loss with increased distance.
Auto-ranging is a hardware feature which increases the range of the internal timing circuitry of the LM80. It does this in response to the 4-20mA or relay set points that are entered by the user. If these settings are less than 35 m (114.8 ft) then automatic “Range
1” is used. Between 35 m (114.8 ft) and 85 m (278.9 ft), automatic “Range 2” is selected. As the LM80 switches between these ranges there is no loss of accuracy, only a slight reduction in measuring speed.
The ultimate limit of range for the LM80 depends on the reflectivity of the material being measured, not on the height of the vessel. Dark colored materials can be measured over a shorter range than light colored materials. When the LM80 is used for positioning applications with a reflective target it can measure to a maximum
distance of 150 m (500 ft).