NDC BETA LaserMike LaserSpeed Pro 8500-4, Инструкция по эксплуатации

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3-2 LaserSpeed Pro 8500-4 Instruction Handbook: Installing the System
3.2.1 Mounting Distance
When the material is within the depth of field, the gauge makes accurate measurements. Since the best sig-
nal comes from the center of the depth of field, the center is the source of the best measurements. This is
because the two laser beams totally overlap at the center of the beam crossings and all of the laser power is
used to form fringes.
At the edges of the depth of field, however, some beam-crossing areas overlap and some do not. The areas
that overlap form fringes and thus yield useful Doppler signals; the areas that do not overlap do not form
fringes; rather, they produce only noise with no Doppler signals. Any measurements made outside the depth
of field may not be reliable.
3.2.2 Laser Safety
When mounting of the gauge, ensure that the laser beams are blocked by machinery or beam blocks when
material is not present in the measurement area.
3.2.3 Environmental Conditions
3.2.3.1 Ambient Temperature
All LaserSpeed gauges have a built-in cooling system for applications in which ambient temperatures exceed
45ºC.
Cooling fluids can be routed through the gauge using the 1/8-inch NPT fittings on the back of the gauge. Typ-
ical flow rates of 1.5 liters/minute for water and 50 liters/minute for air are sufficient. There is minimal pres-
sure drop through the gauge, so supply pressure can be very low.
Ensure that the water temperature is above the condensation temperature or dew point, to prevent condensa-
tion from collecting on the front window of the gauge. If water condenses on the optical window, the laser
beams could be blocked, resulting in reduced performance or loss of function.
3.2.3.2 Coolant
In applications with coolants on the material, an air jet may be required to remove the coolant from the meas-
urement area. Since the speed of the coolant is generally different from that of the material, erroneous meas-
urements could result. When incorporating an air jet, be sure to blow the coolant from the measurement vol-
ume at 90° from the material’s motion. If the coolant is blown off in the same direction the material is moving,
the air
velocity can add or subtract from the material’s velocity; this too may cause erroneous measurements.