300-R010-45L Datasheet, PDF (7/12 Pages) Magnetrol International, Inc. – Echotel® Model 300/301 Ultrasonic Non-Contact Transmitter For Level, Volume, and Open Channel Flow

MEASUREMENT RANGE CALCULATIONS
OPERATING PARAMETER
SURFACE AGITATION: Surface agitation or waves can degrade
the performance. Moderate agitation results in only slight degrada-
tion of performance. The worst case is when the surface is a good
reflector, but in the wrong direction. (Refer to sensor alignment.)
VAPOR AND STEAM: Vapors in the air space, above the process,
become apparent, and cause problems when the liquid process
temperature is well above the temperature of the airspace. The
greater the difference, the more expected vapor problems. The
problems result from condensation or layering in the sound path,
both of which attenuate the sound signal, degrading performance.
Avoid steam if possible.
To avoid these problems, ensure that the vessel is insulated so that
vapors are less likely to condense. If a vent is used, be sure that the
vent, which is where condensation will form, is well away from
the sensor.
BEAM SPREAD INTERFERENCE: It is strongly recommended
that nothing be allowed within the sensor’s beam, except the liquid
which is being monitored. Often, the signal from the liquid will be
strong, compared to the signal from other sources, such as, ladder
rungs filling process material, support struts, etc. For that
reason,some applications may provide satisfactory results, even
with than 60 interference. Interference from agitator blades is only
an intermittent interference that usually has little effect on perfor-
mance.
It is recommended there be no interference within the 6° half angle
of the sensor beam. If interference is unavoidable, make the inter-
ference as far as possible from the sensor so that the real signal at
the longest distance is stronger than the interference signal.
SENSOR ALIGNMENT: Optimum performance is obtained when
the sensor is perfectly aligned. If the process is not perpendicular to
the sound beam, the sound will not reflect properly back to the
sensor. The effect is significant.
FOAM: Even small thicknesses of foam can attenuate the ultra-
sound and render the system inoperative. If possible, moving the
sensor to an area in the tank where there is less foam, will improve
the performance. Thick, heavy density foams can sometimes pro-
duce a reflection from the top of the foam. The multipliers shown
at right are general guidelines. For further assistance consult
the factory.
DUST: Dust attenuates the sound and results in poor performance.
Even barely perceptible haze in the air can cause significant
attenuation.
AIR MOVEMENT: The movement of air, as possible in an open top
vessel, can create a layer from which the sound will reflect. This will
be most noticeable in applications where vapors or steam tend to
form.
AMBIENT TEMPERATURE: The ambient temperature can have a
significant effect on the sound and on the sensor’s capability to
transmit and receive sound. The most noticeable effect on the
sensor is at the temperature extremes.
CONDITION
PERFORMANCE
MULTIPLIER
Smooth, glass-like surface . . . . . . . . . .1.0
Slight agitation, choppiness . . . . . . . . .0.9
Heavy agitation . . . . . . . . . . . . . . . . . . .0.8
Slight vortex . . . . . . . . . . . . . . . . . . . .0.7
No condensation . . . . . . . . . . . . . . . . . .1.0
Little condensation . . . . . . . . . . . . . . . .0.9
Much condensation/ foggy
appearance . . . . . . . . . . . . . . . . . . . . . .0.8
No interference within 3.5°
half beam angle . . . . . . . . . . . . . . . . . . .1.0
Agitator at speed less than 60 RPM . . .1.0
Agitator at speed greater than
60 RPM . . . . . . . . . . . . . . .Consult factory
Interference outside 4°, far from
sensor (in bottom third of range) . . . . . .0.8
Interference outside 4°, near to
sensor (in top third of range) . . . . . . . . .0.5
Beam perpendicular to liquid surface . .1.0
Beam 4° off from perpendicular . . . . . .0.5
No foam . . . . . . . . . . . . . . . . . . . . . . . .1.0
Light froth, less than 0.25" thick . . . . . .0.8
Light foam, less than 0.5" thick . . . . . .0.5
Light foam, more than 1" thick . . . . . . .0.1
No dust . . . . . . . . . . . . . . . . . . . . . . . . .1.0
Haze, barely perceptible . . . . . . . . . . . .0.7
Slight dust . . . . . . . . . . . . . . . . . . . . . . .0.4
Heavy dust . . . . . . . . . . . . . . . . . . . . . .0.1
No air movement . . . . . . . . . . . . . . . . .1.0
Open vessel, but sensor below rim . . .0.8
Open air movement in sound path . . . .0.7
-20° to +140° F (-29° to +50° C) . . . . . .1.0
-40° to -20° F (-40° to +29° C) . . . . . . . .0.9
+140° to +160° F (+50° to +70° C) . . . .0.9
PRESSURE: Sound requires air molecules to be able to travel.
Sound will not travel in a vacuum. Likewise, higher pressures will
allow the sound to continue without decay, which can cause prob-
lems with multiple echoes.
-10° to +50 psig (0.689 to +3.45 bar) . .1.0
Pressures outside
above rating . . . . . . . . . . . .Consult factory
Multiply all values together in the application column
Choose a range value from the Maximum Range Table
Maximum allowable measurement range for this application
APPLICATION
x
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