Milltronics AiRanger SPL PL-573, Instruction Manual

Page: 89 / 113

PL-573 AiRanger SPL Page 89
Technical Refer
e
nce
The SPL automatic temperature compensation is based on the sound
velocity/temperature characteristics of "air" and may not be suitable for the
atmosphere present. If the atmosphere temperature is variable, frequent Sound
Velocity Calibrations may be required to maintain optimum measurement accuracy.
Sound Velocity calibration frequency may be determined with experience. If the
sound velocity in two vessels is always similar, future calibrations may be performed
on one of the vessels and the resultant Velocity (P653) entered directly for the other
vessel.
If the sound velocity of a vessel atmosphere is found to be repeatable at specific
temperatures, a chart or curve may be developed. Then, rather than performing a
Sound Velocity Calibration each time the vessel temperature changes significantly,
the anticipated Velocity (P653) may be entered directly.
Volume Calculation
The SPL provides a variety of volume calculation features (P050 to P055).
If the vessel to be monitored does not match any of the 8 preset Tank Shape
calculations, a Universal Volume calculation may be used. Use the level/volume
graph or chart provided by the vessel fabricator (or create one based on the vessel
dimensions).
From this graph, determine which Universal Volume calculation will provide the best
results, and select the level vs volume breakpoints to be entered (32 max.).
Generally, the more breakpoints entered, the greater the volume calculation
accuracy.
Universal, Linear (P050 = 9)
This volume calculation creates a piece-wise linear approximation of the level/volume
curve. This option provides best results if the curve has sharp angles joining relatively
linear sections.
Enter a Level Breakpoint at each point where the level/volume curve bends sharply
(2 minimum).
For combination curves (mostly linear but include 1 or more arcs), ensure numerous
breakpoints are entered along the arc, for best volume calculation accuracy.
tank
volume
level