Siemens SITRANS LUT400, Руководство по эксплуатации, Страница: 495 / 601

Page 182 SITRANS LUT400 (HART) – OPERATING INSTRUCTIONS A5E33329501
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2.12.1.6. Auto Sound Velocity
Adjusts the speed of sound and changes the distance measurement
calculations. Defined in 2.1.1.Units
.
Condition for use of this feature:
• The acoustic beam atmosphere is other than air
• The acoustic beam atmosphere temperature is unknown
• The Reading accuracy is acceptable at higher material levels only
For best results, calibrate with the level at a known value near Low
Calibration Point.
Using Auto Sound Velocity:
Start with a steady distance at a known high distance value (high distance
value equates to a low level value).
1. Review the distance measurement via LUI for approximately 30 seconds
to verify repeatability.
2. Measure the actual distance (for example, with a tape measure).
3. Enter the actual distance, defined in
2.1.1.Units
.
Repeat this procedure if the atmosphere type, concentration, or
temperature conditions are different from when the last sound velocity
calibration was performed.
2.12.2. Echo Select
2.12.2.1. Algorithm
Selects the algorithm to be applied to the echo profile to extract the true
echo.
For more details, see Algorithm on page 259.
Note: Auto Sound Velocity supports adjustments to distance value only.
Values
Range: 0.000 to 60.000
Note:
In gasses other than air, the temperature variation may not
correspond with the speed of sound variation. Turn off temperature
sensor and use a fixed temperature.
Options
TF TRUE FIRST True First echo
TR TRACKER TRacker
L LARGEST ECHO Largest echo
* BLF BEST F-L
Best of First and Largest
echo
ALF AREA LARGEST FIRST Area, Largest and First