Siemens sitrans PROBE LU - Output Parameters; Transducer Block (TB) Values; AIFB1 Configuration

Page 90 SITRANS Probe LU (PROFIBUS PA) – INSTRUCTION MANUAL 7ML19985JB02
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H: Parameters
2.7.3.8. Sound Velocity at 20
o
C (default 344.13)
Sound velocity through the medium at 20
o
C. (Sound velocity in air is
344.1 m/s or 1129 ft/s.)
2.7.3.9. Offset and Velocity calibration
1. Offset calibration
You can specify a fixed value to apply to all measurements. Use this
function if the reported level is consistently high or low by a fixed
amount (stored in Sensor Offset).
Open menu Device – Offset and Velocity Calibration, select the
option to change calibration, select the calibration type, then enter
new calibration value.
2. Sound Velocity calibration
Used to calculate sound velocity when either the acoustic beam
environment is other than air or unknown, or the reading accuracy is
acceptable only at higher material level.
For best results, calibrate with the level at a known value close to
empty, and manually determine the actual distance from sensor to
material level.
Open menu Device – Offset and Velocity Calibration, select the
option to change calibration, select the calibration type, then enter
new calibration value.
2.7.4. Echo Sampling
2.7.4.1. Sampling up
1
(default 5)
Once echo is outside the window, a specified number of consecutive
echoes must appear above the echo locked onto, before measurement is
accepted as valid.
Note: If a velocity calibration is performed after the sensor offset
value has been set manually, the sensor offset value will be reset
to 0.
Note: The Echo Sampling parameters are for use by authorized Siemens
Service personnel or technicians familiar with Siemens echo processing
techniques.
1.
This parameter is for use only by Siemens service technicians.