NIVELCO EasyTREK SCD-31 4 Series, Инструкция по установке и программированию, Страница: 25 / 32

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P29 - - - - Blocking out of object FACTORY DEFAULT: 0
One object in the tank/silo disturbing measurement can be blocked out. Enter distance of the object from the transducer. Use the Echo Map (P70)
to read out the precise distance of disturbing objects.
P31: - - - - Sound velocity at +20 °C (+68 °F) [m/s or ft/s] FACTORY DEFAULT: metric: 343.8 m/s, US: 1128 ft/s
Use this parameter if the sound velocity in the gases above the measured surface differs largely from that of in air.
Recommended for applications where the gas is more or less homogeneous. If it is not, the accuracy of the measurement can be improved using
the
32-point linearization (P48, P49).
For sound velocities in various gases see section “Sound Velocities”.
P32: - - - - Specific gravity [kg/dm3] FACTORY DEFAULT:
0
If you enter value (other than “0”) of specific gravity in this parameter, the weight will be displayed in EView instead of VOL.
P33: - - - - Manual echo selection by moving the Measuring Window FACTORY DEFAULT: 0
A so-called measuring window is formed around the echo signal (See scheme on the next
page.). The distance of the target will be calculated from the flight time in accordance with
the position of the measuring window.
Use this parameter if the EasyTREK unambiguously selects a wrong echo; for example,
the echo reflected from the surface is much weaker than the interfering one(s) (see figure
beside and on next page).
Enter the distance of the correct echo and the software will move the measuring window
and calibrate itself to the echo found there. To determine the distance of the correct echo,
either use the Echo Map (to load-in a value from the Echo Map, see parameter
P70 ), or
measure the distance with an appropriate device, and enter this value in P33 .
If this parameter has been used (P33 is not 0), its value will be continuously updated with the valid echo position. This means, that in case of a
power loss, the EasyTREK will restart the signal processing with the measuring window at the last updated position. To switch-off this function, set
P33 = 0 .