19
P31:
Sound velocity at 20
_
C (m/sec or ft/sec depending on P00(c) )
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 linearisation (
P48
,
P49
).
For sound velocities in various gases see section “Sound Velocities”.
FACTORY DEFAULT: Metric (
P00: “EU”
): 343.8 m/s, US (
P00: “US”
): 1128 ft/s
P32:
Specific gravity
If you enter value (other than “0”) of specific gravity in this parameter, the weight will be displayed instead of VOL.
FACTORY DEFAULT:
0
[kg/dm
3
] or [lb/ft
3
] depending on P00(c)
P33: (m)
Manual echo selection by moving the Measuring Window
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 Echotel 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
.
1.
2.
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 Echotel will restart the signal processing with the measuring window
at the last updated position. To switch-off this function, set P33= 0.
FACTORY DEFAULT: 0
(locked on the disturbing echo)
Received
signal amplitude
Window
signal (comp.)
Window
signal (comp.)
Window
signal (comp.)
Displayed DIST
value (of the disturbing echo)
(flight time)
Displayed DIST
The value is correct.
Setting: P33=4.00 (results in shifting the measuring window to 4m)
Measuring Window finds the echo from the surface
5.2
3.85