.52+1(
BM 70 A Kurzanleitung
Seite: 12
4. Entwurf 03/97
Explanatory notes
Tank height
The tank height (Fct. 3.1.1) for the BM70 A is defined as the distance between the
top edge of the tank connecting flange and the bottom reference point. The bottom
reference point is that “point“ in the tank on which the microwaves of the BM 70 A
impinge and from which they are reflected. This may be the tank bottom
(symmetrical tank with flat bottom) or the non-horizontal part of the bottom (e.g. tank
with dished bottom) or an additionally fitted plate. The BM 70 A cannot measure
below this point (“sump“ in the tank).
Note: When the tank is completely empty and the tank bottom provides good
reflections (flat, not dished bottom!), the tank height can also be automatically
determined with the aid of Function Fct. 3.5.1 AUTO TANKH. Before confirming,
check carefully that the proposed tank height is plausible!
Block distance
The “block distance“ function (Fct. 3.1.2) defines a zone below the top reference
point in which measurements are not meant to take place. The value should be at
least 10 - 20 cm greater than the length of antenna extension, or at least
20 cm in the case of the Wave-Stick.
Signals within the block distance are suppressed; a rise in the tank filling above this
limit (response threshold) will lead to a measuring result corresponding to a distance
= block distance, when Fct. 3.5.6 BD-IDENT. is switched on.
Scaling of the current output
The scaling of the current output (Fct. 3.3.3: level 1 = 4mA ; Fct. 3.3.4: level 2 =
20mA) should if possible lie within the measuring range (between bottom reference
point and response threshold).
Sumpf
nicht
messbare
Behälterzone
Behälterhöhe
(Fct. 3.1.1)
Fct. 3.1.4
Referenzpunkt oben
(Oberkante Behälter-Anschlussflansch)
Blockdistanz (Fct. 3.1.2)
Ansprech-
Stromausgang
20
mA
Imax
(Fct. 3.3.4)
4
Imin
(Fct. 3.3.3)
Referenzpunkt unten
(Behälterboden / Peilstelle)
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Fct. 3.1.5
schwelle
Messbereich
mA
[Bsp: 5.30 m]
[Bsp: 0]
[Bsp: 0]
[Bsp: 0.6 m]
[Bsp: 0.4 m]
[Bsp: 4.0 m]
