KROHNE BM 700 EN - Manual (Page 14)

Page 14 BM 700 Installation and Operating Instructions
Tank bottom tracing mode (FTB)
The BM 700 includes an additional function for measuring reliably low levels in tanks
with flat bottom and poorly reflecting products (low dielectric constant). This tank
bottom tracing system (abbreviated FTB) is activated in the vicinity of the tank bottom
(max. 20% level). Given higher levels, the normal measuring method is used
(reflection from the product surface).
If the measurement jumps to the correct level only after filling above a certain level
(approx. 0.3-1.0 m), you can activate the FTB function Fct. 3.5.7 „PARTIAL“. The
relative permittivity
ε
r
of the tank product must be set in Fct. 3.5.8. If it is not known,
enter the figure of 2.0. Since the exact position of the tank bottom must be known for
this process, it is advisable when using the FTB to determine the tank height
automatically with an empty tank, using Fct. 3.5.1.
Conversion table/Volume table
A table consisting of a maximum of 50 points can be stored in the BM 700 for non-
linear or linear conversion of the level, e.g. into a volumetric value. This table,
however, can only be programmed with the PC-CAT program (Fct. 3.7.2).