KROHNE BM 70 M - Manual (Page 42)

42 BM 70 M
The unit selected here is also valid for the following functions:
Scaling 4 mA value, current output
Fct. 3.3.3
Scaling 20 mA value, current output Fct. 3.3.4
Threshold (limit value), switching output Fct. 3.6.3
Hysteresis, switching output Fct. 3.6.4
Display range:
0.00
- 30000.00 m 3
0 - 9999999 Liter
0 - 7925161 US Gal
0 - 6599265 GB Gal
0.0 - 999999.9 Ft3
0.0 - 99999.9 bbl (petroleum barrel)
Note:
When the display is set to Liter, ft³ or Barrel, it is possible that the max. volume
will no longer be shown. In such cases, the special symbol " == " is displayed
and a change possibly made to a different unit. The current output will in any
case output the correct value.
Conversion measurement requires that a conversion table be set with the PC-CAT program. By
means of this table a conversion value is allocated to each level value (level / conversion pairs).
The values are linearly established (interpolated) between 2 points.
Also, for the local display an arbitrary (max. 10-character) text (Fct. 3.2.4) can be defined as a
unit under Fct. 3.2.4. Internally, this "user unit" is treated in the conversion in the same way as "
m³ ".
Examples of application and setting: see Sect. 8.5
Reflection units
The measuring range for "reflection" has a fixed setting of 0...100 (whole numbers). The
"reflection" measured value is a relative measure of the strength of the reflected signal, converted
into an exponential scale: each number step is approximately equivalent to a change by 0.4 dB;
in other words, about 8 steps signify a doubling of the signal strength. At full reflection, a value of
approx. 90...100 is measured.
Where measuring distances are greater, the natural weakening of the signal is automatically
allowed for in the measured value (does not apply to stilling wells, i.e. when Fct. 3.1.6 = YES).
The measured reflection can be regarded as being a measure of the reflectivity of a product.