OTT PLS - Page 19

Using the commands "setting/reading the upper/lower limit" you can scale the
measurement output of an OTT PLS to a smaller measuring range. Where you do
n
ot require the whole measuring range, this has the advantage that a higher
resolution for the 4 … 20 mA interface can be achieved. Example: A measuring
range of 16 mA is available for 5 m water level change (e.g. lower limit =
+10,000 m; upper limit = +15,000 m. See Figure 7). At the same time, you can
use these commands to apply a linear offset (positive/negative) to the measured
v
alues of the 4 … 20 mA interface.
15 m =
^
20 mA
(upper limit)
10 m =
^
4 mA
(lower limit)
Measurement
output
scaled to
5 meter
water level
change
Figure not to scale!
20 m =
^
20 mA
0 m =
^
4 mA
with scaling
Measurement output
without scaling
Fig. 7: Scaling measurement output
of the 4 … 20 mA interface to a
smaller measuring range.
Example: OTT PLS with
measuring range 0 … 20 m.
19