SMAR ld301, Инструкция по эксплуатации и техническому обслуживанию

Страница: 28 / 70

LD301- Operation and Maintenance, Instruction manual
3.8
Figure 3.2 – Square Root curve with Cutoff point
NOTE:
In bumpless cutoff mode the gain below the cutoff point is given by the
equation:
For example, at 1% the gain is 10, i.e., a 0.1% error in differential
pressure, gives a 1% error in Flow reading. The lower the cutoff, the
higher is the gain.
SQRT**3
-
Square Root of the Third Power.
The output will be 0.1 √ x
3
. This function is used in open channel Flow measurement
with weirs or flumes.
SQRT**5
-
Square Root of the Fifth Power. The output will be 0.001 √ x
5
. This
function is used in open channel Flow measurement with V-notch weirs.
It is possible to combine the previous functions with a table. The flow can be connected
according to the table to compensate, for example, the variation of Reynolds number at
the flow measurement.
TABLE - The output is a curve formed by 16 points. These points may be edited
directly on the XY Table of the LD301 . For example, it may be used as a camber
table for tanks in applications where the tank volume is not linear in relation to the
measured pressure.
SQRT & TABLE
-
Square root and Table. Same application as square roots, but
also allows additional compensation of, e.g., varying Reynolds number.
SQRT**3 & TABLE
-
Square Root of the Third Power AND TABLE.
SQRT**5 & TABLE
-
Square Root of the Fifth Power AND TABLE.
TABLE POINTS
If the option TABLE is selected, the output will follow a curve given in the option TABLE
POINTS. If you want to have your 4-20 mA proportional to the volume or mass of fluid
inside a tank, you must transform the pressure measurement "X" into volume (or mass)
"Y" using the tank strapping table, as shown in
Table 3.3.
cutoff
G
10
=