VEGA VEGADIF 65 4 … 20 mA_HART - Manual (Page 51)

51
6 Adjustment with the display and adjustment module PLICSCOM
VEGADIF 65 • 4 … 20 mA/HART
36128-EN-130417
1. Edit the bar value in the menu item "Max. adjustment" with [OK].
Max. adjustment
100.00 %
DP
- + =
0.5000 bar
0.0000 bar
Information:
If the instrument has not yet been adjusted, the displayed pressure for
100 % corresponds to the nominal measuring range of the sensor (in
the above example 500 mbar).
2. Set the requested mbar value with [->] and [OK].
3. Confirm with [OK] and move to the menu overview with [ESC].
For an adjustment with flow, simply enter the actual measured value
indicated at the bottom of the display.
The max. adjustment is finished.
For level measurement, a linearization is necessary for all vessels in
which the vessel volume does not increase linearly with the level - e.g.
in a cylindrical or spherical tank - and the indication or output of the
volume is requested.
Respective linearisation curves are stored for these vessels. They
indicate the relation between the percentage level and the vessel vol-
ume. By activating the suitable curve, the percentage vessel volume
is displayed correctly.
Linearization curve
Linear
Enter the requested parameters via the appropriate keys, save your
settings and jump to the next menu item with the [->] key.
Caution:
Note the following if the VEGADIF 65 with corresponding approval is
used as part of an overfill protection system according to WHG (Water
Resources Act):
If a linearization curve is selected, the measuring signal is no longer
linear to the level. This must be taken into consideration by the user,
particularly when setting the switching point on the limit signal indica-
tor.
The square of the flow is proportional to the pressure difference at the
orifice or the back pressure probe:
(Q
n
) 2 = c • ∆p
To provide a linear relation between flow and output variable, an
extraction by root is necessary:
Q
n
= √(c • ∆p)
The VEGADIF 65 has a root extraction function. It is selected in the
menu item "Linearization curve".
Linearization curve with
level
Linearization curve with
flow