VEGA Capacitive electrodes EK Profibus PA - Manual (Page 41)

Capacitive electrodes EK - Profibus PA 41
Setup
Max. adjustment
There must be max. level in the vessel. If you
push the button Save, the output is set to the
entered percentage value. You can also
assign a certain percentage value to a known
level.
For example, if you know that your vessel is
filled to 90 %, this can be entered under max.
adjustment.
Adjustment without medium (dry
adjustment)
Under certain circumstances, an adjustment
can also be carried out without medium with
the help of the processing software VVO.
The requirements for an adjustment in m are:
In conductive medium:
- electrode is fully insulated
The following criteria apply to the
conductivity:
Mode 1 (90°) Mode 2 (45°)
w. conc.tube > 50 µS/cm >150 µS/cm
w.o. conc.tube >100 µS/cm >300 µS/cm
In non-conductive medium:
- concentric tube electrode
- you know the DK value of the medium
If you already know the electrode
capacitance of another, similar measurement
loop (same electrode, same installation
conditions, same medium), you can also
carry out a dry adjustment in pF.
With an unimmersed electrode, first carry out
an offset correction (only for adjustment in m:
Instrument data - Parameter adjustment -
Additional functions). Go again to the function
"Adjustment without medium".
You can choose if you want to carry out the
adjustment in pF or in m. If you have chosen
adjustment in m, you have to enter whether
your medium is conductive or non-
conductive. If the medium is non-conductive,
you also have to enter the DK value.
The above table shows you the conductivity
criteria applicable to capacitive measurement
and whether you have to choose
"Conductive" or "Non-conductive".
If you have chosen m, you can assign a
corresponding value in m to the percentage
value.
Example
0 % = 0.2 m
100 % = 3.2 m
Attention! Please do not confuse this offset
with the offset correction (instrument data/
parameter adjustment/additional functions).
Adjustment with medium
Min. adjustment
There must be min. level in the vessel. If you
push the button Save, the output is set to the
entered percentage value.
For example. if you know that your vessel is
filled to 10 %, this can be entered under min.
adjustment.