28
Capacitive electrodes EL 4 … 20 mA - compact
Set-up
value to a known level, you can modify the
current with the plus and minus keys. Each time
you push the key, the current value changes in
10
µ
A-steps.
When you keep the key pushed, the value
changes with raising speed.
Example: When you know that your vessel is
filled to 90 % and should be filled to 100 %,
then you can enter under the min. adjustment a
value of 18,4 mA.
20 mA - 4 mA = 16 mA
16 mA * 90% = 14,4 mA
14,4 mA + 4 mA = 18,4 mA
It is recommended to connect an amperemeter,
see 3.2 Electrical connection. You can monitor
the current value during modification. When you
keep the key pushed, the value changes
automatically and with increasing speed. The
difference between min. and max. adjustment
should be at least 20% or 3,2 mA.
(+/-)
set 20 mA
(+)
increase current
(-)
reduce current
3 Integration time
When you want to adjust the integration time
(damping), set the rotating switch to position 3.
With the plus and minus keys you can double
or halve the value of the integration time step
by step. As a standard feature an integration
time of 0,5 seconds is adjusted. Count how
often you have pushed the key, so that you can
adjust the time correctly. If you are not sure, set
the integration time to the preadjusted value of
0,5 s by pushing both keys together. Then
repeat the adjustment.
After the adjusted integration time 63 % of the
measured value change are available at the
output.
The following integration times can be chosen
on the oscillator: 0,5; 1; 2; 4; 8; 16; 32; 64;
128; 256 (s)
(+/-)
0,5 s
(+)
increase time
(-)
reduce time
Example: To adjust an integration time of 8
seconds, you have to push the key “+“ 4 times.
4 Reverse characteristics
With this function you can reverse the
characteristics of the current output. The
reverse characteristics is visible on the
amperemeter.
(+/-)
4 ... 20 mA
(-)
4 ... 20 mA
(+)
20 ... 4 mA
5 Linearisation
With this function you can activate the saved
linearisation curve. As a standard feature the
curve for cylindrical tank is saved.
On CAP E 32 H you can enter other
linearisation curves via VVO. In this case there
is no preadjustment necessary on the oscillator.
(+/-)
linearisation off
(+)
linearisation on
(-)
linearisation off
6 Sensor optimization
Mode 1 = Phase angle 90
°
Mode 1 is a pure capacitance measurement,
the ohmic resistance is not considered in the
measuring result.
Application:
- standard adjustment
- non-conductive liquids up to approx. 50
µ
S
- compensation of the resistance changes in
liquids
- generally on partly insulated electrodes in
liquids
- non-conductive solids without humidity
contents
- with bad product earth
- with electrodes in conjunction with a
concentric tube
- in non-conductive vessels with ground plate
provided from outside
Mode 2 = Phase angle 45
°
The capacitance and the ohmic resistance are
