Endress+Hauser FEC 22 - Additional Settings; Manual switch point adjustment

6 Additional Settings
This section describes additional settings which can be carried out after
commissioning and calibration.
6.1 Manual switch point adjustment
FunctionAfter one calibration (probe uncovered or probe covered), the switch point difference
∆C (factory-set value=2 pF) can then be adjusted manually to 4 pF, 8 pF, 16 pF or 32 pF
so that switch point still operates reliably even when the probe is encrusted.
After calibration with an uncovered probe, the switch point capacitance then
increases by ∆C resulting in the higher capacitance: C
S
=C
L
+ ∆C. After calibration
with a covered probe, the switch point capacitance then decreases by ∆C resulting in
the lower capacitance: C
S
=C
H
- ∆C.
Procedure
• After calibration (probe
uncovered or probe
covered) turn the rotary
switch to Position 1
(factory-set value:
∆C = 2pF).
• Press the left key
repeatedly until the
appropriate LED in the
chain lights up at the
required value of ∆C.
The switch point
capacitance C
S
is then
adjusted by the value ∆C.
Note!
Increasing the switch point difference ∆C leads to a reduction in the sensitivity
of the measuring system. After a calibration with both uncovered and covered probe
(see Section 5.4), the switch point difference is determined by the two calibrations
and cannot be altered.
Note!
1
3
7
∆C∆C
1x
0x
2x
4x
3x
2pF4pF
32 pF
16 pF
8pF
=
∆c∆c
7
1
3
BA160Y61
Fig. 6.1
Manual switch point adjustment
Elektronic insert FEC 22 6 Additional Settings
Endress+Hauser 33