Additional Settings; Manual Switchpoint Adjustment - Endress+Hauser FEC 22 Betriebsanleitung

Elektronic insert FEC 22

6 Additional Settings

This section describes additional settings which can be carried out after
commissioning and calibration.
6.1 Manual switch point adjustment
After 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
with a covered probe, the switch point capacitance then decreases by ∆C resulting in
the lower capacitance: 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 is then
S
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.
Endress+Hauser
- ∆C.
= C
S H
∆C ∆C
8 pF
= 2 pF 4 pF 16 pF
4x
3x
2x
1x
0x
+ ∆C. After calibration
= C
S L
32 pF
1
7 3
1
7
6 Additional Settings
Function
∆ ∆
3
c c
Fig. 6.1
Manual switch point adjustment
Note!
33