Endress+Hauser FEC 22 - Calibration Procedures; Calibration when probe uncovered; Calibration when probe covered; Calibration when probe uncovered and covered

5.2 Calibration when probe uncovered
Procedure
• To calibrate an uncovered probe, turn
the rotary switch to Position 6.
• When first delivered or after a reset the
extreme left LED in the chain lights up:
no calibration carried out.
• Press the right key for 2 s.
• The extreme right LED in the chain
lights up. The calibration has been
acknowledged and stored.
• The instrument is now on stand-by.
After a calibration with an uncovered probe the capacitance when empty (C
L
)isstored.
The switch point C
S
is then determined by the threshold value ∆C (factory-set
value = 2 pF) with C
S
=C
L
+ ∆C.
5.3 Calibration when probe covered
Procedure
• To calibrate a covered probe turn the
rotary switch to Position 8.
• When first delivered or after a reset the
extreme left LED in the chain lights up:
no calibration carried out.
• Press the right key for 2 s.
• The extreme right LED in the chain
lights up. The calibration has been
acknowledged and stored
• The instrument is now on stand-by.
After calibration with a covered probe the capacitance when probe covered (C
H
) is
stored. The switch point C
S
is then determined by the threshold value ∆C (factory-set
value = 2 pF) with C
S
=C
H
- ∆C.
5.4 Calibration when probe uncovered and covered
A calibration with both uncovered and covered probe is recommended to ensure
maximum operational safety. An uncovered or covered probe calibration can always
be supplemented at a later date by an appropriate covered or uncovered probe
calibration. When both calibrations are carried out, the current switch point will be
placed halfway between the two calibration points. The switch point is specified by
C
S
= 0.5 x (C
L
+C
H
). See Section 5.2 and 5.3 for carrying out a calibration with both
uncovered and covered probe.
Note!
Switch point optimisation can no longer be activated when both an uncovered and
covered calibration has been carried out. Should it be active when a supplementary
calibration is to be carried out, then the function is automatically switched off.
Note!
1
3
7
7
3
1
2s
ONOFF
BA160Y53
Fig. 5.2
Calibration when probe
uncovered
1
3
7
2s
ONOFF
7
3
1
BA160Y54
Fig. 5.3
Calibration when probe
covered
5 Commissioning Elektronic insert FEC 22
32 Endress+Hauser