BKI16ATEX0018X ♦ htk4014a0600p_03 ♦ 43 / 76
This is illustrated below – the value in the box is the displayed value:
level/mm
No level reflection inside detection delay zone
V/V
8850mm(3)
8850mm
2
3
9
level/mm
Level reflection inside dead zone
V/V
8850mm(3)
8850mm
2
3
8
level/mm
Level reflection outside dead zone
V/V
8850mm(3)
8600mm
2
3
7
4
5
6
1 Height of tank fitting
2 Detection delay (Fct.1.5.1=120 mm)
3 Dead zone limit (Fct.1.1.2=150 mm)
4 Emitted signal
5 Flange reflection (masked)
6 Masked zone (all signals here are ignored)
7 Level reflection outside dead zone – true level displayed
8 Level reflection inside dead zone – level at dead zone limit displayed (frozen)
9 Level reflection inside detection delay zone – not detected by gauge and level
at dead zone limit displayed (frozen)
Dead zone: configuration of user menu PCSTAR 2 function 1.1.2
(HART
®
Fct. 2.1.1.4)
The top dead zone is the minimum measuring distance between the
gauge flange facing (the reference point) and the product. The various
probes for the MicroTREK 2-wire have differing top dead zones and these
are given in section 5.2.3: Probe measurement limits.
Why is configuration of the dead zone important?
The gauge will not display measurements taken here - the reading is
blocked on reaching this zone.
This will avoid the gauge confusing the true level with a parasite (i.e.
flange) as the product nears the tank fitting and thereby displaying a false
reading. It should be noted that although the reading is frozen, the gauge
will continue to follow the reflection. The PCSTAR 2 F8-marker menu will
display “Tank full” in this zone.
What is the difference between these functions:
PCSTAR 2 Fct 1.1.2/ HART® Fct. 2.1.1.4: Dead zone
PCSTAR 2 Fct 1.5.1/ HART® Fct. 2.1.5.3: Detection delay?
The “detection delay” function masks all signals (i.e. none are detected by
the gauge) up to a defined distance from the flange facing. The detection
delay zone size is never greater than the dead zone size.
The PCSTAR 2 F8-marker menu will display “Tank full” and “Level lost” in
this zone.
*(3) = 985 mm Dead zone configured limit in terms of level
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