IFM LK81 Manuel De L'utilisateur page 38

Hysteresis function (Hno, Hnc):
The hysteresis keeps the switch-
ing state of the output stable if
the level of the medium varies
about the preset value.
With the level rising, the output
switches when the switch-on
point has been reached (OP /
SPx). With the level falling, the
output does not switch back
until the level falls below the hys-
teresis value (for OUT-OP) or
below the reset point rPx (for
OUT1 ... OUT3).
The hysteresis for OP is fixed. It is a few millimetres.
The hysteresis for SPx can be adjusted: First the switch-on point is set,
then the switch-off point with the requested distance.
Window function (Fno, Fnc; only for OUT1 ... OUT3):
The window function enables
the monitoring of a defined
acceptable range. When the level
of the medium varies between
the switch-on point (SPx) and the
switch-off point (rPx), the output
is switched (window function /
NO) or not switched (window
function / NC).
The width of the window can be
set by means of the difference
between SPx and rPx. SPx =
upper value, rPx = lower value.
38
L = level
acceptable range
L
SP
rP
1
0
1
0
L = level
hysteresis
Hno
Hnc
t
Fno
Fnc