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5.1.5. Output mode – switch (relay)
In the field for the “Switch-mode”, one can select “Hysteresis” or “Window”.
The field for “Type” is to determine the switch action of the relay, NO = Normally Open (activate to close), NC
= Normally Close (activate to open).
Under
“Measuring range”
in the field “From” the low value of the measuring range can be entered and in the
field “To” the high value.
The hysteresis of the set point is entered as a percentage of the
measuring range.
[measuring range] = high measuring value – low measuring value
e.g. hysteresis
set point = 500 Nm
3
/h and reset point is 450 Nm
3
/h
Hysteresis = 50 Nm
3
/h = 0.5 % of measuring range
Hysteresis
When the measurement value reaches
set point 1
, the relay will be acti-
vated. The value at the reset point is the value at set point 1 minus the
hysteresis.
e.g. set point 1 = 100 Nm
3
/h and the hysteresis 5 Nm
3
/h.
the relay switches at 100 Nm
3
/h. The reset point is at 96 Nm
3
/h.
Hysteresis = 5 Nm
3
/h = 5% of the measuring range
Window
The relay is activated as long as the measuring value is between the
values of
set point 1
and
set point 2
.
The hysteresis of each set point is fixed at 0.2% of the measuring
range.
e.g.: set point 1 = 100 Nm
3
/h; set point 2 = 80 Nm
3
/h;
hysteresis of each set point is 1 Nm
3
/h (0.2% of 500 Nm
3
/h)
t
Nm
3
/h
0
1
0
1
set point 1
set point 2
t
Nm
3
/h
0
1
0
1
NC (activate to open)
NC (activate to open)
NO (activate to close)
NO (activate to close)
set point 1
Hysteresis
80 Nm
3
/h = set point 2
100 Nm
3
/h = set point 1
99 Nm
3
/h = set point 1 - hysteresis
79 Nm
3
/h = set point 2 - hysteresis
