Users Manual Part 2

LW2720 Electronic level sensor
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L
SP1
HY
no
nc
t
Fig.3: Single-point mode
L
SP1
SP2
no
nc
t
Fig.4: Two-point mode
L: level
t: time
HY: hysteresis
Window function:
u [SSC1 Config. Mode] must be set to [Window].
The width of the window can be set by means of the difference between [SSC1 Param. SP1] and
[SSC1 Param. SP2] (Ò Fig. Window function).
u [SSC1 Param. SP1] must be greater than [SSC1 Param. SP2].
The normally open or normally closed function is set by [SSC1 Config. Logic]: [no] = normally open /
[nc] = normally closed.
If desired, a hysteresis can be set at the window limits using [SSC1 Config. Hysteresis].
L
SP1
SP2
no
nc
t
W
Fig.5: Window function
L: level
t: time
W: window
The limit values [SSCx Param. SPx] are always absolute to the zero point = reference point (Fig.
Analogue output). The hystereses [SSCx Config. Hysteresis] are always relative to the limit values.
For the switching outputs, a switch-on and switch-off delay of max. 60s can be set (e.g. for especially
long pump cycles). The switch-on delay always refers to the limit value, the switch-off delay always
refers to the hysteresis.
5.3.3 Defined state in the event of a fault (alert mode)
For output OUT2, a state in the event of a fault can be defined.
If a fault is detected or if the signal quality is below a minimum value, the unit changes into the alert
mode and output OUT2 passes into a defined state according to NAMUR recommendation (NE43).
For this case, the response of the output can be set via the parameter [FOU2].
The unit can pass into the alert mode with delay. This can be useful if short-term errors occur or the
signal is reduced briefly (below the minimum value), e.g. due to turbulence or foam formation. The
delay time can be set (parameter [Alert mode delay time]). During the delay time the last measured
value is frozen. If the measured signal is received again in sufficient strength within the delay time, the