Busch-Jaeger Busch-ComfortTouch, Product Manual

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20.3.19 Details about threshold values with hysteresis
20.3.19.1 Behaviour
The module checks whether the incoming comparison value on
Input 0
lies above or below a
threshold value. In contrast to the Greater/Less comparator, a certain tolerance range can be
defined (hysteresis). The approach direction of the comparison values (from above or below) to
the threshold is also taken into account. This logic module can be used to generate exact logic
signals from slowly executing processes, for example, for the switching signal of a thermostat-
controlled heating control.
A lower and upper threshold are required for this logic module. The thresholds are defined via
Input 1
and
Input 2
.
Results are output as follows on the outputs (see also the graphic below):

If the comparison value first exceeds the lower and then the upper threshold,
thus crossing the tolerance range from
below to above , the result 1 (logical
"true") is output on the
Output 0
. If the comparison value subsequently falls be-
low the lower threshold again, the output
Pin 3
is reset to 0 (condition for
Out-
put 1
, see below).

If the comparison value first falls below the upper and then the lower threshold,
thus crossing the tolerance range from
above to below , the result 1 (logical
"true") is output on the
Output 1
. If the comparison value subsequently exceeds
the upper threshold again, the
Output 1
is reset to 0 (condition for
Output 0
,
see above).

On the
Output 2
the result 1 is output (logical "true"), as soon as the compari-
son value generally exceeds the upper threshold (without condition). Otherwise
the output value is 0 (logical "false").

On the
Output 3
the result 1 is output (logical "true"), as soon as the compari-
son value generally falls below the lower threshold (without condition). Otherwi-
se the output value is 0 (logical "false").
If the limit values are invalidly configured (e.g. upper limit less than lower limit) the result 1
(logical "true") is output on
Output 4
.
The internal data type of this module is Number. If necessary, incoming values are converted
into the internal data type before the comparison (see conversion table below). Thus, observe
the selection of a correct internal data type!