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Because the internal real-time clock of an xLogic is backed up, it continues operation after a
power failure. The ambient temperature influences the backup time. At an ambient temperature
of 25°C, the typical backup time of standard/economic ELC-18 is 10 hours ; standard
ELC-12&upgraded ELC-18 is 100 hours;ELC-6&economy ELC-12 is 72 hours.
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4.3.4
.3.4 .3.4
.3.4 Retentivity
Retentivity Retentivity
Retentivity
The switching states and counter values of SFs can be set retentive. This means that current data
are retained after a power failure, and that the block resumes operation at the break point. The
timer is not reset, but resumes operation until the time-to-go has expired, for example, to
enable this response, however, the relevant functions must be set retentive.
R: The data is retained.
/: Current data is not retained (default). See the section in topic "Second circuit program
" on enabling and disabling retentivity.
SFs hours counter, weekly timer, yearly timer and PI controller are always retentive.
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4.3.5
.3.5 .3.5
.3.5 Parameter
Parameter Parameter
Parameter protection
protection protection
protection
In the parameter protection settings, you can determine whether or not the parameters can
be displayed and edited in xLogic parameter assignment mode. Two options are available:
+: The parameter attribute permits read/write access in parameter assignment mode
(default).
-: The parameter settings are read–/write–protected in parameter assignment mode, and can
be edited only in programming mode. See the parameter protection mode example in the "Second
circuit program".
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4 4.3.6
.3.6
.3.6 .3.6 Calculating
Calculating
Calculating Calculating the
the
the the gain
gain
gain gain and
and
and and offset
offset
offset offset of
of
of of analog
analog
analog analog values
values
values values
A sensor is connected to the analog input and converts a process variable into an electrical
signal. This value of sig
nal lies within the typical range of this sensor. xLogic always converts
the electrical signals at the analog input into digital values from 0 to 1000. A voltage of 0 to 10
V at input AI is transformed internally into range of values from 0 to 1000. An input voltage
ex
ceeding 10 V is shown as internal value 1000.
Because you can not always process the range of values from 0 to 1000 as predetermined by
xLogic, you can multi
ply the digital values by a gain factor and then shift the zero of the
range of values (offset). This allows you to output an analog value to the xLogic display, which
is proportional to the actual process variable.
Parameter Parameter Parameter Parameter Minimum Minimum Minimum Minimum Maximum Maximum Maximum Maximum
Input voltage (in V) 0 ≥ ≥ ≥ ≥ 10
Internal value 0 1000
Gain –10.00 +10.00
Offset –10000 +10000
Mathematical Mathematical Mathematical Mathematical rule rule rule rule
Actual value Ax Ax Ax Ax =
(internal value at input Ax∙gain) + offset
Gain Gain Gain Gain and and and and offset offset offset offset calculation calculation calculation calculation
The gain and offset is calculated based on the relevant high
and low values of the function.
Example Example Example Example 1: 1: 1: 1:
The available thermocouples have the following technical