Retentivity; Parameter Protection; Calculating The Gain And Offset Of Analog Values - Rievtech xLogic ELC Series User Manual

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 xLogic is 100 hours.

6.4.4 Retentivity

The switching states and counter values of SFs can be set retentive. This means that current data is 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.

5.4.5 Parameter 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".

5.4.6 Calculating the gain and offset of analog values

A sensor is connected to the analog input and converts a process variable into an electrical signal. This
value of signal 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 (or current signal 0/4...20mA)
at input AI is transformed internally into range of values from 0 to 1000. An input voltage exceeding 10
V is shown as internal value 1000.
Because you cannot always process the range of values from 0 to 1000 as predetermined by xLogic, you
can multiply 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
Input voltage (in V)
Input current(in mA)
Internal value
77
Minimum Maximum
≥ 10
0
0/4 ≥20
0 1000