User’s Manual xLogic SuperRelay
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3.3.5 Parameter protection
In the parameter protection settings, you can determine whether the
parameters can be displayed and edited in xLogic parameter modify mode
or not.
3.3.6 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 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 can not 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 Minimum Maximum
Input voltage (in V) 0 ≥ 10
Internal value 0 1000
Gain –10.00 +10.00
Offset –10000 +10000
Mathematical rule
Actual value Ax =
(internal value at input Ax
∙gain) + offset
Gain and offset calculation
The gain and offset is calculated based on the relevant high
and low values of the function.
Example 1:
The available thermocouples have the following technical
data: –30 to +70
, 0 to 10 V DC (i.e. 0 to 1000 in xLogic).
Actual value = (internal value ∙gain) + offset, thus
–30 = (0
∙A) + B, i.e. offset B = –30
+70 = (1000
∙A) –30, i.e. gain A = 0.1
Example 2:
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