Rievtech xLogic ELC Series User Manual page 78

Gain
Offset
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:
A pressure sensor converts a pressure of 1000 mbar into a voltage of 0 V, and a pressure of 5000 mbar into
a voltage of 10 V.
Actual value = (internal value. gain) + offset, thus
= (0·A) + B, i.e. offset B = 1000
=（1000 ∙A) +1000, i.e. gain A = 4
Example of analog values
Process
variable
–30 0 C
0 0 C
+70 0 C
1000 mbar 0
3700 mbar 6.75
5000 mbar 10
–10.00
–10000
Voltage Internal Gain
(V) value
0 0 0.1
3 300 0.1
10 1000 0.1
0 4
675 4
1000 4
0 0 0.01
5 500 0.01
10 1000 0.01
0 0 1
5 500 1
10 1000 1
+10.00
+10000
Offset Value
shown
(Ax)
–30 –30
–30 0
–30 70
1000 1000
1000 3700
1000 5000
0 0
0 5
0 10
0 0
0 500
0 1000
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