ABB RELION REX640 Technical Manual page 170

Section 3
Basic functions
164
AI_VAL
200 °C
Value unit
"Degrees celsius"
-40 °C
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Figure 54: Pt100 scaling function
Scaling example 2
Input mode is set to -20...20 mA that is used for tap position information fed from the
tap changer. The tap positions are between -36...36. Thus, the scaling setting Value
minimum is set to "-36" and Value maximum is set to "36". These settings apply the
input scaling to the output. In the tap position case, the Value unit should be set to
"Dimensionless".
Value maximum AI_VAL
36
Value unit
"Dimensionless"
Value minimum
-36
4 mA
Input minimum
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Figure 55: Tap changer position from mA input
Scaling example 3
When Input mode is set to "Resistance", the output can be scaled as desired. For
example, the desired function output is a ratio in a function of resistance. If the input
resistance varies between 100...1600 ohms, Input minimum is set to "100" and Input
maximum is set to "1600". As the wanted output should be in percents, the setting
Value unit is set to "Dimensionless". When Input mode is set to "Resistance", output
scaling is enabled. Thus, Value minimum is set to "0" and Value maximum is set to
Input mode
"Pt100"
Input mode
"-20..20mA"
Input maximum
Technical Manual
1MRS759142 C
Input
Input
20 mA
REX640