ABB UMC100.3 Manual page 42

42 C U S T O M A P P L I C AT I O N E D I T O R M A N U A L
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Function block reference
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Scale1
This function block allows to scale a word (16 Bit).
Calculation rule: Out = In * X Scale / Y Scale + P Offset – N Offset
O set
If the calculated result is > 65535 the output will be limited to 65535.
If the results is < 0 the output is limited to 0.
Example: User wants to show fill level in liters on the LCD display. Depending on fill level the motor shall be started to refill.
Focus here is only on scaling. The level sensor was wired to an analog input and configured to 4-20mA.
10.000l
20mA
4mA
Solution: Connect In(W) to the analog input channel, set X-scale to 9900, Y-scale to 27648, P Offset to 100, N Offset to 0.
Out = Input * 9900 liters / 27648 + 100 liters
Function Block
Inputs (from top to down)
Output
Parameters
Gradient = X Scale / Y Scale
Gradient
Level Meter
100l
Signal Name
In High Word (W): 16 Bit value to scale
X Scale: Nominator of Gradient
Y Scale: Denominator of Gradient
P Offset: Positive Offset
N Offfset: Negative Offset
Out (W): Results of the scaling operation
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20mA
10000l
Instrument input
4mA
4mA ...
100l
20mA
Analog Scaled to Liters
Value in UMC
0 100l
... ...
27648 10000
Data Type
World
Word
Word
Word
Word
Word