Pilz PSSu E S 4AI U - Manual (Page 23)

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4-7
4.2 Configuration
4 Function description
4.2.1.5 Example calculation
Example calculation 4- ][Funktionsbeschreibung_BA_Konfig Skalier Bsp Ein-U
Task:
When there is 10 V at the input, the PII should show a decimal value of
10 000. User scaling (Gain a
2
) should be used in this case. Manufacturer
scaling should not be changed. All numbers are decimals.
Solution:
Manufacturer scaling
y = (a
1
/ 1024 * x) + b
1
and user scaling
y = (a
2
/ 256 * x) + b
2
act consecutively, giving:
y = (a
2
/ 256 * ((a
1
/ 1024 * x) + b
1
)) + b
2
or:
y = (a
1
* a
2
* x / 262144) + (a
2
* b
1
/ 256) + b
2
With default values for a
1
= 8194, b
1
= 0 and the default value b
2
= 0:
y = a
2
/ 32 * x
a
2
= y * 32 / x
Due to the hardware calibration the converter's input range is divided so
that the 10 V end point is assigned the value x = 4095. With the default
values x = 4095 and y= 10 000 the result is:
Gain a
2
= 78