―
124
―
HXPRM10mnCT002E
11.2.2 The Accuracy at the Computation
(1) Scaling
The accuracy rating at the scaling is as following formula.
Scaling accuracy (digits)
＝
Range accuracy rating (digits) × Scaling factor
＋
2 digits
But, Scaling factor
＝
Example 1
）
When VOLT range is
－
1.000
～
1.000V and Scaling range is 0.00
～
100.00.
Range accuracy rating
＝
0.1%×1.000V
＋
3 digits
(Input +1.000V)
＝
4 digits
Scaling factor
＝
＝
5
Therefore, Scaling accuracy
＝±（
4×5
＋
2
）
＝±
22 digits
Analog recording accuracy
＝±
4
＋｛
1000
－（－
1000
）｝×
＝±
10 digits
＝±
0.01V
Example 2
）
When Type K is 0.0
～
200.0
℃
and Scaling is 0.00
～
200.00.
Range accuracy rating
＝
0.15%×200.0
＋
0.3
℃
（
Input 200
℃）
＝
0.6
℃
＝
6 digits
Scaling factor
＝
＝
10
Therefore, Scaling accuracy
＝±（
6×10
＋
2
）
＝±
62 digits
＝±
0.62
℃
(2) Square root computation
The square root computation is as following formula.
Display value
＝
10
Process variable
Display value accuracy rating:
ε
, Process variable accuracy: e, and
Process variable: x (convert into %).
Display value
＝
10
x±e
≒
10
x
±
Therefore, Display value accuracy
εε＝
10000
－
0
1000
－（－
1000
）
0.3
100
20000
－
0
2000
－
0
10e
2
x
5e
x
Scaling span (digits)
Measurement range span (digits)
