Vega VEGABAR 86 Operating Instructions Manual page 67

Turn Down TD 1 : 1
Factor FTD 1
Tab. 24: Determination of the additional factor "turn down" for the above example: F
Turn Down TD 1 : 1
Factor FTD 1
Tab. 25: Determination of the additional factor "turn down" for the above example: F
F = F x F x F
T TBasis MZ TD
F = 0.15 % x 1 x 1.75
T
F = 0.26 %
T
3. Determination of deviation and long-term stability
The required values for deviation F
Accuracy class
0.1 %
Tab. 26: Determination of the deviation from table: F
VEGABAR 86
Time pe-
riod
All measuring ranges
One year < 0.05 % x TD
Five years < 0.1 % x TD
Ten years < 0.2 % x TD
VEGABAR 87
Time period
One year
Five years
Ten years
Tab. 27: Determination of the long-term stability from the table, consideration for one year: F
0.05 % x 2.6 = 0.13 %
4. Calculation of the total deviation - digital signal
- 1. step: Basic accuracy F
F = √((F ) + (F ) )
2 2
perf T Kl
F = 0.26 %
T
F = 0.1 %
Kl
VEGABAR 86 • Foundation Fieldbus
TD 2.5 : 1
1.75
TD 2.5 : 1
1.75
and long-term stability F
Kl
Non-linearity, hysteresis and non-repeatability
TD ≤ 5 : 1
< 0.1 %
= 0.1 %
Kl
Measuring cell ø 28 mm
Measuring range
0 ... +0.025 bar/0 ... +2.5 kPa
< 0.1 % x TD
< 0.2 % x TD
< 0.4 % x TD
All measuring ranges
< 0.05 % x TD
< 0.1 % x TD
< 0.2 % x TD
perf
TD 5 : 1 TD 10 : 1
3 5.5
TD 5 : 1 TD 10 : 1
3 5.5
are available in the technical data:
stab
TD > 5 : 1
< 0.02 % x TD
Measuring range
0 ... +0.025 bar/0 ... +2.5 kPa
< 0.1 % x TD
< 0.2 % x TD
< 0.4 % x TD
11 Supplement
TD 20 : 1
10.5
= 1.75
TD
TD 20 : 1
10.5
= 1.75
TD
Measuring cell
ø 17.5 mm
< 0.1 % x TD
< 0.2 % x TD
< 0.4 % x TD
= 0.05 % x TD =
stab
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