Vega VEGABAR 86, Руководство по эксплуатации

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62
10 Supplement
VEGABAR 86 • Secondary Device for electronic differential pressure
48048-EN-220817
Measuring cell ver-
sion
Measuring cell -
Standard
Measuring cell climate-compensated, depending on measur-
ing range
0.1 % 10 bar, 25 bar 1 bar, 2.5 bar 0.4 bar
Factor FMZ 1 1 2 3
Tab. 17: Determination of the additional factor measuring cell for above example: F
MZ
= 1
Turn Down TD 1 : 1 TD 2.5 : 1 TD 5 : 1 TD 10 : 1 TD 20 : 1
Factor FTD 1 1.75 3 5.5 10.5
Tab. 18: Determination of the additional factor "turn down" for the above example: F
TD
= 1.75
F
T
= F
TBasis
x F
MZ
x F
TD
F
T
= 0.15 % x 1 x 1.75
F
T
= 0.26 %
3. Determination of deviation and long-term stability
The required values for deviation F
Kl
and long-term stability F
stab
are available in the technical data:
Accuracy class Non-linearity, hysteresis and non-repeatability
TD ≤ 5 : 1 TD > 5 : 1
0.1 % < 0.1 % < 0.02 % x TD
Tab. 19: Determination of the deviation from table: F
Kl
= 0.1 %
VEGABAR 86
Time pe-
riod
Measuring cell ø 28 mm Measuring cell
ø 17.5 mm
All measuring ranges Measuring range
0 … +0.025 bar/0 … +2.5 kPa
One year < 0.05 % x TD < 0.1 % x TD < 0.1 % x TD
Five years < 0.1 % x TD < 0.2 % x TD < 0.2 % x TD
Ten years < 0.2 % x TD < 0.4 % x TD < 0.4 % x TD
VEGABAR 87
Time period All measuring ranges Measuring range
0 … +0.025 bar/0 … +2.5 kPa
One year < 0.05 % x TD < 0.1 % x TD
Five years < 0.1 % x TD < 0.2 % x TD
Ten years < 0.2 % x TD < 0.4 % x TD
Tab. 20: Determination of the long-term stability from the table, consideration for one year: F
stab
= 0.05 % x TD =
0.05 % x 2.6 = 0.13 %
4. Calculation of the total deviation - digital signal
- 1. step: Basic accuracy F
perf
F
perf
= √((F
T
)
2
+ (F
Kl
)
2
)