Vega VEGABAR 82, Руководство по эксплуатации

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80
11 Supplement
VEGABAR 82 • Profibus PA
45031-EN-220624
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)
All process fittings Process fitting G½
(ISO 228-1)
One year < 0.05 % x TD < 0.1 % x TD < 0.1 % x TD < 0.25 % x TD
Five years < 0.1 % x TD < 0.2 % x TD < 0.2 % x TD < 0.5 % x TD
Ten years < 0.2 % x TD < 0.4 % x TD < 0.4 % x TD < 1 % x TD
Tab. 32: Determination of the long-term stability from the table, consideration for one year: F
stab
= 0.05 % x TD
4. Calculation of the total deviation - digital signal outputs
1. step: Basic deviation F
perf
F
perf
= √((F
T
)
2
+ (F
Kl
)
2
)
F
T
= 0.79 %
F
Kl
= 0.2 %
F
perf
= √(0.79 %)
2
+ (0.2 %)
2
)
F
perf
= 0.81 %
2. step: Total deviation F
total
F
total
= F
perf
+ F
stab
F
perf
= 0.81 % (result of step 1)
F
stab
= (0.05 % x TD)
F
stab
= (0.05 % x 2.5)
F
stab
= 0.125 %
F
total
= 0.81 % + 0.125 % = 0.94 %
The total deviation of the measurement is hence 0.94 %.
Deviation in bar: 0.94 % of 4 bar = 0.038 bar
The example shows that the measurement error in practice can be considerably higher than the
basic deviation. Reasons are temperature influence and Turn down.
11.5 Dimensions
The following dimensional drawings represent only an extract of the possible versions. Detailed
dimensional drawings can be downloaded at www.vega.com under " Downloads " and " Drawings ".