WIKA CPT-2x series, Руководство по эксплуатации

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62
9 Supplement
WIKA Operating Instructions - Process pressure transmitter CPT-2x
Measuring cell version
Measuring cell standard, depending on the accuracy class
0.05 %, 0.1 % 0.2 % (0.1 bar
abs
) 0.2 %
Factor FMZ 1 2 3
Tab. 13: Determination of the additional factor measuring cell for above example: F
MZ
= 1
The additional factor FTD through Turn down is calculated according to the following formula:
F
TD
= 0.5 x TD + 0.5, with TD = 8.2:1 of above calculation
F
TD
= 0.5 x 8.2 + 0.5 = 4.6
Determination of the temperature error master sensor for above example:
F
T
= F
TBasis
x F
MZ
x F
TD
F
T
= 0.15 % x 1 x 4.6
F
T
= 0.69 %
The temperature error of each sensor is hence 0.69 %
3. Determination of deviation and long-term stability
Accuracy class Non-linearity, hysteresis and non-repeatability
TD ≤ 5 : 1 TD > 5 : 1
0.05 % < 0.05 % < 0.01 % x TD
0.1 % < 0.1 % < 0.02 % x TD
0.2 % < 0.2 % < 0.04 % x TD
Tab. 14: Determination of the deviation F
Kl
from the table with accuracy class 0.1 %: F
Kl
= 0.02 % x TD =
0.02 % x 8.2 = 0.16 %
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. 15: Determination of the long-term stability F
stab
from the table, consideration for one year: F
stab
= 0.05 % x TD
= 0.05 % x 8.2 = 0.41 %
4. Calculation of the total deviation
- 1. step: Basic deviation F
perf
F
perf
= √((F
T
)
2
+ (F
Kl
)
2
)
F
T
= 0.69 %
F
Kl
= 0.16 % (calculation of above table)
F
perf
= √(0.69 %)
2
+ (0.16 %)
2
)
F
perf
= 0.71 %
- 2. step: Total deviation F
total
F
total
= F
perf
+ F
stab