61
9 Supplement
WIKA Operating Instructions - Process pressure transmitter IPT-2x
Accuracy class
In the compensated temperature range of 10 … +70 °C
0.075 %, 0.1 %
0.2 %
Factor FMZ
1
3
Tab. 19: 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
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
0.075 %
< 0.075 %
< 0.015 % x TD
0.1 %
< 0.1 %
< 0.02 % x TD
0.2 %
< 0.2 %
< 0.04 % x TD
Tab. 20: Determination of the deviation from the table: F
Kl
= 0.02 % x TD = 0.02 % x 8.2 = 0.16 %
Version
Measuring ranges > 1 bar
< 0.1 % x TD/year
Measuring ranges > 1 bar, isolating liquid, synthetic oil,
diaphragm Elgiloy (2.4711)
< 0.15 % x TD/year
Measuring range 1 bar
< 0.15 % x TD/year
Measuring range 0.4 bar
< 0.35 % x TD/year
Determination of the long-term stability from the table, consideration for one year: F
stab
= 0.1 % x 8.2
= 0.82 %
4. Calculation of the total deviation
- 1. step: Basic accuracy 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
