VEGA VEGABAR 64 Profibus PA User Manual
Page 48
?
E
041
l
Hardware error, electronics defective
à Exchange instrument or return instrument for repair
?
E
113
l
Communication conflict
à Exchange instrument or return instrument for repair
Depending on the failure reason and measures taken, the steps
described in chapter "Set up" must be carried out again, if necessary.
8.3 Calculation of total deviation (similar to
DIN 16086)
The total deviation F
total
according to DIN 16086 is the sum of basic
accuracy F
perf
and longterm stability F
stab
. F
total
is also called
maximum practical deviation or utility error.
F
total
= F
perf
+ F
stab
F
perf
= √((F
T
)
2
+ (F
Kl
)
2
)
With analogue output, the error of the current output F
a
is also added.
F
perf
= √((F
T
)
2
+ (F
Kl
)
2
+ (F
a
)
2
)
With:
l
F
total
: Total deviation
l
F
perf
: Basic accuracy
l
F
stab
: Long-term drift
l
F
T
: Temperature coefficient (influence of medium or ambient
temperature)
l
F
Kl
: Deviation
l
F
a
: Error current output
Pressure measurement in the pipeline 8 bar (800 KPa)
Product temperature 50 °C, hence within the compensated range
VEGABAR
64 with measuring range 25 bar
Calculation of the set Turn Down: TD = 10 bar/8 bar, TD = 1.25
Basic accuracy digital output signal in percent:
F
perf
= √((F
T
)
2
+ (F
Kl
)
2
)
F
T
= (0.05 % + 0.1 % x TD)
F
Kl
=
0.075 %
F
perf
= √((0.05 % + 0.1 % x 1.25)
2
+ (0.075 %)
2
)
F
perf
=
0.19 %
Reaction after fault rec-
tification
Total deviation
Example
48
VEGABAR
64 • Profibus PA
8 Maintenance and fault rectification
28252
-EN
-081209