VEGA VEGABAR 65 Profibus PA User Manual
Page 48
?
E
036
l
no operable sensor software
à Carry out a software update or send the instrument for repair
?
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
65 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)
Reaction after fault rec-
tification
Total deviation
Example
48
VEGABAR
65 • Profibus PA
8 Maintenance and fault rectification
28253
-EN
-090522