8
.
3
C
alculation of total deviation
(
similar to
DIN
16086
)
T
he 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
K
l
)
2
)
W
ith analogue output
,
the error of the current output
F
a
is also added
.
F
perf
= √
((
F
T
)
2
+
(
F
K
l
)
2
+
(
F
a
)
2
)
W
ith
:
l
F
total
:
T
otal deviation
l
F
perf
:
B
asic accuracy
l
F
stab
:
L
ong
-
term drift
l
F
T
:
T
emperature coe
ffi
cient
(
in
fl
uence of medium or ambient
temperature
)
l
F
K
l
:
D
eviation
l
F
a
:
E
rror current output
P
ressure measurement in the pipeline
8
bar
(
800
KP
a
)
P
roduct temperature
50
°
C
,
hence within the compensated range
VEGABAR
64
with measuring range
25
bar
C
alculation of the set
T
urn
D
own
:
TD
=
10
bar
/
8
bar
,
TD
=
1
.
25
B
asic accuracy digital output signal in percent
:
F
perf
= √
((
F
T
)
2
+
(
F
K
l
)
2
)
F
T
=
(
0
.
05
% +
0
.
1
%
x
TD
)
F
K
l
=
0
.
075
%
F
perf
= √
((
0
.
05
% +
0
.
1
%
x
1
.
25
)
2
+
(
0
.
075
%
)
2
)
F
perf
=
0
.
19
%
T
otal deviation digital output signal in percent
:
F
total
=
F
perf
+
F
stab
F
stab
=
(
0
.
1
%
x
TD
)/
year
F
stab
=
(
0
.
1
%
x
1
.
25
)/
year
F
stab
=
0
.
125
%
F
total
=
0
.
19
% +
0
.
125
% =
0
.
315
%
T
otal deviation digital output signal absolute
:
F
total
=
0
.
315
%
x
8
bar
/
100
% =
25
.
2
mbar
T
otal deviation
E
xample
VEGABAR
64
•
F
oundation
F
ieldbus
49
8
M
aintenance and fault recti
fi
cation
28259
-
EN
-
081209