Siemens SIPART DR24 - Page 62

1 Technical Description
1.5 Functional Description
1.5.8 Complex Functions (Arithmetic blocks c, d, h)
Manual
60
SIP ART DR24 6DR2410
C79000-G7476-C153-03
Related to the correction factor it follows:
A = Δp

·f(E2,E3)

with F = f(E2, E3)

=
(PE − PA) E2 + PA
(tE − tA) E3 + tA

The measuring ranges are normalized to the calculation state with the parameters PA, PE, tA,
tE (correction quotients start/end for pressure and temperature).
Mass flow computer, qm
A=q
m
,E2=p,E3=Â
PA =
P
absA
P
B
,PE=
P
absE
P
B
,
tA =
T
A
T
B
,tE=
T
E
T
B
with T
A∕E∕B
[K]
Volume flow computer related to the operating status q
V
Since the volume is reciprocally proportional to the density, a volume flow computer can be
made out of this mass flow computer by changing the inputs E2 and E3.
A=q
v
,E2=Â,E3=p
PA =
T
A
T
B
,PE=
T
E
T
B
with T
A∕E∕B
[K],
tA =
P
absA
P
B
,tE=
P
absE
P
B
Volume flow computer related to the standard status q
VN
Since the output signal is now related to the volume flow in the standard status, T
N
= 273.15 K,
P
N
= 1.01325 bar
abs
and no longer to the operating state, it must be corrected accordingly.
A=q
VN
,E2=p,E3=Â
PA =
P
absA
P
B
,PE=
P
absE
P
B
tA =
T
A
T
B
,tE=
T
E
T
B
with T
A∕E∕B
[K],
The following applies for all computers:
p
absA
to p
absE
T ransmitter range absolute pressure (bar)
T
A
to T
E
T ransmitter range absolute temperature (K)
is formed from the transmitter range Â
A
to Â
E
by conversion:
T(K) = 273, 15 + Â (_C)