SICK FLOWSIC600, Техническая информация, Страница: 23 / 262

Product Description
FLOWSIC600 · Technical Information · 8010125 V 4.0 · © SICK AG 23
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Mean path velocity
The most recent 100 measured results (path velocity and measurement status) are stored
in a mean value memory. If no valid path velocity was determined due to a negative
plausibility check, such condition is also stored in the mean value memory. The mean
value memory is organized as FIFO memory. This means that the most recent entry always
overwrites the oldest one. The mean path velocity v
avg i
comprises all valid measured
values stored in the memory.
The percentage of invalid measurements within the last 100 measurements is used as a
quality parameter (Reg. #3008 to #3011 "% Error i"). If the proportion of invalid measure-
ments exceeds a certain threshold (Reg. #3514 "Limit%Error", manufacturer constant =
95%), the path is not used in the calculation of the flow velocity. In such cases, a replace-
ment value may be determined for the faulty path in order to compensate for the failure
(

2.4 , p.28).
Flow velocity (VOG)
The sum of the weighted average of the each of the four path velocities is the flow velocity
through the meter body VA (Reg. #7004 "AvgVelGas").
If the diameter of the meter is not the same as the diameter of the pipe, then VA is calcu-
lated as follows:
In MEPAFLOW600 CBM the reciprocal of the % Error (i.e. % Performance) is
displayed.
v
A:
Flow velocity
w
i
: Weighting factor
of a:
-measuring path
-Reg. #7120 to
#7123 "Weight i"
v
A:
Flow velocity
D
pipe
:Pipe diameter
(Reg. #7119)
Q
V:
Uncorrected
volume flow
rate

pg. 24, 2.3.2
N
valid
v
avg i
=
all valid values
v
Path i

i = 1
4
v
A
= w
i
·
v
avg i

Q
V
0.25
•
Pi + D
pipe 2
• 3600
v
A
=
·