12. Function menus
40
Program the cycle (see 12.5.5) and set
cycle timer : 00:15:00 Un
To set memory activation, output format :
<MON/MOFF>
,
<FORM>
Start measuring operation, averaging runs :
<START>
Verification :
»
Stop measuring operation :
<STOP>
The average value of the last cycle can be read out :
average value : 13.24 mls
The average value is also output or saved in function
channel M32/33/34 with the range M(t).
12.2.5
Averaging over measuring points
The average value can also be determined over a
number of associated measuring points. In menu
average value over measuring points
you can set
the start channel (Bk2) with the measuring point in the
1st row and having selected the function
to channel :
also the end channel (Bk1). The average value M(n)
is programmed automatically to function channel
M32/33/34 (see13.9). Measuring point scanning is
continuous (see 12.5.8.4).
Average value M(n) from M01 (Bk2) to M03 (Bk1) :
12.2.6
Volume flow measurement
To determine volume flow VF
in flow channels the average flow velocity must
be
v̅
multiplied by the cross-section area CS :
VF =
v̅
. CS
. 0.36
VF = m
3
/h,
v̅
= m/s, CS = cm
2
With Pitot tubes, to calculate the actual velocity in the sensor display,
tempera-
ture compensation and atmospheric pressure compensation
are provided
(see 11.2.4, 11.2.5).
To acquire the average flow velocity
v̅
there are the following possibilities :
1.
Averaging over individual measuring operations
(see 12.2.2)
2.
Averaging over time
(see 12.2.3)
For rough air volume measurements at air vents and gratings apply the flow
sensor at one end, start averaging, and proceed uniformly over the whole
cross-section; on reaching the other end of the cross-section stop averaging.
3.
Networked measuring as per VDE
(see 12.2.7)
If the average value is assigned m/s as units,
it is
possible, for the purposes of determining the
volume flow,
to call up
the volume flow menu
di
