Delta OHM DO2003, Руководство пользователя, Страница: 14 / 60

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The measurements provided by the probes are: air speed, air temperature and flow.
Connect the probe to input A and switch on the instrument.
Use the UNIT A key to select the unit of measurement of the value viewed on the top of the display.
The following units are available:
•
For air speed: m/s, km/h, ft/min, mph;
•
For air temperature: °C and °F;
•
For flow: l/s, m
3
/h, cfm.
F
LOW
M
EASUREMENT
The measurement of air flow requires to know the area of the pipe or of the vent perpendicular to
the flow: in the DO2003 programs there are two specific items, “SCT m2“ (SECTION m
2
) and the
corresponding "SCT INC2" (SECTION inch
2
), through which you can configure this parameter
either in m
2
or in inch
2
.
To enter the area, press PROG several times to display either SCT m
2
(area in m
2
) or SCT INC
2
(area in inch
2
), then press ENTER. Use the arrows to set the area value and press ENTER to
confirm.
G
ENERAL
R
EMARKS ON
O
PERATION
By moving the probe inside a stream, speed and flow can change both their position in the space
(from a point to another) and their performance over the time (in the same position, but in
subsequent moments): this is particularly true when the involved area is quite big and when some
turbulences are generated in front of a ventilating grill or a diffuser. The DO2003 provides some
solutions to get a correct measurement even before these elements of disturbance.
1) Space Average ( Duct calc Function)
It is always suggested to record more measurements in different positions and to consider as
valid data only average values. Through the
Duct Calc function (subfunction of UNIT B key),
the DO2003 can record several measurements and provide the relating minimum, maximum and
average value. In particular, the average value is the most important one in this kind of
measurements.
Procedure:
Press UNIT A to select the variable of which you want to get the maximum, minimum and
average value.
Then press PROG >> UNIT B to activate the DUCT CALC function: the display upper line will
show the instant value of the selected variable (speed, flow or temperature), while the lower line
will indicate the number of measured points (at the beginning the value will be 0 because, every
time DUCT CALC is started, the values of previous measurements will be deleted). Place the
probe in the first point to be measured and press MEM to record the first value/point. Repeat
this operation for all the other points to be measured and press MEM every time you want to get
a measurement: the indicator will provide the number of recorded samples. While recording, or
after recording, press Max-Min-Avg Call: the max, min and average values of the selected
quantity will be viewed.
To quit this function, press ESC (REL key).
In general, the bigger the number of recorded measurements is, the higher the accuracy of the
results will be.