Appendix D: Correction Factors For Thermoanemometers To Actual Conditions - Alnor APM 151 Manual Del Usario

The downloaded data will now appear in the
application. Now you are able to save the data.
5. From the File menu, choose Save As.
6. Enter the filename under which you will store
the data.
7. Choose the OK key.
Serial Communication Through
Windows 95
• Click on Hyperterminal.exe located in the
accessories menu.
• If a box comes up requesting modem installation,
click No.
• Enter a name (TSI) and choose an icon for meter
downloading to the PC, click OK.
• Connect using Com1 connection, click OK.
CORRECTION FACTORS FOR THERMO-ANEMOMETERS
Velocity is generally expressed in one of two
ways: actual (true) velocity or standard velocity.
Actual velocity is the average speed at which the
molecules are traveling. Standard velocity is
referenced to standard conditions and is equal to
the actual velocity of the air only when the air is at
standard density. The calibration facilities at TSI
Incorporated adjust the actual velocity so that the
same number of molecules per unit time is passing
over the heated elements as if the density were
standard density. This makes the instruments
display standard velocity.
To correct the standard velocity to actual velocity
use the equation below.
V = V x CF
a std
V = Actual velocity
a
19
APPENDIX D:
TO ACTUAL CONDITIONS
• Set port settings under Com1 Properties to
1200BPS, 8 data bits, no parity, stop bits 1, and
Flow Control to None, click OK.
• Click File and choose Properties.
• Click on Settings, choose ASCII set up. Verify
checkmark for Terminal Keys, Emulation to
Auto Detect, and Backscroll Buffer Lines to
500.
• Place a check mark under ASCII Receiving in
the boxes marked Append Line Feeds
• To Incoming Line Ends and Wrap Lines That
Exceed Terminal Width, click OK.
• Click OK again to exit Properties.
• Hyperterminal is now ready to receive
information from the meter.
• Save terminal configuration for future use.
V = Standard Velocity (this is displayed
std
by the instrument)
ρ
= Standard density 0.075 lb/ft
std
and 29.92 in Hg)
ρ
= Actual density in lb/ft
a
= ρ / ρ
CF (Correction Factor)
std a
For your convenience we have made a chart for
determining the correction factor given
temperature and pressure.
Note: The atmospheric pressure as reported by
the National Weather Service is corrected
to sea level and can not be used if
measurements are not at sea level.
For more information on calculating local air
density, call customer service at TSI.
3
(at 70°F
3
19