TARGAS-1 Operation Manual V. 1.02
25
3. Connect the sampling tubing to the
AIR IN
port on the back of the TARGAS-1 console.
Remember to make sure the external air filter is fitted to the
AIR IN
port (see External Air Filter on
page 140). This will be your reference air. We strongly recommend that your reference air is as
far away from any local CO
2
disturbances such as people breathing, ventilation, automobiles,
parking lots, etc. This can be as easy as running a long piece of tubing outside the window in
your lab or away from where you are taking measurements in the field. If in the field you could
also use the “
fresh air intake unit
” supplied with the system which will help to provide steady
reference air. It is very important that you establish a very steady reference air supply to ensure
that your system is working properly and to make measurements easier and quicker.
4. Make sure you set the rb value (boundary layer resistance) and RS factor for your cuvette
correctly. Settings associated with rb and RS Factor are located in the Settings 1 menu (press
Main, Settings, RB or RS Fact
). The rb value is measured at the factory and is programmed into
your TARGAS-1 console when supplied as a new instrument. This value is also written on the
“Tested” label on your leaf cuvette for additional reference purposes (See RB Setting on page 54
for more information). The RS Factor is set to 0.50 as default on the assumption that you have
50% stomata on the upper and lower side of your leaf. You should enter the value associated
with your leaf (See RS Factor Setting on page 55 for more information).
5. Make sure the cuvette flow rate
(Flow)
located in the bottom right hand corner of the main
measure display is set to our recommended rate of 250 cc/min. If not, press the
(Flow)
button
and set it to 250. Also make sure that the sample flow rate is set to 150 cc/min (see Sample Flow
Setting on page 63). Settings associated with sample flow are located in the Settings 3 menu
(press
Main, Settings, right arrow, right arrow, Flow
). With the leaf cuvette head closed, all
readings should be stable and you should see something similar to this displayed:
•
Stable CO2r and CO2a at ambient levels (~ 400 ppm)
•
Stable H2Or and H2Oa at ambient levels
•
CO2d should be stable and near 0 (± 1 ppm) and H2Od should also be stable and near 0 (± 0.5
mb)
•
PARe and PARi should be at ambient light levels (Typically less than 50 µmol m
-2
s-
1
indoors)
•
Flow rate should be approximately 250 cc/min
If everything looks similar to the above you should be good to go. Good luck!
