Model 408 NO Calibration Source Manual Rev. D-3
8
4.1
Flw (Flow Menu)
Choosing the Flw menu allows one to continuously view the air flow rate (Air) and N
2
O
Flow rate (N2O). The flow rates are displayed on the LCD in VOLUMETRIC FLOW
units (cc/min), for example, as follows:
Air = 3012 cc/min
N2O = 65.7 cc/min
This menu may be used to adjust the air flow rate using the recessed needle valve in
the back of the instrument as described below, and the N
2
O flow rate using the N
2
O
regulator valve.
4.2
Adv (Advanced Menu)
Selecting
Adv
will access the advanced menu and the LCD will display:
Cfg NO Zer
4.2.1 Cfg (Configuration Menu)
Selecting the
Cfg
menu will produce the following display:
Cfg Menu
Err Prg Run
The purpose of the return symbol (
) is to return to the previous menu; i.e.,
depressing the Select Switch when
is highlighted allows one to move one level up
in the menu.
Err
is a submenu for displaying error code definitions across the LCD. The user can
scroll through the error code definitions by rotating the Select Switch. The list of error
codes and definitions can be found in Section 4.7 of this manual below.
Prg
is a submenu for defining a programmed series of step NO concentrations.
Choosing
Prg
results in the following submenu:
Prg Menu
Num Steps= x
Note:
In order to obtain accurate results, the air flow rate may need to be adjusted
to 3.0 L/min (3000 cc/min) when first used. This is because the air flow was set at
an altitude of 1.6 km at the factory, and the air pump may produce a different flow
rate at other altitudes. The instrument compensates for variations in flow rate, but
for best results the flow should be as close to 3.0 L/min as possible. To set the air
flow rate, enter the
Cfg/Flw
submenu and use a flathead screwdriver to adjust the
air flow needle valve on the back of the instrument until the flow reads close to 3.0
L/min. Rotating the valve clockwise increases the air flow rate, and counter
clockwise decreases the flow rate.
