Model 408 NO Calibration Source Manual Rev. D-3
7
4.
OPERATION
To operate the Nitric Oxide Calibration Source
, connect it to an external power
source and turn the instrument on by flipping the back panel on/off switch (see Section
6, Figure 6.2). The instrument requires a 12 V DC source which is supplied by the
110-240 V AC power adapter (2.5 amp) provided. Do not use any other power
adapter.
Once turned on, the instrument will briefly display the version number of the software
installed on the microprocessor. The instrument will then display
Warming up …
delT = -xx.x
where
delT
is the deviation of the temperature of the photolysis chamber from the set
point of 310 K (37°C). As the chamber warms up, the temperature deviation will be
continuously displayed. During the warm up period, the photolysis lamp is turned off.
Once
delT
is within 1°C of the set point, the display will briefly read
Temperature Set
followed by a brief display of:
Set N2O Flow
This will be followed by a prompt to open the regulator of the N
2
O cartridge and set
the flow rate:
Target=60 +/-10
N2O Flow = xx.x
where xx.x is the measured N
2
O flow rate. At this point turn the black knob on the
N
2
O regulator until the measured flow is ~60 mL/min. Once the flow is in range, press
the black Select Switch on the front panel of the instrument. When the menu appears,
release the Select Switch. (Note: You may enter the menu without waiting for the
warm up to be complete and without setting the N
2
O flow rate; however, the NO
concentration selected will not be accurately output unless the NO flow is in the
appropriate range and the set point temperature is reached.) The main menu will be
displayed as:
Menu
200 1000 Flw Adv
Rotating the Select Switch will move the blinking cursor to highlight the first character
of each of the four submenus,
200
,
1000
,
Flw
and
Adv
. One can enter any one of
these submenus by rotating the Select Switch to move the blinking cursor over the
first letter of the submenu and then momentarily pressing
(“clicking”) the Select
Switch. Selecting either
200
or
1000
will have the 408 output NO concentrations of
200 ppb or 1000 ppb respectively.
