Teledyne LGA-3500 - Laser Gas Analysis system User Manual
Page 46
Operation Model
3500
Teledyne Analytical Instruments
32
In a sequence of the last k current concentration values:
n
n
n
k
n
C
C
C
C
,
,
,.......
1
2
1
−
−
+
−
. The average value of the sequence is:
k
C
C
C
C
n
n
k
n
+
+
+
=
−
+
−
1
1
...
.
The standard deviation of current gas concentration is given by:
1
)
(
)
(
...
)
(
2
2
1
2
1
−
−
+
−
+
+
−
=
−
+
−
k
C
C
C
C
C
C
e
n
n
k
n
n
.
The Model 3500 sets k to 20 by default. For a strictly random
concentration sequence, statistically, different k produces the same
standard deviation.
Note: The 4-20mA output port on the Model 3500 outputs the
average gas concentration value computed with the above
method, the standard deviation at the port is therefore
about
N
1
of the value displayed on the LCD, where, N
is the average times set by the user.
In the MainMenu, there are 5 submenus: Display, System, Cali.,
Com. and Alarm. In the MainMenu, the system only reacts to “SET”,
“<” and “>”. All the other keystrokes are disabled.
Press “SET”—the system enters the submenu selected by the
cursor.
Press “<”—the cursor moves one position left. If the cursor is
already on the leftmost button, the cursor moves to
the rightmost button.
Press “>”—the cursor moves one position right. If the cursor is
already on the rightmost button, the cursor moves to
the leftmost button.
By operating the above keystrokes, you can enter the submenu of
the MainMenu:
• Display: Press “SET”—the system enters the Display menu.
• System: Press “SET”—the system asks for Sys Pwd. If the
password is correct, the system enters the System menu.