Section 3
Operation 3-13
To convert current output (I) to units of ppm CO
2
in your computer or other output device, the
following equation can be used:
CO X X
I
X
FZ Z2
4
16
= −
−
⎛
⎝
⎞
⎠
+()
3-6
where I is the measured current, X
F
is the full scale value for CO
2
output (entered in the
Settings Window as the 2.5 or 5V full scale value, up to 20,000 ppm), and X
Z
is the zero value
entered.
Example: The zero CO
2
value entered is 0 ppm (X
Z
), the full scale CO
2
value entered is 2000
ppm (X
F
), and the measured current output (I) is 16.25 mA. To convert to ppm CO
2
:
CO
2
2000
16 25 4
16
0=
−
⎛
⎝
⎞
⎠
+()
.
3-7
= 1531.25 ppm.
Using the Terminal Strip
The terminal strip is located on the front panel of the LI-820. To connect the wires, insert the
bare wire end into the appropriate terminal and tighten the screw above that terminal using the
small flat head screwdriver in the spare parts kit. The terminal strip can be removed to aid in
connecting the wires by pulling straight out on the face.
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