65-2396RKSS CO
2
Transmitter • 7
To distinguish the different ranges of CO
2
detectors from one another, a short length of shrink tubing is
applied to the wiring where it comes out of the nipple. The following table indicates the color of the
shrink tubing and the color of the wire to which it is applied.
Amplifier
The amplifier converts the electrical output from the detector to a 4 to 20 mA signal that corresponds
to the detection range and transmits the signal to a gas monitoring controller. A foam gasket that
orients the amplifier and keeps it from rotating is installed on the bottom of the amplifier. The
amplifier includes the detector terminal strip, controller terminal strip, span pot, zero pot, and test
points (see Figure 1).
Controller Terminal Strip
The controller terminal strip is a three position plug-in style terminal strip located near the top of the
amplifier. Use the controller terminal strip to wire the CO
2
transmitter to a controller.
Detector Terminal Strip
The detector terminal strip is a four position plug-in style terminal strip located below the controller
terminal strip. Use the detector terminal strip to connect the CO
2
detector to the amplifier.
NOTE:
The IR CO
2
detector is factory-wired to the detector terminal strip. See “Wiring the CO
Transmitter to a Controller” on page 9 for all wiring procedures related to the transmitter.
Zero Pot
The zero pot is located in the upper left corner of the amplifier (see Figure 1). Use a small flat blade
screwdriver to turn the zero pot’s adjustment screw and adjust the amplifier’s target gas-free output
during the start-up and calibration procedures. Turn the adjustment screw clockwise to increase the
zero output and counterclockwise to decrease the zero output.
Span Pot
The span pot is located to the right of the zero pot (see Figure 1). Use a small flat blade screwdriver to
turn the span pot’s adjustment screw and adjust the amplifier’s gas response output during the
calibration procedure. Turn the adjustment screw clockwise to increase the gas response and
counterclockwise to decrease the gas response.
Table 2:CO
2
Detector Color Designations
Detector
Color Designations
0 - 5,000 ppm
black shrink tubing on white wire
0 - 9,000 ppm
white shrink tubing on red wire
0 - 5% volume
green shrink tubing on white wire
0 - 50% volume
green shrink tubing on red wire
0 - 100% volume
red shrink tubing on green wire
