RKI Instruments 65-2391RK User Manual
Page 7
65-2391RK CO
2
Transmitter • 3
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.
The amplifier includes the interconnect terminal strip, span potentiometer, zero
potentiometer, and test points (see Figure 1).
Interconnect Terminal Strip
The interconnect terminal strip is a seven-point terminal strip. Use the interconnect
terminal strip to connect the IR CO
2
detector to the amplifier and the amplifier to a
controller.
NOTE:
The IR CO
2
detector is factory-wired to the amplifier. See the Installation section
of this manual for all wiring procedures related to the transmitter.
Span Potentiometer
The span potentiometer is near the bottom of the amplifier (see Figure 1). Use the span
potentiometer to adjust the transmitter’s response output during the calibration
procedure. Turn the adjustment screw clockwise to increase the gas response and
counterclockwise to decrease the gas response.
Zero Potentiometer
The zero potentiometer is to the right of the span potentiometer (see Figure 1). Use the
zero potentiometer to adjust the transmitter’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.
CAUTION:
The amplifier includes two additional potentiometers. They are factory-set. Do not
adjust them.
Test Points
The test points (labeled TP+ and TP-) are to the left of the interconnect terminal strip
(see Figure 1). The test points produce a 100 to 500 mV output that corresponds to the
transmitter’s 4 to 20 mA output. Use the test points and a voltmeter to measure the
transmitter’s output during the start-up and calibration procedures.
Table 2: CO
2
Detector Color Designations
Detector
Color Designations
0 - 5,000 ppm
black shrink tubing on white 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