RKI Instruments 65-2432RK-05 - Manual (Page 7)

65-2432RK-05 CO Transmitter • 3
Sensor
The sensor is secured within the sensor housing by the four pins. Through a series of
chemical and electrical reactions, the sensor produces an electrical output that is
proportional to the detector range of the transmitter.
Charcoal Filter
The disc-shaped charcoal filter is secured to face of the CO sensor with a rubber boot. The
charcoal filter prevents interference gases (hydrogen sulfide [H
2
S] and certain
hydrocarbons) from producing false CO readings.
Amplifier
The amplifier converts the electrical output from the sensor to a 4 to 20 mA signal (that is
proportional to the detection range) and transmits the signal to a gas monitoring
controller. The amplifier includes the amplifier type selector, detector terminal strip,
interconnect terminal strip, span pot, zero pot, and test points (see Figure 1).
Amplifier Type Selector
The amplifier type selector is near the bottom left corner of the amplifier. It is to the left of
the detector terminal strip and below the span pot.
The amplifier included with the CO transmitter is designed for use with RKI’s toxic gas
and oxygen transmitters. The amplifier type selector determines for which transmitter the
amplifier is intended. For CO transmitters, a jumper block is installed over the TOXIC
selector (see Figure 1).
Detector Terminal Strip
The detector terminal strip is the four-point terminal strip near the bottom of the
amplifier. Use the detector terminal strip to connect the CO detector to the amplifier.
NOTE: The CO detector is factory-wired to the amplifier. See the Installation section of
this manual for all wiring procedures related to the transmitter.
Interconnect Terminal Strip
The interconnect terminal strip is the four-point terminal strip near the top of the
amplifier. Use the interconnect terminal strip to connect the amplifier to a controller.
Span Pot
The span pot is on the left side of the amplifier. Of the three potentiometers, the span pot
is bottom most. Use the span pot to adjust the transmitter’s response output during the
calibration procedure.
Zero Pot
The zero pot is above the span pot. Use the zero pot to adjust the transmitter’s target gas-
free output during the start-up and calibration procedures.
CAUTION: The third potentiometer is factory-set. Do not adjust it.
Test Points
The test points (labeled TP- and TP+) are on the left and right side of the interconnect
terminal strip. The test points produce a 100 to 500 mV output that is proportional to the
transmitter’s 4 to 20 mA output. Use the test points and a voltmeter to measure the