RKI Instruments 65-2432RK - Manual (Page 6)

65-2432RK CO Transmitter • 6
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 potentiometer, zero potentiometer, 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 potentiometer.
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 potentiometer
The span potentiometer is on the left side of the amplifier. Of the three potentiometers,
the span potentiometer is bottom most. Use the span potentiometer to adjust the
transmitter’s response output during the calibration procedure.
Zero potentiometer
The zero potentiometer is above the span potentiometer. Use the zero potentiometer 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
transmitter’s output during the start-up and calibration procedures.