RKI Instruments 65-2340RK - Manual (Page 8)

4 • 65-2340RK Toxic Gas Transmitter
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, zero pot, span pot, and test points (see Figure 1).
Controller Terminal Strip
The controller terminal strip is a two position plug-in style terminal strip located at the
top edge of the amplifier. Use the controller terminal strip to wire the 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. Two of the positions are for use with an oxygen sensor and are
not used in the toxic gas transmitter. Use the two detector terminal strip positions that are
labelled “TOXIC” to connect the detector to the amplifier.
NOTE: The detector is factory-wired to the detector terminal strip. See “Wiring the Toxic
Gas Transmitter to a Controller” on page 6 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
zero (fresh air) output during the start-up and calibration procedures. Turn the adjust-
ment 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 span output and counterclockwise to decrease the span output.
CAUTION: The amplifier includes an additional potentiometer. It is factory-set. Do not adjust it.
Test Points
The test points are on the left side of the amplifier (see Figure 1). The test points produce a
100 mV 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 amplifier’s output during the start-up and
calibration procedures. The black test point in the lower left corner is the negative (-) test
point and the red test point below the zero pot is the positive (+) test point.
Junction Box
Use the junction box to install the transmitter at a mounting site that is remote from the
controller. The junction box protects the amplifier and wiring connections made to the
amplifier. Use the top 3/4 inch conduit hub to connect wiring from the amplifier to the
controller. Use the cover on the front of the junction box to access the interior of the
junction box. The detector and amplifier are factory installed in the junction box. Three
spacers installed on the back of the junction box control the distance of the junction box
from a mounting surface and ensure that there is enough room to install a calibration cup
on the detector during calibration.