RKI Instruments 65-2451RK-04 - Manual (Page 8)

4 • 65-2451RK-04 Hydrogen Transmitter
response output during the calibration procedure. Turn the adjustment screw clockwise to
increase the gas response and counterclockwise to decrease the gas response.
CAUTION: The amplifier includes two additional potentiometers. They are factory-set. Do not
adjust them.
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.
Amplifier Junction Box
The amplifier junction box protects the amplifier and wiring connections made to the
amplifier. Use the top 3/4’’ conduit hub to connect wiring from the amplifier to the
controller. Use the bottom 3/4” conduit hub to wire the remotely installed hydrogen
detector. Use the cover on the front of the junction box to access the interior of the junction
box. The amplifier is factory installed in the junction box. Three spacers installed on the
back of the junction box controls the distance of the junction box from a mounting surface.
Detector Junction Box
The detector junction box is intended to be installed remotely from the amplifier junction
box. The hydrogen detector is factory installed in the bottom 3/4” conduit hub. A
terminal strip is provided for wiring connections and the detector is factory wired to one
side of this terminal strip. The other side of the terminal strip is for user-supplied wiring
to the detector terminal strip located in the amplifier junction box. This wiring should go
through the top 3/4” conduit hub. Three spacers installed on the back of the junction box
controls the distance of the junction box from a mounting surface.
Installation
This section describes procedures to mount the hydrogen transmitter in the monitoring
environment and wire the transmitter to a controller.
Mounting the Hydrogen Transmitter
1. Select a mounting site that is representative of the monitoring environment. Consider
the following when you select the mounting site.
• For the amplifier junction box, select a site where the junction box is not likely to
be bumped or disturbed. Make sure there is sufficient room to perform start-up,
maintenance, and calibration procedures. The site should be easily accessible.
• For the detector junction box, select a site where the target gas is likely to be found
first. For hydrogen, which is lighter than air, mount the transmitter near the ceil-
ing or where hydrogen is most likely to accumulate.
• The junction boxes should be mounted no further than 200 feet from each other.