RKI Instruments 65-2422RK-05 - Manual (Page 8)

4 • 65-2422RK-05 H
2
S Transmitter
chemical and electrical reactions, the sensor produces an electrical output that is
proportional to the detector range of the transmitter.
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 potentiometer.
The amplifier included with the H
2
S 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 H
2
S 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 H
2
S detector to the amplifier.
NOTE: The H
2
S 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
transmitter’s output during the start-up and calibration procedures.
Junction Box
Use the junction box to install the H
2
S transmitter at a mounting site that is remote from
the controller. The junction box also protects the amplifier and wiring connections made
to the amplifier. Use the two 3/4 in. conduit hubs to mount the detector to the junction
box (bottom hub) and connect wiring from the amplifier to the controller (top hub).