RKI Instruments 65-2461RK - Manual (Page 7)

65-2461RK PPM Hexane Transmitter • 3
amplifier (see below).
Amplifier
The amplifier converts the non-linear electrical output from the detector to a linear 4 to 20
mA signal that corresponds to the detection range and transmits the signal to a gas
monitoring controller. The amplifier includes the terminal strips, gas select jumper strip,
span pot, zero pot, load voltage pot, and test points (see Figure 1).
Controller Terminal Strip
The controller terminal strip is a three position plug-in style terminal strip located near the
top of the amplifier. Use the controller terminal strip to wire the transmitter to a controller.
Detector Terminal Strip
The detector terminal strip is a three position plug-in style terminal strip located below
the controller terminal strip. Use the detector terminal strip to connect the detector to the
amplifier.
NOTE: The detector is factory-wired to the detector terminal strip. See “Wiring the PPM
Hexane Transmitter” on page 5 for all wiring procedures related to the
transmitter.
Gas Select Jumper Strip
The gas select jumper strip is a three position pin style terminal strip located in the lower
left corner of the amplifier. A label next to the jumper strip indicates which pins must be
shorted to select hexane or hydrogen. A jumper block is installed at the factory over pins 1
& 2 to select hexane as the gas type. The gas type defines the linearizing curve used by the
amplifier to linearize the detector output.
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.
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.
Load Voltage Pot
The load voltage pot is located below the zero and span pots (see Figure 1). The load
voltage pot is not needed for normal scheduled maintenance, so it is a right angle pot that
is not accessible unless the amplifier is lifted out of the junction box enough to access the
adjustment screw. Use a small flat blade screwdriver to turn the load voltage pot’s
adjustment screw and adjust the amplifier’s detector load voltage when the detector or
amplifier is replaced.
CAUTION: The amplifier includes additional pots. They are factory-set. Do not adjust them.