RKI Instruments Pioneer 4W - Manual (Page 49)

Pioneer Operator’s Manual (PRELIMINARY) Combustible Gas Transmitter • 3
Detector housing
The sensing elements and flame arrestor are installed within the detector housing.
Mounting threads (1/2 in. NPT) at the top of the detector allow you to mount the
combustible gas detector into the bottom conduit hub of the junction box. A rainshield
screws onto the bottom of the detector. The rainshield helps protect the detector from
debris in the monitoring environment.
Detector leads
Four color-coded leads extend from the top of the detector. The leads allow you to connect
the combustible gas detector to the amplifier.
Amplifier
The amplifier converts the electrical output from the detector to a 4 to 20 mA signal (that is
proportional to the detection range) and transmits the signal to the Pioneer. The amplifier
includes the interconnect terminal strip, span potentiometer, zero potentiometer, and test
points (see Figure 1.)
Interconnect terminal strip
The interconnect terminal strip is a seven-point terminal strip. Use the interconnect
terminal strip to connect the combustible gas detector to the amplifier and the amplifier to
the Pioneer Gas Monitor.
NOTE: The combustible gas detector is factory-wired to the amplifier. See the
Installation section of this insert for all wiring procedures related to the
transmitter.
Span potentiometer
The span potentiometer is near the bottom of the amplifier. Of the two potentiometers
near the bottom of the amplifier, the span potentiometer is farthest to the left. Use the span
potentiometer to adjust the transmitter’s response output during the calibration
procedure.
Zero potentiometer
The zero potentiometer is to the right of 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 amplifier includes two additional potentiometers. They are factory-set. Do not
adjust them.
Test points
The test points (labeled TP+ and TP- ) are to the left 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.