RKI Instruments 35-3000RKA-LEL - Manual (Page 5)

Sample Draw Combustible Gas Detector • 5
Connector
The top of the sensor includes five pins that plug into the socket connector. This connector
allows you to replace the sensor without disconnecting the wiring. The sensor leads are
soldered to the connector.
Sensor leads
Four color-coded leads extend from the connector. The leads allow you to connect the
combustible gas sensor to the main circuit board.
Transmitter
The transmitter is mounted to the left of the combustible sensor. It consists of the span
pot, zero pot, transmitter interconnect terminal strip, sensor terminal strip and test points.
Span/zero pots
The span and zero pots are located at the bottom edge of the transmitter and are used for
calibration. Use the span pot to make adjustments to gas response readings and the zero
pot to make adjustments to the zero reading
Transmitter interconnect terminal strip
The transmitter interconnect terminal strip is the six-point terminal strip near the right
edge of the transmitter. The transmitter is factory wired to the sensor and main circuit
board.
Test points
The test points are located on the left side of the transmitter and are labeled TP+ and TP- .
A 100 mV - 500 mV output is available at these testpoints for use during calibration.
Main Circuit Board
The main circuit board includes the interconnect terminal strip, transmitter terminal strip,
pump terminal strip, and relay (see Figure 1).
NOTE: The flowmeter and status lights are mounted to the main circuit board but are
considered part of the flow system.
Interconnect terminal strip
The interconnect terminal strip is the nine-point terminal strip near the bottom edge of the
main circuit board. Use the interconnect terminal strip to connect the sample draw
detector to power and external devices.
Transmitter terminal strip
The transmitter terminal strip is the nine-point terminal strip near the right edge of the
circuit board. Use the transmitter terminal strip to connect the transmitter to the main
circuit board.
NOTE: The transmitter is factory-wired to the circuit board. See the “Installation” section
on page 7 for all wiring procedures related to the sample draw detector.