35-3010RK-04 Sample-Draw Detector • 7
Amp 1 and Amp 2 Circuits
These circuits are located to the left of the sensor/transmitter terminal strip. They each
include test points, a zero pot, and a span pot. Amp 1 is on the left and is for the CO
channel. Amp 2 is on the right and is for the H
2
S channel.
The zero and span pots are used during calibration. Use the span pot to make adjustments
to gas response readings and the zero pot to make adjustments to the zero reading.
The test points are labeled CAL-1 and CAL+1 for the CO channel and CAL-2 and CAL+2
for the H
2
S channel. A 100 mV - 500 mV output is available at the CO test points for use
during calibration. No output is available at the H
2
S test points since no H
2
S sensor is
installed in the 35-3010RK-04.
Pump Terminal Strip
The pump terminal strip is the four-point terminal in the top left corner of the circuit
board. Use the pump terminal strip to connect the pump and pressure switch to the main
circuit board.
NOTE:
The pump and pressure switch are factory-wired to the circuit board. See
“Wiring the Sample Draw Detector” on page 9 for all wiring procedures related
to the sample draw detector.
Relay
The relay is approximately in the middle of the circuit board. The relay is a four pole,
double-throw (4PDT) relay and is rated for 2 amps at 25 VDC (resistive). If the pressure
switch senses a low flow condition, the relay interrupts the 4-20 mA signal from the CO
channel and opens one of the lines from the LEL sensor which will cause a downscale
reading at the controller resulting in a fail alarm on these channels.
Reset Switch
A small reset button is located in the upper left corner of the main PCB. When a low flow
condition occurs, the pump will be shut off. To reset the low flow condition and start the
pump again, press and hold the reset switch for about 2 seconds, then release.
