35-3010A-12 Sample-Draw Detector • 11
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 sixteen-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 an external device.
Sensor/Transmitter Terminal Strip
The sensor/transmitter terminal strip is the sixteen-point terminal strip near the right edge of the
circuit board. Use the transmitter terminal strip to connect sensors or transmitters to the main
circuit board.
NOTE:
The sensors and transmitters are factory wired to the sensor/transmitter terminal strip.
See “Wiring the Sample-Draw Detector” on page 13 for all wiring procedures related to
the sample-draw detector.
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 each set of test points for use during cali-
bration.
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 13 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 H
2
S and CO channels which
will cause a downscale reading at the controller or recording device.
NOTE:
There is no flow fail indication for the oxygen channel on the 35-3010A-12.
Reset Switch
A small reset button is located in approximately 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.