RKI Instruments Inert Gas Testing Eagle with Two Pumps - Manual (Page 15)

Eagle Instruction Manual Description • 9
ZERO and SPAN controls. A bracket secures the sensor/amplifier
assembly to the instrument case. A flow adapter connected to the
sensor allows the sample to flow through the H
2
compensated CO
sensor. A seven-position connector plugs into the EC4 (channel 4)
socket on the analog PCB. The sensor uses a fourth electrode to “null”
(compensate) for hydrogen interference. Hydrogen concentrations
less than 5000 ppm (approximately 12 %LEL) will not produce a
response on this CO sensor.
Circuit Boards
The Eagle circuit boards analyze, record, control, store, and display
the information collected.
The analog PCB is mounted perpendicular to the base of the
instrument case. It is located in the same half of the case as the sensors
and sample-drawing system. The sensor leads connect to the analog
PCB.
The main PCB is mounted in the top half of the case. It includes the
methane elimination and CAL/SETUP switches.
CAUTION: The circuit boards should be serviced only by authorized repair
personnel.
Methane Elimination Switch
The methane elimination switch (SW1) is mounted near the top right
corner of the main PCB.
For applications where methane is an interfering gas, you can set the
methane elimination switch to eliminate most response to methane
(see “Appendix B: Methane Elimination” on page 57). An external
methane elimination switch is available as an option.
CAL/SETUP Switch
The CAL/SETUP switch (SW2) is mounted near the middle left edge
of the main PCB.
This switch controls the Eagle functions available to the user by
disabling the SHIFT/▼ button. Without the use of this button, the
user is unable to enter Calibration or Setup mode. (Display mode is
available with either switch setting.) See “Setting User Access” on
page 14
to change the switch setting.