RKI Instruments Eagle Series - Manual (Page 63)

Diffusion Eagle Instruction Manual Appendix B: Methane Elimination • 58
Appendix B: Methane Elimination
For applications where methane is an interfering gas, you can set the Eagle to
eliminate most response to methane. The methane elimination switch is a
standard feature on the circuit board inside the top of the Eagle’s case. An
external switch is available as an option. For this type of detection, the
combustible gas channel must be programmed to display HEX or *** (see
“Updating Channel Settings” on page 29.) Eagles with the external methane
elimination switch are factory-set with the correct display.
Setting up for methane elimination mode
1. Take the Eagle to a fresh-air environment. Set the internal methane
elimination switch to the HEX ON position or the external switch to
Methane Response Off.
CAUTION: If the Eagle is equipped with an external methane
elimination switch, do not adjust the internal switch. The
internal switch should always be in the CH4 position.
2. Allow 2 minutes for the combustibles sensor to stabilize.
3. Perform the demand zero procedure as described in “Preparing for
Calibration” on page 46.
WARNING: DO NOT adjust the switch after re-zeroing the Eagle.
Response to CH
4
is greatly reduced when the internal switch is
set to “HEX ON” or the external switch is set to “Methane
Response Off”. If used for methane detection, the internal
switch must be set to “CH4” or the external switch set to
“Methane Response On”.
Operating with methane response off
Monitor for combustible gas as you normally would. When the Eagle is
operating in Methane Elimination mode, response to methane is reduced by
90% or more. Response to hexane is reduced slightly (approximately 15%).
To convert readings for most common combustible gases, see Table 7 on
page 59.
Returning to methane response mode
1. Take the Eagle to a fresh-air environment. Set the internal methane
elimination switch to the CH4 position or the external switch to Methane
Response On.
2. Allow 2 minutes for the combustibles sensor to stabilize.