Campbell Scientific IRGASON Integrated CO2/H2O Open-Path Gas Analyzer and 3D Sonic Anemometer User Manual

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IRGASON

Integrated CO

O Open-Path Gas Analyzer and 3D Sonic Anemometer

The first part of the following procedure simply measures the CO

and H

zero and span, without making adjustments. This allows the CO

and H

O gain

factors to be calculated. These gain factors quantify the state of the analyzer

before the zero-and-span procedure, and in theory could be used to correct

recent measurements for drift. The last part of the zero-and-span procedure

adjusts internal processing parameters to correct subsequent measurements.

If the zero-and-span procedure is being performed off-site (e.g., in a lab), be

sure to mount the IRGASON on the lab stand (pn 27278). This will ensure the

analyzer is in the correct upright orientation and has the correct optical

alignment.

It is imperative that the zero-and-span procedure be done correctly and not

rushed; allocate plenty of time for the procedure (at least an hour).

Resting the analyzer on its side during the zero-and-span

procedure may result in measurement inaccuracy.

To check and then set the IRGASON zero and span, follow the steps below:

1. Remove power from the EC100.

2. If not already done, clean the windows and snouts with alcohol and a non-

scratching tissue or cloth.

Make sure the alcohol and any residual water completely

evaporate from the analyzer before proceeding with the

zero-and-span procedure.

3. As shown in FIGURE 9-4, position the IRGASON zero-and-span shroud

(pn 26390) over the upper and lower snouts. To do this, twist the two ends

of the shroud together to minimize the length of the shroud. Make sure the

rubber seals on the ends of the shroud are clean and in good condition.

Position one end of the shroud over the lower snout and twist the top part

of the shroud, allowing it to extend and cover the upper snout; while doing

so, avoid making contact with the sonic transducers. Continue twisting the

shroud until it is fully extended and covering both snouts. Twist the

shroud so that the gas tubes and temperature thermistor cable are directed

towards the back of the sensor. Hang the tubes and cable over the trunk of

the sensor to alleviate any strain on the optical arms. See FIGURE 9-4,

The zero-and-span shroud mounted on the zero-and-span stand.

CAUTION