Maxtec MaxO2+ Bedienungsanleitung Seite 6

For hospital and home care a new calibration is
required when:
The measured O2 percentage in 100% O2 is below 97.0% O2.
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The measured O2 percentage in 100% O2 is above 103.0% O2.
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The CAL reminder Icon is blinking at the bottom of the LCD.
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If you are unsure about the displayed O2 percentage. (see Factors influencing accurate
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readings.)
For ID testing, (or optimum accuracy) a new calibra-
tion is required when:
The measured O2 percentage in 100% O2 is below 99.0% O2.
•
The measured O2 percentage in 100% O2 is above 101.0% O2.
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The CAL reminder Icon is blinking at the bottom of the LCD.
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If you are unsure about the displayed O2 percentage (see Factors influencing accurate
•
readings).
A simple calibration may be made with the sensor open to static ambient air. For optimum
accuracy Maxtec recommends that the Sensor be placed in a closed loop circuit where gas flow
is moving across the sensor in a controlled manner. Calibrate with the same type of circuit and
flow that you will use in taking your readings.
2.2.1 In Line Calibration
(Flow Diverter – Tee Adapter)
1. Attach the diverter to the MaxO2+ by threading it on to the bottom of the sensor.
2. Insert the MaxO2+ in the center position of the tee adapter. (FIGURE 1, A)
3. Attach an open-ended reservoir to the end of the tee adapter. Then start the
calibration flow of oxygen at two liters per minute.
4. Six to 10 inches of corrugated tubing works well as a reservoir. A calibration oxygen
flow to the MaxO2+ of two liters per minute is recommended to minimize the
possibility of obtaining a "false" calibration value.
5. Allow the oxygen to saturate the sensor. Although a stable value is usually observed
within 30 seconds, allow at least two minutes to ensure that the sensor is completely
saturated with the calibration gas.
6. If the MaxO2+ is not already turned on, do so now by pressing the analyzer "ON"
button.
7. Press the Cal button on the MaxO2+ until you read the word CAL on the analyzer
display. This can take approximately 3 seconds. The analyzer will now look for a
stable sensor signal and a good reading. When obtained, the analyzer will display the
calibration gas on the LCD.
NOTE: Analyzer will read "Cal Err St" if the sample gas has not stabilized.
2.2.2 Direct Flow Calibration (Barb)
1. Attach the Barbed Adapter to the MaxO2+ by threading it on to the bottom of the
sensor.
2. Connect the Tygon tube to the barbed adapter. (FIGURE 1, B)
3. Attach the other end of the clear sampling tube to a source of oxygen with a known
oxygen concentration value. Initiate flow of the calibration gas to the unit. Two liters
per minute is recommended.
4. Allow the oxygen to saturate the sensor. Although a stable value is usually observed
within 30 seconds, allow at least two minutes to ensure that the sensor is completely
saturated with the calibration gas.
5. If the MaxO2+ is not already turned on, do so now by pressing the analyzer "ON"
button.
6. Press the Cal button on the MaxO2+ until you read the word CAL on the analyzer
display. This can take approximately 3 seconds. The analyzer will now look for a
stable sensor signal and a good reading. When obtained, the analyzer will display the
calibration gas on the LCD.
ENGLISH
3 FACTORS INFLUENCING
ACCURATE READINGS
3.1 Elevation/Pressure Changes
Changes in elevation result in a reading error of approximately 1% of reading per 250 feet.
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In general, calibration of the instrument should be performed when elevation at which the
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product is being used changes by more than 500 feet.
This device does not automatically compensate for changes in barometric pressure or
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altitude. If the device is moved to a location of a different altitude, it must be recalibrated
before use.
3.2 Temperature Effects
The MaxO2+ will hold calibration and read correctly within ±3% when at thermal equilibrium
within the operating temperature range. The device must be thermally stable when calibrated
and allowed to thermally stabilize after experiencing temperature changes before readings are
accurate.
For these reasons, the following is recommended:
For best results, perform the calibration procedure at a temperature close to the
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temperature where analysis will occur.
Allow adequate time for the sensor to equilibrate to a new ambient temperature.
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CAUTION: "CAL Err St" may result from a sensor that has not reached thermal equilibrium
When used in a breathing circuit, place the sensor upstream of the heater.
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3.3 Pressure Effects
Readings from the MaxO2+ are proportional to the partial pressure of oxygen. The partial
pressure is equal to the concentration times the absolute pressure.
Thus, the readings are proportional to the concentration if the pressure is held constant.
Therefore, the following are recommended:
Calibrate the MaxO2+ at the same pressure as the sample gas.
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If sample gases flow through tubing, use the same apparatus and flow rates when
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calibrating as when measuring.
3.4 Humidity Effects
Humidity (non-condensing) has no effect on the performance of the MaxO2+ other than diluting
the gas, as long as there is no condensation. Depending on the humidity, the gas may be diluted
by as much as 4%, which proportionally reduces the oxygen concentration. The device responds
to the actual oxygen concentration rather than the dry concentration. Environments where
condensation may occur are to be avoided since moisture may obstruct passage of gas to the
sensing surface, resulting in erroneous readings and slower response time.
For this reason, the following is recommended:
Avoid usage in environments greater than 95% relative humidity.
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When used in a breathing circuit, place the sensor upstream of the humidifier.
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HELPFUL HINT: Dry sensor by lightly shaking moisture out or flow a dry gas at two liters per
minute across the sensor membrane.
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