Claims
- 1. A method for obtaining H.sub.2 S concentration readings using an H.sub.2 S sensor which provides a voltage output based on H.sub.2 S concentration, the method comprising the steps of:
- providing a zero H.sub.2 S concentration gas to the sensor for a period of time to ensure a zero level environment and obtaining a zero voltage reading;
- providing a set maximal H.sub.2 S concentration gas to the sensor for a period to ensure a maximal level environment and obtaining a full scale voltage reading;
- purging the sensor for a period to provide a substantially zero level environment;
- providing a set concentration of H.sub.2 S bearing gas to the sensor for a period of time to provide a set voltage change;
- determining the slope of the concentration to voltage curve of the sensor for the set voltage change;
- adjusting a stored concentration to voltage curve to conform with the zero and full scale voltage readings and the slope determination;
- again purging the sensor to provide a substantially zero level environment;
- monitoring the voltage change as said again purging step is occurring to provide a first clearing rate;
- adjusting the stored concentration to voltage curve to conform with the first clearing rate;
- providing the set concentration of H.sub.2 S bearing gas to the sensor for the same period as required to provide said set voltage change;
- determining the slope of concentration to voltage curve resulting from said providing for said same period step;
- adjusting the stored concentration to voltage curve to conform with the slope determination determined based on the same period step;
- yet again purging the sensor to provide a substantially zero level environment after the providing for the same period step;
- monitoring the voltage change as the yet again purging is occurring to provide a second clearing rate;
- adjusting the stored concentration to voltage curve to conform with the second clearing rate;
- providing a sample gas to be measured to the sensor after adjusting the stored concentration to voltage curve to conform with the second clearing rate;
- measuring the voltage of the sensor in the presence of the sample gas; and
- linearizing the measured sample gas sensor voltage using the stored concentration to voltage curve and providing an H.sub.2 S concentration reading.
- 2. The method of claim 1, further comprising the step of:
- returning to the again purging step after providing said H.sub.2 S concentration reading to obtain a next concentration reading.
- 3. The method of claim 2, wherein the loop from said again purging step to said linearizing step is performed every 2 to 3 minutes.
- 4. The method of claim 1, further comprising the steps of:
- adjusting the gain of the sensor to increase output voltage after each step of adjusting the stored concentration to voltage curve to conform with the slope determination.
SPECIFICATION
This is a division of application Ser. No. 08/074,271 filed Jun. 8, 1993, now U.S. Pat. No. 5,356,458 which is a continuation of 07/743,815 filed Aug. 12, 1991 now abandoned.
US Referenced Citations (6)
Divisions (1)
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74271 |
Jun 1993 |
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Continuations (1)
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743815 |
Aug 1991 |
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