Siemens SITRANS SL Operating Instructions Manual page 10

Step 5: Verification
1. Watch or record the measured value for at least 20 seconds to ensure that it is stable (i. e. concentration varies not
more than ±0.2 vol %/minute).
2. Take 5 successive concentration values and write them into the verification sheet.
3. If the difference between the highest and the lowest concentration value is more than the maximum repeatability value
of 2 %, the measurements must be repeated.
4. Calculate the average of the 5 verification measurement values.
5. Multiply the averaged verification measured values with the temperature compensation and pressure compensation
factors given in the verification kit certificate of the instrument.
The following formula applies: Verification value = measured value x temperature compensation factor x pressure
compensation factor.
6. Compare the verification value with the reference measured value given in the verification kit certificate. If the
verification value exceeds the range of the reference measured value by more than ±1 % vol please contact the
Siemens support.
Step 6: Purging with nitrogen
To make sure that the instrument was purged well all the time during the verification procedure another purging
procedure with nitrogen is necessary. To do so:
1. R03 option: Attach your nitrogen source to the remaining needle valve once more.
R02 option: Attach your nitrogen source directly to the transmitter.
2. Purge the verification tube for about 5 minutes until the concentration value falls well below 0.3 vol % O
should be approx. 4 l/min.
If the O concentration value does not fall below 0.3 vol % O
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volume behind the lenses during verification. The verification procedure should be repeated from the start.
3. Close the needle valve. Wait for 10 minutes. After this time the O
more than 0.15 vol % O
4. Note this value in the verification sheet.
Step 7: Restore
1. Restore path length, pressure correction and temperature correction to original settings according to the notes taken.
2. After restoring correction settings, press
3. Reinstall the receiver and transmitter at the industrial interfaces.
Troubleshooting: Insufficient purging
If the oxygen concentration in the verification tube moves above 0.15 vol % after having been purged with nitrogen, this
may be due to an elevated oxygen content inside the housing units. To remove that oxygen you can follow one of the
two procedures below depending on your permission to open the lids of the housing. If you are not permitted to open
the lids, you shall just keep on purging the verification tube with nitrogen until all oxygen in the housing is gone. This
may take several hours or even a whole day. Thus the purging should be interrupted from time to time to test if the
oxygen content has fallen below 0.15 vol %. If the test result is above 0.15 vol % within a 10 minutes time you must
continue purging with nitrogen.
If you are permitted to open the lids, you should first turn on the nitrogen flow. Then open the lids such that the gas
can easily enter the gap between lid and housing, but without risk of the lids falling off. After 15 minutes of nitrogen
purging the housing should be free of oxygen. After purging first close the lids. Then turn off the nitrogen and wait for
10 minutes. If the oxygen value remains below 0.15 vol %, the problem is solved. If not, repeat the procedure.
Siemens AG
Digital Industries
Postfach 48 48
90026 NÜRNBERG
GERMANY
Amendment 3 to Operating Instructions SITRANS SL Version 04
A5E50017120A, 01/2021
10
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button repeatedly to exit the menu. Select OK when you are asked to save.
it is obvious that too much oxygen has entered the
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concentration value should not have increased to
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Amendment 3 to Operating Instructions SITRANS SL Version 04
. The gas flow
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A5E50017120A-02, 01/2021