SO4 Response Check/ Adjustment

 

Purpose:  The SO4 response check/adjustment assures that the SO4 analyzer has the correct gas calibration.  This can be accomplished by introducing a known quantity of gas to the inlet and checking the response on the instrument.  The terminology for this type of check is GRC (Gas Replacement Calibration).  Each GRC has a RF (Response Factor).  This RF value should be 1.000. 

 

Required Equipment:  Precision flat head screwdriver

 

Reference:  SOPMAN Pages XX-XX

 

 

SO4 Analyzer Background Check and Adjustment

 

1.        Open the Gas Calibration worksheet.

2.        On DataView go to the tools tab and select Trigger Cals.

3.        In the trigger cals menu select SO4 GRC Zero and press Start Calibration.

4.        Under the tools tab select Query 1-Minute Data.  In the query data tool menu select SO4.

5.        Enter the Background (BKG) or Zero Potentiometer (Zero Pot) number onto the Gas Calibration worksheet in the Zero Baseline Adjustment section.  The number should be entered in the as found column.

a.        To find the BKG number on a 43CTL analyzer scroll down to Calibration Factors and press enter.  Then scroll to SO2 BKG PPB and press enter.  The top number is the PPB (Parts Per Billion) number for the analyzer and the bottom number is the BKG number.

b.       On a 43S analyzer the Zero Pot is on the front of the instrument.  Read the number in the window then the number on the hash marks and then count the number of hash marks from the main number to the pointer.  (Ex.:  window = 2, main hash mark number = 7, the number of hash marks from the main number to the pointer = 4 – From this information the Zero Pot number is 2.74.)

6.        Wait until the SO4 number is stable.  (In some cases it may take 10-15 minutes for the SO4 analyzer to stabilize.)  Press Get Data on the query data tool.  If the data numbers are approximately equal to the number on DataView then the data is stable and an average can be taken.

7.        Enter the SO4 data in the as found Zero Baseline Adjustment section of the Gas Calibration worksheet.  The PPB number should be approximately 1.00.  If it isn’t, adjust the BKG or Zero Pot.

a.        If you have a 43CTL analyzer it should already be in the adjustment screen (follow step 6).  Use the up and down arrows to adjust the Background number so that the SO2 PPB number is ~1.00.  When this is complete press enter on the analyzer.

b.       On a 43 S analyzer adjust the Zero Pot until the SO2 PPB reading is approximately 1.00.

8.        Record the final BKG and/or Zero Pot number in the as left cell of the Gas Calibration worksheet.

9.        On the query data tool press Get Data and enter the SO4 number in the as left cell of the Gas Calibration worksheet.

10.     Press Run or Auto on the analyzer and close the Trigger Cals Menu.

 

SO4 Analyzer Response Check

 

1.        This procedure will obtain the initial or current RF value for the SO4 analyzer.

2.        Open the Gas Calibration Worksheet and enter the correct SO2 concentration (found on the gas cylinder) in the blank provided.

3.        Enter the final SO4 PPB number from the Zero Baseline adjustment into the as found zero of the SO4 Analyzer Response.

4.        On DataView go to the tools tab and select Trigger Cals.

5.        In the Trigger Cals menu, select SO4 GRC Point 1 and press Start Calibration.

6.        Under the tools tab select Query 1-Minute Data.  In the query data tool menu select Air MFC, Gas MFC and SO4.

7.        Wait 20 minutes or until the data for the SO4 isn’t changing by more than 0.05 PPB per minute.  This is so that the instruments can equalize before going on to the next step.

8.        Press Get Data on the query data tool.  If the query data numbers are approximately equal to the number on DataView then the data is stable and an average can be taken.

9.        Enter the Air MFC, Gas MFC and SO4 data in the as found section of the Gas Calibration worksheet.  Also enter the COEF or Span Pot number.

a.        To find the COEF (Coefficient) number on a 43CTL analyzer scroll down to Calibration Factors and press enter.  Then scroll to SO2 COEF and press enter.  The top number is the PPB (Parts Per Billion) number for the analyzer and the bottom number is the COEF number.

b.       On a 43S analyzer the Span Pot is on the front of the instrument.  Read the number in the window then the number on the hash marks and then count the number of hash marks from the main number to the pointer.  (Ex.:  window = 2, main hash mark number = 7, the number of hash marks from the main number to the pointer = 4 – From this information the Zero Pot number is 2.74.)

10.     Go to Trigger Cals and press Stop Calibration then select SO4 GRC Zero and press Start Calibration.

11.     Wait 7-10 minutes or until the data for SO4 is stable.  (In some cases it may take 10-15 minutes for the SO4 analyzer to stabilize.)  Press Get Data on the query data tool.

12.     Enter the Air MFC and SO4 data in the as found section of the Gas Calibration worksheet.

13.     The Actual Expected value is calculated by adding the final Zero Value and Calculated Expected Value.

14.     The RF is now displayed at the far right of the worksheet.  If the RF is between 0.98 and 1.02, the calibration check is complete. 

15.     Close the trigger cals window and query data window.

16.     Save the Gas calibration worksheet, and then print the SO4 Response information and fax to Plano.  (Note: you can wait until the response checks for all analyzers are complete before faxing to Plano.)

17.     If the RF is not within the specified range continue with the Analyzer Response Adjustment.

 

SO4 Analyzer Response Adjustment

 

1.        This procedure will be used to adjust the analyzer and obtain a corrected RF value for the SO4 analyzer.

2.        Using the as found data for the SO4 Zero, enter the Air MFC and SO4 values in the as left section.

3.        On DataView go to the tools tab and select Trigger Cals.

4.        In the Trigger Cals menu, select SO4 GRC Point 1 and press Start Calibration.

5.        Under the tools tab select Query 1-Minute Data.  In the query data tool menu select Air MFC, Gas MFC and SO4.

6.        Wait 7-10 minutes or until the data for SO4 is stable.   (In some cases it may take longer for the SO4 analyzer to stabilize.)

7.        Adjust the instrument.

a.        On 43CTL analyzers push menu.  Scroll down to CAL FACTORS and push ENTER.  Go to the SO2 COEF and press enter – Set the SO2 COEF to 1.0.  The PMT can be adjusted by taking the top off of the analyzer.   With the top of the analyzer off, look on the left side of the bulkhead at the front.  There is a blue box with an orange grommet on the top.  Inside the grommet is the PMT adjustment screw.  Slowly adjust the analyzer until the SO2 ppb on the analyzer, or SO4 on DataView, is approximately equal to the Actual Expected value from the as found section.  The PMT adjustment screw on the inside of the analyzer is a coarse adjustment and the SO2 COEF is a fine adjustment.  The SO2 COEF should always be close to a standard of 1.00 but it can be used to adjust the instrument to a tighter tolerance.  The SO2 COEF will adjust the instrument in smaller increments than the PMT adjustment.  Replace the top of the analyzer.

b.       On 43S analyzers set the Span Pot to 5.00.  Open the front door on the analyzer and slowly adjust the PHOTOMULTIPLIER GAIN screw until the SO2 reading on the analyzer, or SO4 on DataView, is approximately equal to the Actual Expected value from the as found section.  The PMT adjustment screw on the inside of the analyzer is a coarse adjustment and the Span Pot is a fine adjustment.  The Span Pot should always be close to a standard of 5.00 but it can be used to adjust the instrument to a tighter tolerance.  The Span Pot will adjust the instrument in smaller increments than the PMT adjustment.

8.        When the analyzer adjustments are complete, let the analyzer stabilize for 7-10 minutes.  Press Get Data on the query data tool.

9.        Enter the Air MFC, Gas MFC and SO4 data in the as found section of the Gas Calibration worksheet.  Also enter the COEF or Span Pot number.

10.     The RF is now displayed at the far right of the worksheet.  If the RF should now be between 0.98 and 1.02, the calibration adjustment is complete.  If the RF is not within spec, repeat the adjustment part of the procedure again.

18.     Go to Trigger Cals and press Stop Calibration then select SO4 GRC Zero and press Start Calibration.

19.     Wait 7-10 minutes or until the data for SO4 is stable.  (In some cases it may take longer for the SO4 analyzer to stabilize.)  Press Get Data on the query data tool.

20.     Enter the Air MFC and SO4 data in the as left section of the Gas Calibration worksheet.

21.     The RF is now displayed at the far right of the worksheet.  If the RF is between 0.98 and 1.02, the calibration adjustment is complete.  If the RF is not within spec, repeat the adjustment part of the procedure again. 

22.     Close the trigger cals window and query data window.

23.     Save the Gas calibration worksheet, and then print the SO4 Response information and fax to Plano.  (Note: you can wait until the response checks for all analyzers are complete before faxing to Plano.)