Fixed and Variable Set Point MFC Audit Procedure

 

Purpose:  This procedure is to show the steps for Auditing a Fixed or a Variable Mass Flow Controller (MFC).  If the Fixed MFC audit error is greater than +/- 2% it will need to be calibrated.   If the Variable Set Point audit error is greater than +/- 1% it will need to be calibrated.  The error is based on the DAS read out for the MFC and the S avg on the BIOS.

 

Required Equipment:  BIOS

                                            BIOS flow cells (Low, Standard or High)

                                            Flow tubing for BIOS

                                            Wrenches (7/16, 9/16 or 11/16)

                                            DAS (DataView, Query Results, Cal Channel and/or Trigger Cals)

 

Reference:  SOPMAN Pages XX-XX

                               

MFC Flow Rates

The following table shows the correct set points for each MFC.

MFC Setup Table

 

MFC                                   Flow Rate                            BIOS Cell Used                       Process Control

PCM1 – 4 MFC                 16.7 slpm                              High Flow Cell                        PCM DAY1

NO RXN MFC                  1.00 slpm                              STND Flow Cell                      NO RXN FLOW

NO BYP MFC                   1.00 slpm                              STND Flow Cell                      NO BYP FLOW

NOy RXN MFC                1.25 slpm                              STND Flow Cell                      NOy RXN FLOW

NOy BYP MFC                 1.25 slpm                              STND Flow Cell                      NOy BYP FLOW

NO3CH1MFC                   1.25 slpm                              STND Flow Cell                      NO3 CH1 FLOW

NO3CH2MFC                   1.25 slpm                              STND Flow Cell                      NO3 CH2 FLOW

NO3CH3MFC                   1.25 slpm                              STND Flow Cell                      NO3 CH3 FLOW

SO4 MFC                           1.25 slpm                              STND Flow Cell                      SO4 FLOW

CO MFC                            1.00 and 1.25 slpm              STND Flow Cell                      CO FLOW

SO2 MFC                           1.00 and 1.25 slpm              STND Flow Cell                      SO2 FLOW

NH3 MFC                          16.7 slpm                              High Flow Cell                        DICHOT/NH3 ON

Dichot Coarse MFC         1.67 slpm                              STND Flow Cell                      DICHOT/NH3 ON

Dichot Fine MFC             15.0 slpm                              High Flow Cell                        DICHOT/NH3 ON

Air MFC                            Variable                                High Flow Cell                        Air MFC Cal

Gas MFC                           Variable                                Low Flow Cell                         Gas MFC Cal

NO3 Gas MFC                  Variable                                Low Flow Cell                         NO3 Gas MFC Cal

SO4 ADD MFC                Approx. 5 SCCM                Low Flow Cell                         SO4 ADD             

 

 

Using the DC-2 BIOS

 

  1. Turn on the BIOS.  It will go through an initial start up and come to a screen with options RUN, SETUP and LEAK CHECK.
  2. At this point the cursor will be blinking on the RUN option.  Press enter to continue to the next screen.  DO NOT go into the setup mode.
  3. To obtain the temperature and pressure from this screen hold the Select button down for 3 seconds.  The display will now show the date, time, temperature, pressure and volume.
  4. To go back to the flow screen push the reset button.
  5. The BIOS can now be used to obtain flow rates by pressing the Select and Enter button simultaneously.
  6. When changing BIOS cells it is not necessary to turn the unit off.  Simply press the reset button and the Base unit will detect a different cell.  It is now ready to make flow readings.

 

 

Auditing a Fixed Setpoint MFC

 

  1. Start the process by opening the Flow Audit menu on DataView.  It is located on DataView under the Flow Checks tab.
  2. With the Flow Audit menu open select the MFC that is being audited (Be sure to select the MFC and not the inlet).  Now push the button labeled:  “Enter  Flow Check Data”.
  3. Select the appropriate BIOS Cell, according to the MFC Setup Table from above, and connect it to the MFC.  If the MFC has vacuum as the supply then connect it to the right side of the BIOS flow cell and if the supply is pressure connect it to the left side of the BIOS.
  4. If the MFC audited is PCM 1-4 open the Trigger Cals menu and select PCM DAY 1 then push the start calibration button.  The MFC will now start flowing.
  5. If the MFC audited is NH3 or a Dichot MFC open the Trigger Cals menu and select Dichot/NH3 ON then push the start calibration button.  The MFC will now start flowing.
  6. For Fixed Set Point MFCs turn on the BIOS and collect 3 10 - point BIOS V averages and S averages at the MFC.  Average each of those and enter them into the MFC Flow Audit Entry Form.
  7. Collect a minimum of 2-1 minute averages of DAS flow data using the Query Results tool to get the average.  Enter this information into the MFC Flow Audit Entry Form in the blank labeled ‘SiteManager Flow Rate’.
  8. With the MFC Flow Audit Entry Form complete push the ‘Calculate’ button.  If all of the data is correct push the ‘Yes’ button under Save Data.  If not push the ‘No’ button and correct the data.  
  9. If the MFC Flow Error is more than +/- 2% then calibrate the MFC.  To change to another MFC after an audit has been saved push the ‘Yes’ button under Change Device.

 

Auditing a Variable Set Point MFC

  1. Start the process by opening the Flow Audit menu on Dataview.  It is located on DataView under the Flow Checks tab.
  2. With the Flow Audit menu open select the MFC that is being audited (Be sure to select the MFC and not the inlet).  Now push the button labeled:  “Enter Flow Check Data”.
  3. Select the appropriate BIOS Cell, according to the MFC Setup Table from above, and connect it to the MFC.  If the MFC has vacuum as the supply then connect it to the right side of the BIOS flow cell and if the supply is pressure connect it to the left side of the BIOS.
  4. For a Variable Set Point MFC open the Cal Channel window by selecting “Calibrate DAS Channel” under the Dataview Setup tab.  With Cal Channel open select the correct channel name of the MFC being calibrated.  The DAS value and instantaneous DAP Integer will appear under the channel name.
  5. The cal channel window should now have the correct MFC selected under channel name.   Each MFC has a process control associated with it.  Using the MFC Setup Table from above select the appropriate process control in the “Process Control List” at the bottom of the Cal Channel window.  Then press the Run Selected Process Control button.
  6. Now that the MFC is selected, input 5000 into the “New DAP Value” window and push the “Update DAP Value” button. 
  7. Collect 3 10 - point BIOS V averages and S averages at the MFC.  Average each of those and enter them into the MFC Flow Audit Entry Form.
  8. Collect a minimum of 2-1 minute averages of DAS flow data using the Query Results tool to get the average.  Enter this information into the MFC Flow Audit Entry Form in the blank labeled ‘SiteManager Flow Rate’.
  9. With the MFC Flow Audit Entry Form complete push the “Calculate” button.  If all of the data is correct push the “Yes” button under Save Data.  If not push the “No” button and correct the data.  For each setpoint note the MFC Flow Error percentage.  
  10. Repeat steps 7-9 for a DAP value of 10000, 15000, 20000 and 30000.  
  11. If the MFC Flow Error on any of the setpoints is more than +/- 1% then calibrate the MFC.  To change to another MFC after an audit has been saved push the “Yes” button under Change Device.