Document Number: 004-0043 Window Reference Procedure - M500/600 P Probes, version 6.0 and higher FBRM CI Software The Window Reference Procedure is the standard calibration procedure used to reference the Lasentec FBRM instrument focal point to the window surface. This procedure is for an M-series process P probe that is being used with version 6.0 and higher of the Lasentec Control Interface (CI) software. See the table below for the appropriate window reference procedure to use with each probe and software type: Probe Type Software Window Reference Procedure M-series lab L probe Version 6.0 and higher M-series process P probe Version 6.0 and higher Instruction Sheet 004-0042 Instruction Sheet 004-0043 (this document) M-series process P probe Version 5.4 Instruction Sheet 004-0010a M-series lab L probe Version 5.4 Instruction Sheet 004-0010b This procedure is required to calculate the Lasentec FBRM focal point position, which is necessary to ensure measurement-to-measurement repeatability. The measured statistic #/Sec, No Wt 0-5 (Statistic #5) will reach a maximum value (also called the peak value) when the focal point is located at the window reference position. The Window Reference Procedure should be performed: If the PVC Reference Procedure indicates the Lasentec FBRM instrument is out of calibration For non-standard probe orientations (see Orienting the Probe below) Orienting the Probe At the factory, the probe is calibrated in a vertical position with the window pointing down, as it is in the fixed beaker stand. The vertical (window down) window reference position must be known before the Window Reference Procedure can be run. Important! If the orientation of the process installation is greater than ±30 from a vertical (window down) position, this Window Reference Procedure should be performed with the Lasentec FBRM probe in the same orientation as in the process installation (i.e., horizontal, vertical, or at a given angle). 004-0043 Rev F Page 1 of 11
Reading the Micrometer The micrometer, located towards the back of the Lasentec probe body on an M-series process probe, is used to adjust the focal point position. As shown in Figure 1, the scale on the micrometer spindle provides the relative position of the focal point in millimeters to the nearest 0.5 mm. The scale on the rotating dial provides the relative position of the focal point in millimeters to the nearest 0.01 mm (10 µm). The combination of the micrometer spindle and rotating dial readings indicate the focal point position. MICROMETER SPINDLE ROTATING DIAL EACH HASH MARK REPRESENTS 0.01mm (10µm) LINEAR SCALE EACH HASH MARK REPRESENTS 0.5mm MICROMETER POSITION = 5.710 mm ( 5.500 mm + 0.210 mm ) CLOCKWISE = LOWER NUMBER Figure 1 Reading the Micrometer Turning the rotating dial clockwise causes the micrometer reading to decrease. As the rotating dial is turned clockwise, it moves to the left (or down if the probe is in a vertical position), hiding more and more of the incremental hash marks on the micrometer spindle until a 0.00 micrometer position (all hash marks covered) is achieved. Establish the correct perspective of the micrometer before making adjustments. All directions (clockwise or counterclockwise) are written as if the Lasentec probe were in a vertical position (e.g., in a fixed beaker stand), with the user looking down at the micrometer in the direction of the probe tip. The table below shows the distance moved in both millimeters (mm) and microns (µm) as related to the hash marks on the rotating dial and its number of rotations. This information will be important as you make the coarse, mid-range, and fine adjustments in the Locating the Window Reference Position step below. 004-0043 Rev F Page 2 of 11
Distance (mm) Distance (µm) Increments (hash marks on the Rotating Dial) Movement of the Rotating Dial 1 1000 100 2 full turns 0.5 500 50 1 full turn 0.1 100 10 1/5 of a turn 0.01 10 1 1/50 of a turn 0.005 5 ½ 1/100 of a turn Coating the Window Surface Using the Lasentec Marker Before locating the window reference position, coat the Lasentec FBRM probe window with erasable ink. To coat the window surface: 1. Using the Lasentec Dry Erase Marker provided with the Lasentec hardware, coat the surface of the clean, dry Lasentec FBRM probe window with a uniform, thick layer of ink. While most black, dry-erasable markers will do, it is best to use the marker provided by Mettler-Toledo AutoChem to ensure measurement-to-measurement conformity. 2. Allow two minutes for the ink to dry. Configuring version 6.0 and higher of the FBRM CI Software to Locate the Window Reference Position Before locating the window reference position, verify that the Acquisition Module of version 6.0 and higher of the FBRM CI software is running and configured per the directions below. With the CI software, the micrometer position can be adjusted while the Lasentec instrument output is monitored. To configure the software to locate the window reference position: 1. From the Setup Menu, select Meas. Config. 2. For Measurement Duration, select 5 sec (or 10 sec if using a low-speed optical line driver). 3. For Time Averaging, select No Time Averaging. 4. For Channel Grouping, select 0-100 µm 200 Linear Ch. 5. Click the Open File for Save button. 6. Open file C:\Fbrm6?\Backup\SN-X-mmddyy-WRP 1 and click Save. 1 SN = the instrument s serial number X = electronics type (F or C) mmddyy = current date 004-0043 Rev F Page 3 of 11
7. For When Saving to File, save every v Measurements, set it to save every 1 measurement. 8. Press the NOT Measuring: Press to Start button. 9. From the Setup Menu, select Stat. Config. 10. Press the Load Stats. Config button. 11. From the C:\Fbrm6?\Statistics Setup Files folder, select the default0-100-lin.sta statistics setup (the measured statistic #/sec, No Wt 0-5 will reach a maximum value when the focal point is located at the window reference position) and click Open. 12. From the Display Menu, select Stats. 13. In the Show column, make sure there is an X next to the #/sec, No Wt 0-5 statistic (Statistic #5). This will create a trend plot in the trend display once you begin measuring data. 14. Deselect all other statistics by clicking on any existing Xs in the Show column. Deselecting a statistic will remove the trend from the trend display. 15. Under X-axis Scale (located below the trend display), select Record. 16. Under Buffer Length, type in 450. 17. To autoscale the X- and Y-axes, push both toggle switches (under the Trend Display graph) to the right. 18. From the Setup Menu, select Annotation. 19. Make sure the box next to Save with All Records contains an X. 20. Click the Y-axis applies to: box (located below the trend display) and select the #5 statistic. 21. Press the Measuring: Press to Stop button. WRP = window reference procedure (A file name of 550-F-010101-WRP means the file is the calibration procedure for the unit with serial number 550, using F electronics, taken on January 1, 2001.) 004-0043 Rev F Page 4 of 11
Locating the Window Reference Position Locating the window reference position takes less than 25 minutes. It is important that this entire process be carried out continuously without interruption. If interrupted, begin again from step 1 of the coarse adjustment below. Important! Establish the correct perspective of the micrometer before making adjustments. All directions (clockwise or counterclockwise) are written as if the Lasentec FBRM probe were in a vertical position (e.g., in a fixed beaker stand), with the user looking down at the micrometer in the direction of the probe tip. To eliminate the effects of hysteresis, you must always reach the micrometer position on an M-series process probe turning counterclockwise. If you pass the desired micrometer position, move the rotating dial at least 500 µm (one full turn) clockwise and then find the correct point moving counterclockwise. Coarse Adjustment The micrometer position is moved in 0.5 mm increments (one full turn of the rotating dial) to pass the peak value for Statistic #5. Several coarse adjustments may be required before the peak value is passed. To perform coarse adjustment of the micrometer: 1. Grasp the rotating dial on the micrometer and turn it clockwise until the 0 on the rotating dial is lined up with the vertical line on the micrometer spindle and the left (or bottom) edge of the rotating dial is lined up with the 0 line on the micrometer spindle. This is referred to as zeroing the micrometer. Depending on where the micrometer was set, you may need to make several full turns of the rotating dial before you reach the zero position. 2. In the Acquisition Module of the FBRM CI software, make sure Annotation is selected from the Setup Menu, then enter the current micrometer position in the Annotation field (i.e., micrometer = 0.00). 3. From the Display Menu, make sure Stats is selected and an X is displayed in the Show box next to Statistic #5. (You will need to be able to see the Current Value box for Statistic #5 when you begin adjusting the micrometer.) 4. Press the NOT Saving, Press to AutoSave button to begin saving to the data file. 5. Press the NOT Measuring, Press to Start button to begin measuring. 6. Wait until the # Meas Since Start box displays 5 (i.e., 5 measurements have been taken), then click the Saving Data: Press to Stop button to stop saving and the Measuring: Press to Stop button to terminate the measurement. 7. Look at the Current Value displayed for Statistic #5. If the micrometer position is still at 0.00 (i.e., you have not yet made any coarse adjustments), the value displayed may still be 0.00. After a 004-0043 Rev F Page 5 of 11
few coarse adjustments this value will begin to increase and data will display in the trend display graph. 8. Slowly turn the rotating dial one full turn to the left (50 hash marks). 9. Type this micrometer position (+0.5 mm greater than the last recorded measurement) in the Annotation field (e.g., micrometer = +0.5). 10. Repeat steps 4 through 9 (coarse adjustment) while watching the trend display graph. It may take several coarse adjustments before data will display in this graph and counts will begin to register in the Current Value box. Continue to watch the trend display graph, performing another coarse adjustment after every five measurements. Once counts begin to register you ll notice that they fluctuate up and down by small increments with each measurement and increase dramatically with each adjustment of the micrometer position. If the trend line disappears off the top of the graph at any point, click the Scale All Trends box to reset the Y-axis range. Once the peak value is reached, counts displayed in the Current Value box will begin to decrease and a definite peak will be seen in the trend display graph. Once you see the peak, perform three additional coarse adjustments (1.5 mm) to verify there is no higher peak, then proceed to step 11. 11. To determine the final micrometer position of the coarse adjustment, minimize the Acquisition Module and open the Data Review Module. 12. From the Setup Menu, select Meas Config. 13. Click the Open File button. 14. Select the data file created while the window reference position was being located (C:\Fbrm6?\Backup\SN-X-mmddyy-WRP) and click Open. 15. For Time Averaging, select No Time Averaging. 16. Click the Apply Time Averaging box. 17. For Channel Grouping, select 0-100 µm 200 Linear Ch. 18. From the Setup Menu, select Stat. Config. 19. Press the Load Stats. Config button. 20. From the C:\Fbrm6?\Statistics Setup Files folder, select the default0-100-lin.sta statistics setup (the measured statistic #/sec, No Wt 0-5 will reach a maximum value when the focal point is located at the window reference position) and click Open. 21. From the Display Menu, select Stats/Trend. 22. In the Show column, make sure there is an X next to the #/sec, No Wt statistic (Statistic #5). This will create a trend plot in the trend display. 23. Deselect all other statistics by clicking on any existing Xs in the Show column. Deselecting a statistic will remove the trend from the trend display. 24. From the Y Axis applies to: box, select the #5 statistic. 25. Under X-axis Scale (located below the trend display), select Record. 004-0043 Rev F Page 6 of 11
26. Click the Scale All Trends box to reset the Y-axis. 27. Make sure the Lock Cursor box is not checked (i.e., an X is not displayed), select the + from the trend toolbar (located below the Trend Display), and move the Current Record crosshair on the trend display graph to the peak value measurement of the trended statistic as determined by the fine adjustment (right peak). 28. From the Setup Menu, select Annotation. 29. Look at the Annotation field for the micrometer reading at this maximum value. This is the peak micrometer position of the coarse adjustment (e.g., 2.5 mm). If you still have no counts once the micrometer position has reached 2.0 mm, or if you have not seen a dramatic decrease in value once the micrometer position has reached 5.5 mm, re-coat the probe window with the Lasentec Dry Erase Marker (make certain the window is completely covered with a thick layer of ink) and repeat the coarse adjustment from step 1. Mid-Range Adjustment Adjust or move the micrometer position in 0.02 mm increments (2 hash marks on the rotating dial) in the mid-range adjustment to refine the peak value for Statistic #5. You may make several mid-range adjustments before the peak value is refined. Remember that to eliminate the effects of hysteresis, you must always reach the micrometer position going counterclockwise. If you pass the desired micrometer position, move the micrometer clockwise at least 500 microns (one full turn) and then rotate counterclockwise to find the correct point. To perform mid-range adjustment of the micrometer: 1. With the software set to the Acquisition Module, moving the micrometer clockwise, turn the rotating dial back to the peak micrometer position established in the coarse adjustment (e.g., 2.5 mm), then rotate clockwise 0.5 mm (500 microns or one full turn), and then counterclockwise 0.4 mm (400 microns). 2. Turn the rotating dial two hash marks counterclockwise to increase the micrometer position by 0.02 mm. 3. Type over the previous entry to record this new micrometer position (+0.02 greater than the last recorded measurement) in the Annotation field (e.g., micrometer = 2.52 mm). 4. Press the NOT Saving, Press to AutoSave button to begin saving to the data file. 5. Press the NOT Measuring, Press to Start button to begin measuring. 6. Wait until the # Meas Since Start box displays 5 (i.e., 5 measurements have been taken), then click the Saving Data: Press to Stop button to stop saving and the Measuring: Press to Stop button to terminate the measurement. 004-0043 Rev F Page 7 of 11
7. Repeat steps 2 through 6 at least three times. Look at the trend display graph. The counts should be increasing (i.e., the trend line going up). If they are not, move the rotating dial to the clockwise to a position 0.2 mm less than the micrometer position found in the coarse adjustment (e.g., 2.5 mm) and repeat the mid-range adjustment from step 2. If the trend line has disappeared off the top of the graph, click the Scale All Trends button to reset the Y-axis. Every time the trend display graph shows counts higher than the peak value from the coarse adjustment, this new value should be considered the new peak and steps 2 through 6 should be repeated three additional times. 8. Once the micrometer position has been successfully moved 0.03 mm (30 microns) beyond a distinct maximum value of Statistic #5, record this micrometer position in the Annotation field (e.g., 2.72 mm). This is considered the peak micrometer position of the mid-range adjustment. Fine Adjustment Increase the micrometer position in 0.005mm increments, one-half of a has mark on the rotating dial, to confirm the peak value for Statistic #5. Several fine adjustments may need to be made before confirming the peak value. Remember that to eliminate the effects of hysteresis, you must always reach the micrometer position going counterclockwise. If you pass the desired micrometer position, move the micrometer clockwise at least 500 microns (one full turn) and then find the correct point moving counterclockwise. To perform the fine adjustment of the micrometer: 1. Decrease the micrometer position by 0.5 mm from the peak mid-range adjustment micrometer position by turning the rotating dial one full turn (500 microns) clockwise, then increase the micrometer by 0.45 mm (450 microns) turning counterclockwise. 2. Type over the previous entry to record the new micrometer position (-0.08 less than the midrange peak value) in the Annotation field. 3. Press the NOT Saving, Press to AutoSave button to begin saving to the data file. 4. Press the NOT Measuring, Press to Start button to begin measuring. 5. Wait until the # Meas Since Start box displays 5 (i.e., 5 measurements have been taken), then click the Saving Data: Press to Stop button to stop saving and the Measuring: Press to Stop button to terminate the measurement. 6. Look at the trend display graph. If the trend line has disappeared off the top of the graph, click the Scale All Trends button to reset the Y-axis. 7. Increase the micrometer position by slowly turn the rotating dial counterclockwise one half of one hash mark. 8. Type over the previous entry to record the new micrometer position (+0.005 greater than the last recorded measurement) in the Annotation field (e.g., micrometer = 2.645 mm). 9. Repeat steps 3 through 8 until the peak value established in the mid-range adjustment is passed by 0.025 mm. You will see gradual stair-step increases before the line in the trend display graph gradually decreases. After the peak, the counts will likely fluctuate up and down again, but will not reach as high as they did at the peak. 004-0043 Rev F Page 8 of 11
If counts do fluctuate so multiple peaks are observed, re-coat the window with the Dry Erase Marker and repeat the fine adjustment from step 1. 10. Once the peak value from the mid-range adjustment has been passed by 0.025 mm, open the Data Review Module to determine the exact micrometer position of the maximum peak value using the trend display graph. 11. From the Setup Menu, select Meas Config. 12. Click the Open File button. 13. Select the data file created while the window reference position was being located (C:\Fbrm6?\Backup\ SN-X-mmddyy-WRP) and click Open. 14. For Time Averaging, select No Time Averaging. 15. Click the Apply Time Averaging box. 16. For Channel Grouping, select 0-100 µm 200 Linear Ch. 17. From the Setup Menu, select Stat. Config. 18. Press the Load Stats. Config button. 19. From the C:\Fbrm6?\Statistics Setup Files folder, select the default0-100-lin.sta statistics setup (the measured statistic #/sec, No Wt 0-5 will reach a maximum value when the focal point is located at the window reference position) and click Open. 20. From the Display Menu, select Stats/Trend. 21. In the Show column, make sure there is an X next to the #/sec, No Wt 0-5 statistic (Statistic #5). This will create a trend plot in the trend display. 22. Deselect all other statistics by clicking on any existing Xs in the Show column. Deselecting a statistic will remove the trend from the trend display. 23. From the Y Axis applies to: box, select the #5 statistic. 24. Under X-axis Scale (located below the trend display), select Record. 25. Click the Scale All Trends box to reset the Y-axis. 26. The trend display should look similar to Figure 2 below, with two distinct peaks displayed. The left peak is from the mid-range adjustment and the right peak is from the fine adjustment. 27. Make sure the Lock Cursor box is not checked (i.e., an X is not displayed), select the + from the trend toolbar (located below the Trend Display), and move the Current Record crosshair on the trend display graph to the peak value measurement of the trended statistic as determined by the fine adjustment (right peak). 28. From the Setup Menu, select Annotation. 004-0043 Rev F Page 9 of 11
29. Look at the Annotation field for the micrometer reading at this maximum value. The micrometer position corresponding to this value is the window reference position (e.g., 2.65 mm). In some cases, the maximum value of the trended statistic may be observed at more than one consecutive micrometer position. If a plateau is observed, the last micrometer position encountered at the maximum value of the statistic (i.e., the right-hand side of the plateau in the trend display) should be used as the window reference position (WRP). Figure 2 Example of Trend Display in the Data Review Module Window Reference Procedure Repeatability While all measurements of the window reference position should be within a range of ±5 microns (i.e., ±0.005 mm or one-half of an increment on the rotating dial), due to inconsistencies in ink application, you should not expect actual counts achieved to be the same each time. Contact a Mettler-Toledo Technology and Application Consultant if there is a greater than ±5-micron discrepancy in the measurement of the window reference position. 004-0043 Rev F Page 10 of 11
Setting the Micrometer at the Standard Focal Point Position ( P Probes) The focal point position defines the location of the focal point relative to the external surface of the Lasentec probe window. The standard focal point position for an M-series process probe is 20 microns inside the sapphire window surface. Unless there is a specific, application-based need for an alternate position, use the standard focal point position for all applications. To set the micrometer at the required focal point position for an M-series process P probe: 1. Turn the rotating dial one full turn clockwise from the window reference position (e.g., if the WRP was at 2.65 mm, turn the micrometer clockwise to 2.15 mm). 2. Next, turn the rotating dial counterclockwise one full turn plus 20 microns (2 increments on the rotating dial). (e.g., for a WRP of 2.65 mm, turn the micrometer counterclockwise from 2.15 mm to 2.67 mm) to reach the standard focal point position. To eliminate the effects of hysteresis, you must always reach the final micrometer position going counterclockwise. If you pass the required focal point position, repeat steps 1 and 2 above. Cleaning the Probe Window For the purpose of this procedure, the probe window is considered clean if counts are less than 150 per second and not repeated in a single channel when the probe tip is immersed in de-ionized (DI) water. If acetone or other solvents are required to clean the probe window, the solvent should be thoroughly rinsed away with DI water. For other applications, see the section called Cleaning the Probe Window in the hardware manual. 004-0043 Rev F Page 11 of 11