Eddy Current Technology Incorporated

EDDY CURRENT TECHNOLOGY INCORPORATED

ect MAD 8D Manual

R99119 Rev 8.1 99 NOV 09

OPERATION MANUAL

TABLE OF CONTENTS

3.0OPERATION MANUAL
3.1CALIBRATION PROCEDURE
3.1.1FREQUENCY SELECTION
3.1.2PHASE ADJUSTMENT
3.1.3GAIN ADJUSTMENT
3.1.4MIXER 1 ADJUSTMENT
3.2DATA ACQUISITION
3.2.1PREPARATION
3.2.2FORMAT THE OPTICAL DISK DRIVE
3.2.3DIRECTORY FILENAME
3.2.4LOG ONTO THE DATA DIRECTORY
3.2.5ENTER TUBE NUMBER
3.2.6RECORD DATA
3.3USE OF MOUSE
3.4PLUGGING CRITERIA
3.4.1PLUGGING CRITERIA
3.4.2CRACKS
3.4.3EROSION PITS
3.4.4CORROSION
3.4.5 GENERAL
4.0UTILITY SOFTWARE
4.0.1TUBELIST
4.0.2TUBELIST.WK1
4.0.2.1SAMPLE ECT.LST FILE
4.0.3 IMAGE.EXE
4.0.4ect ERASE.EXE
5.0OTHER INFORMATION
5.1LIBRARY FILES
5.1.1SETTINGS FILES
5.1.1.1304-50
5.1.1.290-10-44
5.1.1.390-10-55
5.1.1.4ALBRAS50
5.1.1.5ECTLAST
5.1.1.6INCOLY44
5.1.1.7 INTERFAC
5.1.1.8 TITANI22
5.1.2 EDDY CURRENT DATA LIBRARY
5.1.2.1 90/10 COPPER NICKEL ASME CALIBRATION TUBE WITH .055 WALL
5.1.2.2 C-SCAN DATA SAMPLES
5.2EDDY CURRENT DATA FORMAT
5.2.1FILE NAME
5.2.2DATA FORMAT
6.0 TEST PROCEDURE FOR ECT MAD 8D SERIES EDDY CURRENT INSTRUMENTS
6.1 SCOPE
6.2 APPLICABLE DOCUMENTS
6.3RECOMMENDED TEST EQUIPMENT
6.4PROCEDURES ~ GENERAL
6.4.1FREQUENCY
6.4.2VERTICAL AND HORIZONTAL LINEARITY
6.4.3CRT TRACE ALIGNMENT
6.4.4OUTPUT VOLTAGE OF THE RECORDER
6.4.5SPEED
6.4.6EQUAL GAIN
7.0 PREPARING ISIS FOR MAD 8D

INDEX
Reference Manual

FORMATTING OPTICAL MEDIA
2.3 GByte Magneto-Optical Disk
128 MByte Magneto-Optical Disk
230 MByte Magneto-Optical Disk
640 MByte Magneto-Optical Disk
Formatting Optical Media - 4.6 GByte Magneto-Optical Disk
800 MByte WORM Drive


3.0 OPERATION MANUAL

The operation portion of this manual provides recommended procedures for the efficient operation of the ect MAD 8D Eddy Current System.


3.1 CALIBRATION PROCEDURE

This procedure provides a recommendation for calibrating the ect MAD 8D Eddy Current System for inspection of nonferromagnetic heat exchanger tubing. This procedure could be used for any eddy current instrument or any tube material. This procedure gives information specific to the application of inspecting .875 dia. by .055 wall 90/10 copper nickel tube.

Channels 1 and 2 will be set to a high and low frequency and set to the differential mode. These two channels will be mixed in Mixer 1 to supply signals free of support plates. Channel 3 will be set to the absolute mode. Channel 3 will be used for general wall thinning measurement. Channel 4 will be set to the differential mode set to low frequency and may be used for internal pit depth measurement.

3.1.1 FREQUENCY SELECTION

The frequencies can be selected from the tabulated calculation for the Value F Table, which is given in the Electrical Conductivity of Materials Report published by Eddy Current Technology Incorporated. In this application, choose the frequency for the alloy 90/10 kHz given under the column for .056 inch thickness. Here you will see the frequency is 22 kHz. Set Channel 2 to this frequency and set Channel 1 to two times this frequency, 44 kHz. The absolute channels will be set to frequencies 10% below these. Set Channel 3 to 40 kHz and Channel 4 to 20 kHz (or 10 kHz).

Select a suitable probe. For example, an ect 5048.40 .740 DS 50 kHz probe would be suitable.

Note that Channel 1 was chosen to be exactly two times the frequency of Channel 2 and further note that Channel 3 was chosen to be exactly two times (or four times) the frequency of Channel 4. The selection of frequencies such that frequencies are in harmonic relationship results in the best performance.

3.1.2 PHASE ADJUSTMENT

Adjust the phase control for all frequency channels, such that a dent signal from the calibration tube is horizontal.

If a dent is not available in the calibration tube then an alternate (and less accurate method) will be to adjust the phase control for all frequency channels such that a lift off signal is horizontal. Do this by positioning the probe near the end of the tube, but with the differential coils well within the tube. Wiggle the probe in the tube and observe the lift off signal on the screen. Adjust the phase control until this signal is horizontal.

Pull the probe past the through wall hole in the ASME calibration tube. Confirm that the signal goes down and to the right first as the probe is pulled past the hole. If the signal goes up and to the left first, then change the applicable phase control by 180 degrees. This may be done by typing P to activate the control, and then typing the Page down key twice. Each time the Page down key is typed, the angle is changed by 90 degrees.

3.1.3 GAIN ADJUSTMENT

Pull the probe past the hole in the ASME calibration tube and adjust the throughwall hole for a peak-to-peak amplitude of approximately 2 Volts. Note that the amplitude may vary each time the probe is pulled past the hole, depending upon the distance between the probe and the defect.

If it is necessary to measure very large amplitude tube defects in the calibration tube it may be necessary to use a less sensitive gain control setting. If it is necessary to detect very tiny signals in the tube it may be necessary to use a higher gain control setting.

If small heat exchangers are being inspected such that the data from more than one heat exchanger will be saved on one disk then it is necessary to have subdirectory filenames. Choose a suitable filename, for example, if inspection unit 1, feedwater heater number 2, a suitable filename may be 1HTR2. In this case the data directory filename will be D:\1HTR2\.

It is recommended not to use a subdirectory named for saving the data. In this case, in the Setup Menu, the data directory filename should appear as D:\.

3.1.4 MIXER 1 ADJUSTMENT

Adjust Mixer 1 to eliminate the support plate signal in accordance with 2.2.0.2, Automatic Cancellation, and 2.2.0.3, Output Phase Adjustment, of the ect MAD 8D Manual.


3.2 DATA ACQUISITION

The object of data acquisition is to systematically collect eddy current data from tubes being inspected and saving the data on disk.

3.2.1 PREPARATION

In preparation for collecting data, it is necessary to format the disks that will be used and to supply suitable directory names for the data to be collected. Normally, data will be stored on an optical disk drive, which may be Drive D.

3.2.2 FORMAT THE OPTICAL DISK DRIVE - See Appendix for Instructions

3.2.3 DIRECTORY FILENAME

For large inspections in which data will be saved on several optical disks, it is recommended that directory names not be used as they are not necessary. If smaller heat exchangers are being inspected such that several heat exchangers will be saved on one optical disk, then it is recommended that directory names be used.

Select a directory name related to the equipment to be inspected. From the DOS prompt, log Drive D by typing D:\ <Enter>. Then create the desired subdirectory name by typing MKDIR Directory name <Enter>.

3.2.4 LOG ONTO THE DATA DIRECTORY

Start the ect MAD 8D eddy current software and enter the Setup Menu. Type a D in order to log the selected data directory. For example, if directory names are not being used, but data is being stored on the optical disk, then type D. After typing the D you will be prompted for the new directory name. Type D: <Enter>. The software now confirms the existence of directory D and logs that as the directory that all tube data will be stored in.

If you are using disk directories to save eddy current data, then type D. After typing D you will be prompted for the directory name. Type D:\directory name <Enter>.

Quit to the Main Menu.

3.2.5 ENTER TUBE NUMBER

From the Main Menu type DT to select the tube number for editing. Set the row, tube, and zone number to the next tube to be inspected.

3.2.6 RECORD DATA

When beginning to record tube data, press F8 to erase the contents of RAM.

You are now ready to begin recording data. When the probe is positioned at the beginning of the tube to be inspected, press F3 and begin pulling the probe through the tube. When the probe comes to the end of the tube, press F7. You will be prompted to confirm the save to disk of X.X seconds of data. Scan number Y of tube, followed by the logged row, tube and zone number. If you have the correct row, tube, and zone number entered, then type a Y and the data will now be transferred to the disk.

Change the row, tube, or zone number to indicate the next tube to be inspected. Most often this will involve using the right arrow key to increment the tube number. You are now ready to begin recording data from the second tube. When the probe is positioned and ready to go, press F7 to restart the record cycle.

The record cycle is normally implemented by pressing F3 to begin recording and then pull the probe through the tube. Then press F7, followed by a Y, to transfer the data to the disk, and a right arrow key to increment the tube number.


3.3 USE OF MOUSE

A mouse can be used with the analyze software to point to defects to analyze.

The mouse functions in the Analyze Menu when in playback/stop mode. Use 2SC,2XY or 2XY,2SC or 1XY,3SC screen modes.

Press and hold the left button of the mouse. Point to the signal you wish to analyze on a strip chart screen. The software examines the signal where you are pointing and identifies the two points furthest apart close to where you are pointing. Cursors are used to mark these points, and the signal is analyzed based on the angle and voltage in the channel selected for analysis.


3.4 PLUGGING CRITERIA

Heat exchanger tubing plugging criteria should be established by the power plant. Plugging criteria is dependent upon the tube alloy, surface conditions, flaw mechanisms, and plant requirements.

Different alloys corrode and crack and different rates. For example, soft alloys such as Aluminum Brass has one of the highest erosion rates of materials in common use in power plants. Hard alloys such as Titanium rarely erode, with the exception of steam impingement. Alloys such as Aluminum Brass rarely crack, but cracking is the major failure mechanism of Titanium. Stainless Steels with minute impurities maybe highly prone to corrosion in a sea water environment. For example, Aluminum Brass alloys have been known to develop I.D. erosion dents where shellfish have become logged in the tube. These pits grow through the tube wall in less than 1 year.

Alloys subject to cracking have crack growth rates that are very fast. Under the right conditions, Titanium tube has been known to develop circumferential cracks midspan between support plates that grow to 100% in a few hours.

Titanium tubes are rarely susceptible to corrosion. Aluminum Brass tubes in an environment in which ammonia is used for oxygen control have been known to develop ammonia induced condensate corrosion adjacent to support plates. This damage mechanism can be tracked accurately over the several years that it may take this type of damage to penetrate the wall. However, it is possible to operate the plant in a manner that this corrosion will stop.

Plugging criteria is best established by a team of engineers. The team should include a corrosion engineer and a metallurgical engineer who together understand the failure mechanisms of tubes. The team should include an eddy current specialists who understands the capabilities and limitations of the eddy current test method. The team should involve plant operational engineers who understand the requirements of the plant.

Plant requirements may impact on plugging criteria. For example, if a single isolated defect is identified in an inspection and the plant is relatively new, then this tube may as well be plugged as a precautionary measure to prevent the possibility of an unexpected leak in the near future. On the other hand, in an older plant it has often been desirable to increase the percent wall loss criteria used for tube plugging in order to keep the maximum number of tubes in service until the next shut down. This normally occurs next to the end of the heat exchanger life when the power plant is trying to operate at full capacity for an additional year until they can obtain a replacement heat exchanger or replacement tube material.

3.4.1 PLUGGING CRITERIA

Eddy Current Technology Incorporated offers the following information. This information is based on plugging criteria that the company has seen adopted by different power plants. Eddy Current Technology Incorporated assumes no liability for this information and makes no claim about its accuracy or usefulness.

3.4.2 CRACKS

As cracks often grow rapidly most power plants have decided to plug any detectable cracks regardless of depth.

3.4.3 EROSION PITS

Normally the source of erosion can be identified and stopped. For example, blockages in the tubes from shellfish or wood chips can be removed. High internal velocities which result in the end erosion can be resolved by adjusting the flow rate of cooling water in order to stop the erosion process. Erosion caused by an obstruction at the inlet to the tube such as from epoxy coatings on the support plate can be removed. Once the source of the erosion has been removed it can be assumed that the erosion process will stop and the tube need not be plugged with almost no regard to defect depth.

3.4.4 CORROSION

The cause of corrosion is more difficult to stop than the cause of erosion. Corrosion pit depth can be monitored year after year. Tubes should be plugged as pits approach a through wall condition.

3.4.5 GENERAL

Power plants have used plugging criteria that vary between 40% through wall to 80% through wall. 40% through wall is too conservative in most situations with the exception of cracks. Plugging criteria of 50 - 60% appear more common. A plugging criteria of 80% is only acceptable in a situation such as the pit being caused by erosion and the source of the erosion has been remove. Another situation in which an 80% plugging criteria may be acceptable is when the damage mechanism is known to grow relatively slowly and the plant is attempting to keep as many tubes in service as possible until the heat exchanger can be repaired. Under these circumstances the plant much anticipate occasional tube failures that will require the unit to be brought off line for plugging.


4.0 UTILITY SOFTWARE

Programs are available which work within the DOS environment to provide additional support features.


4.0.1 TUBELIST

The program TUBELIST.EXE is normally located in the MAD8D subdirectory. This utility scans a subdirectory containing stored eddy current data and makes a list of all zone, row, and tube numbers that are in that subdirectory.

From the DOS prompt type TUBELIST <Enter> and you are prompted with:

Source Directory?

Enter your source directory including drive specifier. For example, enter:

C:\ECTDATA <Enter>

The software then scans this drive and prepares a list of all the tubes it finds in this drive. The list is left in a file by the name of TUBELIST.LST. This list is in the format necessary for the Previous and Next feature in the Zone Row Tube Menu. This serves as a convenient way of making a list of the tubes on a disk which can be followed as each tube is analyzed.

This software will write over any file by the same name which was made previously and remains in the directory in which the TUBELIST.EXE file is located.

The list will be in no particular order, but may be in the order in which the data was saved. If there is more than one scan of a tube in the directory, then the tube will be listed more than once.

4.0.2 TUBELIST.WK1

The file TUBELIST.WK1 is a source file intended to be used by Borland Quattro Pro or Lotus 1-2-3 software. This file provides the format for a tubelist to be used by the Previous/Next feature of the ect MAD 8D software.

The format for the tubelist to be used by the Previous/Next feature of the ect MAD 8D software requires there to be 16 characters for each unique zone row tube number (including the Carriage Return Line Feed at the end of the line). Each line has three fields, each of which is a 3 digit number in the range of 0-255 followed by a space for the zone, row, and tube number in that order. The next two characters are ignored, but must be present. In TUBELIST.WK1 these are a space followed by an asterisk. When Quattro Pro or 1-2-3 prints the list to an unformatted file (found in the printing option of the Print to File Menu), a Carriage Return Line Feed is entered on each line, resulting in 16 characters per line. From the Worksheet Menu, select Column and then Set Width. Change the column width of columns A through D to 4.

Enter the Zone numbers in column A.
Enter the Row numbers in column B.
Enter the Tube numbers in column C.
Enter a space followed by an asterisk in column D.

From the Print Menu, select File and enter a list name with a .LST extension. Select the range of data to print from the first entry in column A to the last entry in column D. Next, select the Options Menu and set the margins. The left margin should be set equal to zero as well as the top and bottom margins. The right margin should be greater than 16. From the Options Menu, select Other and then select Unformatted. The file is now ready to be printed to disk.

4.0.2.1 SAMPLE ECT.LST FILE

 ZONEROW TUBE *   1   1   1  *    1   1   2  *  10  10  10  * 255 255 255  * 

Note that the first line is a title: ZONE ROW TUBE *. The words used for the title are not important, but the row of 14 characters plus Carriage Return Line Feed, for a total of 16.

4.0.3 IMAGE.EXE

This utility is used to recall an image file that was saved on disk by typing the F5 key in the ect MAD 8D Software as described in Section 2.6.5.

To retrieve the saved image file, start and run the image software by typing IMAGE at the DOS C:\MAD8D> prompt. Press any key to continue; then type R to retrieve file name. Enter the complete 8 character file name; for example, use 0101010X to retrieve an image saved for zone 1, row 1, tube 1. The software automatically appends the .ECI extension and then retrieves the image from disk.

To retrieve a different image, hit any key to activate the Image Menu and enter the file name as above. Please note that the image files are saved on the hard drive in a subdirectory ECTDATA. The subdirectory ECTDATA must be on the hard drive.

IMAGE.EXE is not copy protected. This allows the user to copy IMAGE.EXE plus image files (*.ECI) to other computers for display. IMAGE.EXE checks the subdirectory C:\MAD8D as well as the default directory when searching for files. This makes it possible to have IMAGE.EXE and IMAGE files in the root directory of drive A or B (any floppy drive) and the software will find the appropriate files.

4.0.4 ect ERASE.EXE

The program ect ERASE.EXE is normally located in the MAD8D subdirectory. This utility is used to erase eddy current data which has been saved on drive C: by ect MAD 8D Software. The .ECD files which are saved on disk are saved in the subdirectories which are named by the ect MAD 8D Software which are in one common subdirectory named by the operator. The lower level subdirectories named by the MAD 8D Software are R00,R01...R09, R0A, R0B..RFF. These subdirectories are in the subdirectory named by the operator. The ect erase utility prompts for the name of the subdirectory and then searches for each of the lower level subdirectories generated by the ect MAD 8D Software. It then erases all files in each of these subdirectories found, and then removes the subdirectory from the disk.

Obviously, one should use this software with Caution.

To run the software, type ECTERASE <Enter> from the MAD8D subdirectory. You are prompted for the directory name to be erased. Enter that directory name. If the data you wish to erase was stored in the root directory, then enter a "\" as the file name.

After entering the directory name, a warning message is given on the screen. To confirm erase, retype the directory name and press enter. Caution: After pressing Enter all the *.ECD files in the specified directory will be erased and the named subdirectory will also be erased unless there were files in the subdirectory. This software does not erase files in the subdirectory named by the operator in order to prevent accidental erasure of other data. To remove the named subdirectory it may be necessary for the operator to do this with standard DOS commands. (See your DOS Manual for commands ERASE and RMDIR).


5.0 OTHER INFORMATION


5.1 LIBRARY FILES

The ect MAD 8D software includes certain library files of two main categories:

1. Instrument setting files with calibration tables.
2. Eddy current data files.

5.1.1 SETTINGS FILES

The ect MAD 8D software comes with a library of eddy current instrument settings for different applications. These files may be in the ECTLIB directory or the ECTSET directory in the root directory of C: drive, or will be in directories of these names with the supplied software disk. Normally duplicate copies of these files appear in both ECTLIB and ECTSET. ECTLIB is intended to be a location for the permanent storage of these files. ECTSET contains working copies of these files. ECTSET is the default directory that the ect MAD 8D software uses for locating and storing settings files. As these are easily changed, the original copies are also kept in the ECTLIB directory on the hard disk drive.

For each application there are two files:

1) The control settings, FILENAME.ST2
2) The calibration table,FILENAME.CTB.

A list of the filenames and their applications appear below.

5.1.1.1

304-50
ect MAD 8D eddy current instrument settings for a 304 stainless steel tube with .050 (inches) wall.

5.1.1.2

90-10-44
ect MAD 8D eddy current instrument settings for a 90/10 copper nickel tube with .044 wall.

5.1.1.3

90-10-55
ect MAD 8D eddy current instrument settings for a 90/10 copper nickel tube with .055 wall.

5.1.1.4

ALBRAS50
ect MAD 8D eddy current instrument settings for an aluminum brass tube with .050 wall.

5.1.1.5

ECTLAST
A spare ECTLAST file.

5.1.1.6

INCOLY44
ect MAD 8D eddy current instrument settings for an incoloy tube with .044 wall.

5.1.1.7

INTERFAC
ect MAD 8D eddy current instrument settings for playback of analog data from other sources through the ectMAD 8D Eddy Current System.

5.1.1.8

TITANI22
ect MAD 8D eddy current instrument settings for a titanium tube with .022 wall.

5.1.2 EDDY CURRENT DATA LIBRARY

Some sample eddy current data files will be in the R01 subdirectory of theECTDATA subdirectory and may also appear in the R01 subdirectory of the ECTLIB subdirectory on drive C. These files may also appear on the supplied software disk. There are two main sources of these data files.

5.1.2.1 90/10 COPPER NICKEL ASME CALIBRATION TUBE WITH .055 WALL

These are stored as zone 1 row 1 tubes 1, 2 and 3. Tube 1 is the ASME calibration tube. Tube 2 is the ASME calibration tube with a support plate near one of the defects. Tube 3 is a scan of the support plate signal only.

5.1.2.2 C-SCAN DATA SAMPLES

These appear as zone 5, row 1, tube 1, and zone 5, row 1, tube 5. In both cases these are scans of a bolt hole calibration block with two quarter round flaws. The quarter round flaws have diameters of .050 inches and .015 inches. These flaws are located at the ends of the bolt holes.

To view this data set the ect MAD 8D in the C-Scan mode, and set the volts/div switch of Channel 1 to 2 Volts/Div. In the Analyze Menu set the threshold to 8. Enter the Zone Row Tube Menu to select zone 5, row 1,tube 1, or 5, and recall the data by pressing F6 and typing Y. The C-Scan data will now be displayed on the screen if your software includes the optional C-Scan Software.


5.2 EDDY CURRENT DATA FORMAT

This section describes the format for eddy current data stored on disk by the ect MAD 8D software when not using data compression.

5.2.1 FILE NAME

The first two characters of the file name are the zone number in hexadecimal format with possible values from 00H to FFH. The third and fourth bytes of the file name will be the row number. The fifth and sixth bytes of the file name is the tube number. The seventh byte is the scan number in hexadecimal from 0H to FH. The eighth byte is X. The dot extension is .ECD.

5.2.2 DATA FORMAT

The first two hundred bytes saved to the file name is a table which contains information about the eddy current instrument settings at the time the data was saved. This is not eddy current data and should be discarded.

Starting with the 200th byte, the raw eddy current data appears on disk in 16 byte blocks. The 16 byte block contains 8 numbers made up of 2 bytes that range from -2048 to +2047. The first pair of bytes is the value for Channel 1 Horizontal. The least significant byte is stored first; the most significant byte is stored second. The most significant 4 bits of the most significant byte will always be zero or F.

The value of 0000H corresponds to 0 volts which is the center of the screen. The highest value is 07FFH which corresponds to +8 volts. The lowest value is F800H which corresponds to -8 volts. One bit corresponds to .004 volts;(actually 8/2048 volts = 3.91 millivolts).

After the two byte horizontal value, the Channel 1 Vertical value is the next two bytes on disk. The vertical value is stored in the same format as the horizontal value except that the vertical value is multiplied by -1 before being stored.

After the horizontal and vertical values for Channel 1, the next two bytes are Channel 2 Horizontal followed by a two byte value for -Channel 2 Vertical. The values for Channel 3 Horizontal and -Vertical and Channel 4 Horizontal and -Vertical appear as the next 8 bytes to complete the first 16 byte block. Additional 16 byte blocks follow and correspond to the horizontal and vertical values taken each sample.

The following is a diagram showing the data layout.

0 . . . . . . . . .. 199 | 200. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 |

200 Byte Table H1 -V1 H2 -V2 H3 -V3 H4 -V4
. . . Repeats in 16 byte blocks

H1 Values:
0 = 0 Volts
4095 or F800H => - 8 Volts
7FFH => + 8 Volts
1H => .004 Volts
FFFFH => -.004 Volts
1 LSB = 8/2048 Volts = 3.91 mv


6.0 TEST PROCEDURE FOR ECT MAD 8D SERIES EDDY CURRENT INSTRUMENTS


6.1 SCOPE

This document is the acceptance test procedure used to insure that the ect MAD 8D Series Eddy Current Equipment is performing in accordance with the manufacturer's specifications over the frequency range from 55kHz to 4 MHz and to insure that the ect MAD 8D Series Eddy Current Equipment is performing in accordance with ASME Boiler and Pressure Code, Section V, Article I-31; Equipment Specifications.

The required test equipment is listed. The procedure is specified. and an acceptance test record form (ATR)is available upon request.

This document is applicable to all ect MAD 8D Eddy Current Instruments and to the ect PC1 MKII Printed Circuit Board.

This document does not provide the diagnostic procedures.


6.2 APPLICABLE DOCUMENTS

ASME Section V, Article I-31.


6.3 RECOMMENDED TEST EQUIPMENT

The following is a list of the recommended test equipment to be used in this procedure. Equipment with similar accuracy specifications may be substituted.

To ensure that the calibration is traceable to NBS, Item DM501A, the digital multimeter and Item DC503A, the digital counter must have a valid calibration certification traceable to NBS. Other test equipment is not used for making measurements and therefore, need not have traceable certifications.


6.4 PROCEDURES ~ GENERAL

This procedure must be repeated for each ect MAD 8D Frequency Channel or each ect PC1 MKII Printed Circuit Board.

Use the ect MAD 8D Software. Set the screen mode to 1XY, type S for screen, and left or right arrow keys to select the channel to be tested. Start with Channel 1 and repeat Section 6.4.1 to 6.4.6 for all other channels.

Connect the 50 ohm test load to the channel under test using a differential 4 pin to 9 pin adaptor cable and set the switch to the open position.

Initial Settings:
Record Mode
Frequency = 55 Hz
Phase = 0
Gain = 90
Volts Per Division = 2
LP Filter = 135
Angle Amp = Off

Press B to Balance and E to Erase the Eddy Current Instrument.

6.4.1 FREQUENCY

Set the DC503A trigger level A to .250 Volts ± .01 Volts. Set the function to frequency A. Set all push buttons out so that the counter will trigger on a positive slope. Set the attenuater to X1, the coupling to DC, and the source to external.

Connect the DC503A Channel A to the #1 BNC connector on the 50 ohm test load. Set the timing to 1 second,so that the display will be in Hz to a resolution of 1.

Set the inspection frequency to 55 Hz. Measure the frequency and record it on the acceptance test record form. Measure and record the frequency for the following frequency settings: 100 Hz, 1 kHz, 10 kHz to 20 kHz; in 1 kHz steps, 30 kHz to 100 kHz; in 10 kHz steps, 100 kHz to 700 kHz; in 100 kHz steps, 900 kHz, 1.2 MHz, 1.8 MHz, 3.6 MHz.

Each frequency reading must be within ± 5 percent of the frequency setting. A pattern will be drawn on the screen when the inspection frequency is set to 55 Hz and 100 Hz, this is normal. Under inspection conditions, the LP Filter would be set lower in order to avoid this problem when using low inspection frequencies. Lower settings of the low pass filter may be used for this test if desired, but it is not necessary.

Set the frequency to 10 kHz. Balance and erase the eddy current instrument.

6.4.2 VERTICAL AND HORIZONTAL LINEARITY

Type B to balance and E to erase the eddy current instrument. Close the switch on the 50 ohm load and adjust the phase control so the spot has moved horizontally to the right with no vertical deflection. Adjust the gain control so the spot is positioned at the right most grid point on the horizontal axis, 3 divisions right of center. It may be necessary to open and close the switch and then erase the screen several times in order to confirm that the spot moves exactly three divisions to the left of center. Use the position controls to move the spot horizontally back to the center of the screen. Open the switch. The spot now moves approximately 3 divisions to the left side of the screen. Confirm that it has moved 3 divisions ± 5 percent (+ 9 Pixels). Record the error in pixels on the ATR.

Move the spot back to the center of the screen by typing the ">" key followed by the End Key or Arrow Keys.

Leave the switch in the open position.

Change the phase control setting by reducing it by 90 degrees. Close the switch. The spot will move up. Adjust the phase and gain controls so the spot has moved up exactly 3 divisions. It may be necessary to open and close the switch several times followed by erasing the screen in order to confirm that the spot has moved exactly 3 divisions. Use position controls to move the spot to the center of the screen; then, open the switch. The spot will move down approximately 3 divisions. Confirm that the spot has moved down 3 divisions ± 5 percent (+ 9 Pixels). Record the error in pixels on the ATR.

Disconnect the BNC cable from BNC connector #1. Reset the Gain Control to 90 and the Phase Control to 0. Move the spot back to the center of the screen by typing the ">" key followed by the End Key.

6.4.3 CRT TRACE ALIGNMENT

Balance and erase the eddy current instrument. Move the spot to the right by typing the ">" key followed by holding down the right arrow key. Move the spot so it is at the right most grid point on the horizontal axis; then, hold down the left arrow key until the spot has moved to the left most grid point on the horizontal axis. Check to make sure this line is horizontal within ± 2 degrees (the vertical shift in this line must not exceed 13 pixels from the left hand side of the screen to the right hand side of the screen). Record the error in pixels on the acceptance test form.

Balance and erase the eddy current instrument. Move the spot up by typing the ">" key followed by holding down the up arrow key. Move the spot so it is at the top most grid point on the vertical axis; then, hold down the down arrow key until the spot has moved to the bottom most grid point on the vertical axis. Check to make sure this line is vertical within ± 2 degrees (the horizontal shift in this line must not exceed 13 pixels from the top of the screen to the bottom of the screen). Record the error in pixels on the acceptance test form.

Press E for erase and the ">" key followed by the End Key to return the spot to the center of the screen.

6.4.4 OUTPUT VOLTAGE OF THE RECORDER

Connect the signal generator to the BNC connector of the 50 ohm load labeled 10K. Turn the output of the oscillator off. Balance the eddy current instrument. Turn the output from the signal generator on.

Set the frequency of the oscillator to approximately 10,050 Hz, such that a circle is drawn on the screen at a speed of 50 Hz ± 10Hz.

Tip: It is difficult to measure the frequency of the circle directly using the DC503 counter; therefore, it is recommended to connect the horizontal output of the eddy current channel to an oscilloscope. Set the oscilloscope to trigger on this wave form, such that less than one full cycle of the wave form is visible on the screen. Connect the vertical trigger output of the oscilloscope to the frequency counter to measure the frequency.

Adjust the output level control of the oscillator, such that the size of the circle on the screen is 2 divisions in diameter (4 Volts peak to peak). Adjust the position controls to center the circle in the screen.

Press F8 to erase RAM and press F3 to record several seconds of this signal in RAM. Press F7 followed by a Y to save these signals on disk. Press F8 to Erase RAM; and Press F2, Playback; and confirm that there are no signals being played back from RAM; then, press F6, Recall; followed by Y, Yes; to recall the signals from disk. Press F2 to play these back to screen and confirm that playback signals are 2 divisions in diameter (4 Volts peak to peak) ± 5 percent (+ 6 pixels). Measure and record the error in pixels on the acceptance test form.

Disconnect the cable to the 10K BNC connector on the 50 ohm load. Press F3 to enter the record mode. Balance and Erase the eddy current instrument.

6.4.5 SPEED

Press F8, Erase; followed by F3, Record. Coincidence with pressing F3, start a stop watch. Stop the stopwatch when the seconds counter in the lowest line of the menu reaches 60. Confirm that the stop watch equals 60 seconds ± 5 percent.

6.4.6 EQUAL GAIN

Balance the eddy current instrument; then, close the switch on the 50 ohm load. The spot will move to the right. Adjust the gain and phase so the spot has moved horizontally to the right 3 divisions as the switch is closed. It may be necessary to open and close the switch several times and Erase the screen in order to confirm that the spot moves to the right 3 divisions as the switch is closed. Open the switch so the spot is in the center of the screen. Connect the MAD8D output cable horizontal connector to the digital multimeter. Measure and record the voltage on the acceptance test form. Close the switch, measure and record the voltage on the test form. Also enter the difference between the two readings on the acceptance test form.

Reduce the phase control setting by 90 degrees. Open the switch. Balance the eddy current instrument and erase the screen. Close the switch. Connect the MAD8D output cable vertical BNC connector to the digital multimeter. Measure and record the voltage. Open the switch. Measure and record the voltage on the acceptance test form. Also enter the difference between these two readings on the acceptance test form. Calculate the horizontal difference divided by the vertical difference. This value must be 1 ± 5 percent.


7.0 PREPARING ISIS FOR MAD 8D

Choose EXAM DATA.
Choose DDA4 DISK OPTIONS.
Type password and hit <Enter>.
Choose DATA CHECKING.

Prompts on Data Checking:

  1. Type 2 <Enter>.
  2. Type N <Enter>.
  3. Type N <Enter>.
  4. Type N <Enter>.
  5. Type N <Enter>.
  6. Type N <Enter>.
  7. Type Y <Enter>.

Hit <ESC>.
Choose EXAM DATA MENU.
Choose DDA4 DISK OPTIONS again.
Type password and hit <Enter>.
Choose DEFINE DATA FIELDS.
Set up fields to match the data in the *.FAN file.
Hit <ESC>.
Choose DISK SPOOLER.
Choose ADD DISK FILE.
Choose correct file for heater.
Choose START.
Data will be loaded onto tubesheet map.
To exit choose DDA4 MAIN MENU.
Choose EXAM DATA MENU.
Choose TUBE MAIN MENU.


REFERENCE MANUAL

The reference portion of this manual provides a detailed description of each control function of the ect MAD 8D Eddy Current System's software.


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Updated 2012Aug29