User’s Manual 7800 Series Hysteresisgraph System Lake Shore Cryotronics, Inc. 575 McCorkle Blvd. Westerville, Ohio 43082-8888 USA E-Mail Addresses: sales@lakeshore.com service@lakeshore.com Visit Our Website: www.lakeshore.com Fax: (614) 891-1392 Telephone: (614) 891-2243 Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics, Inc.
7800 Series Hysteresisgraph System User's Manual LIMITED WARRANTY Lake Shore Cryotronics, Inc. (henceforth Lake Shore), the manufacturer, warrants this product to be free from defects in material and workmanship for a period of twelve months from the date of shipment.
7800 Series Hysteresisgraph System User's Manual TABLE OF CONTENTS Chapter/Paragraph Title Page 1 INTRODUCTION.....................................................................................................................................................1-1 1.0 GENERAL.................................................................................................................................................1-1 1.1 PRODUCT DESCRIPTION ............................................................
7800 Series Hysteresisgraph System User's Manual TABLE OF CONTENTS (Continued) Chapter/Paragraph Title Page 4.1.6.2 Data Processing...............................................................................................................................4-14 4.1.6.3 Permeance.......................................................................................................................................4-16 4.1.7 Security Menu........................................................................
7800 Series Hysteresisgraph System User's Manual LIST OF ILLUSTRATIONS Figure No. 1-1 2-1 2-2 3-1 3-2 3-3 3-4 3-5 3-6 3-7 3-8 4-1 Title Page Typical 7800 Series Hysteresisgraph System ..................................................................................1-1 7800 Series Block Diagram ..............................................................................................................2-2 Yoke and Magnet Conditions.......................................................................
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800 Series Hysteresisgraph System User's Manual CHAPTER 1 INTRODUCTION 1.0 GENERAL This chapter provides introductory information for the Lake Shore 7800 Series Hysteresisgraph System. Product description is in Paragraph 1.1, specifications in Paragraph 1.2, reference material in Paragraph 1.3, safety summary in Paragraph 1.4, and safety symbols in Paragraph 1.5. 1.
7800 Series Hysteresisgraph System User's Manual Hardware Features (Continued) • • • • 1.1.2 Software Features • • • • • • • • • • • 1.2 Automatic retrieval of fluxmeter and gaussmeter probe identification and calibration data from EEPROMs in the probe connectors. True bipolar power supplies with smooth, continuous transition through zero field/current. Vertical or horizontal H-frame electromagnets with variable air gap and pole face configurations, mounted on wheeled tables.
7800 Series Hysteresisgraph System User's Manual Specifications (Continued) Overall Stability – Drift Stabilization Time Initial: 2 to 3 minute drift check allowed after cited system warm-up period. Standard: Unit optimizes drift on a run-to-run basis. System Cycle Time Calibration: 1 to 2 minutes. Measurement: 20 to 100 seconds (Test-Cycle Dependent). Calibration Model 480 – Fluxmeters have NIST-traceable calibration from the Factory.
7800 Series Hysteresisgraph System User's Manual Safety Summary (Continued) Ground The Instrument. To minimize shock hazard, connect the instrument chassis and cabinet to an electrical ground. The instrument is equipped with a three-conductor AC power cable. Plug the power cable into an approved three-contact electrical outlet or use a three-contact adapter with the grounding wire (green) firmly connected to an electrical ground (safety ground) at the power outlet.
7800 Series Hysteresisgraph System User's Manual CHAPTER 2 THEORY OF OPERATION 2.0 GENERAL This chapter provides a theory of operation relating to the operation of the Lake Shore 7800 Series Hysteresisgraph System. An introduction is provided in Paragraph 2.1, theory of operation in Paragraph 2.2, and yoke and magnetization conditions in Paragraph 2.3. 2.
7800 Series Hysteresisgraph System User's Manual Theory of Operation (Continued) The Lake Shore 7800 Series Hysteresisgraph measures and characterizes the DC properties of a variety of magnetically “hard” permanent magnet materials. Materials that can be tested with the 7800 Series Hysteresisgraph include: • Alnico. • Hard ferrite. • Neodymium-iron-boron. • Samarium cobalt. • Other hard magnetic materials in any bulk form including cast, sintered, and bonded compounds. • Compacted magnetic powders.
7800 Series Hysteresisgraph System User's Manual 2.2 THEORY OF OPERATION For an in-depth theory of the measurement of flux and flux density by a Fluxmeter or a Gaussmeter, please refer to the respective Lake Shore Model 480 Fluxmeter and Model 450 Gaussmeter User's Manuals. A DC permanent magnet hysteresisgraph is a device, which obtains the basic magnetic properties of a material by determining its magnetic hysteresis loop.
7800 Series Hysteresisgraph System User's Manual Theory Of Operation (Continued) Continuing to sweep through Negative H, we cross a point where the B vs. H curve crosses the H axis - where B = 0. This point is called Hc, or Normal Coercivity. Further increases in negative H will result in the (B-H) curve crossing the H axis. At this point, the sample has zero average induction. We have ‘coerced’ the domains from their earlier, mutually aligned direction, to average out to zero induction.
7800 Series Hysteresisgraph System User's Manual Table 2-1. Horizontal Distribution (Results of Equation 1) Air Gap (l) in Inches d=dia of uniform field 1 2 Pole Face 3 Dia. 4 (D) in 5 Inches 6 7 0.1 0.88 1.88 2.88 3.88 4.88 5.88 6.88 0.15 0.70 1.70 2.70 3.70 4.70 5.70 6.70 0.25 0.40 1.40 2.40 3.40 4.40 5.40 6.40 0.375 0.3934 -0.05 -0.52 0.95 0.48 1.95 1.48 2.95 2.48 3.95 3.48 4.95 4.48 5.95 5.48 0.5 -1.12 -0.12 0.88 1.88 2.88 3.88 4.88 0.75 -2.02 -1.02 -0.02 0.98 1.98 2.98 3.98 1 -3.22 -2.22 -1.
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7800 Series Hysteresisgraph System User's Manual CHAPTER 3 INSTALLATION 3.0 GENERAL The 7800 Series Hysteresisgraph System was electrically and mechanically inspected and operationally tested prior to shipment. It should be free from mechanical damage and in perfect working order upon receipt. Please read the entire 7800 Series User’s Manual before attempting to operate the system. 3.1 SITE REQUIREMENTS The Customer is responsible for site preparation.
7800 Series Hysteresisgraph System User's Manual General 7800 Series Site Requirements (Continued) 5. System Power And Ground Requirements The AC power source for the 7800 Series System must be frequency and voltage regulated and isolated from sources that may generate Electromagnetic Interference (EMI). Do not use two-wire (without ground) AC power. A single dedicated 20 A circuit breaker is sufficient for the computer and electronics console.
7800 Series Hysteresisgraph System User's Manual General 7800 Series Site Requirements (Continued) 6. Safety Train personnel in proper emergency measures such as electrical power shut off, fire department notification, fire extinguishing, and personnel and records evacuation. Here is a list of suggested personnel safety considerations: • • • • • Ground Fault Interrupter (GFI) AC circuits. Fire Extinguisher. Magnetic Field Warning Signs.
7800 Series Hysteresisgraph System User's Manual 3.1.2 Model 7804 Hysteresisgraph Site Preparations The customer is responsible for all site preparations preceding installation of the Hysteresisgraph System. In addition to the general requirements specified in Paragraph 3.1.1, the following are Model 7804 specific site preparations that must be completed before the arrival of the Lake Shore Engineer. 1. Model 7804 Shipping The Model 7804 Hysteresisgraph is shipped in 4 crates.
7800 Series Hysteresisgraph System User's Manual 3.1.3 Model 7807 Hysteresisgraph Site Preparations The customer is responsible for all site preparations preceding installation of the Hysteresisgraph System. In addition to the general requirements specified in Paragraph 3.1.1, the following are Model 7807 specific site preparations that must be completed before the arrival of the Lake Shore Engineer. See Figure 3-1 for a suggested site layout. 1.
7800 Series Hysteresisgraph System User's Manual 2. Electromagnet Site Preparation The Hysteresisgraph requires one water supply line and one return line for cooling of the electromagnet. The water connections are standard ¾-inch garden hose fittings, one female and one male. The 7-inch electromagnet requires a continuous water flow of 11.4 liters per minute (3 gallons per minute) for fullpower operation of the system.
7800 Series Hysteresisgraph System User's Manual 3.1.4 Model 7810 Hysteresisgraph Site Preparations The customer is responsible for all site preparations preceding installation of the Hysteresisgraph System. The following is a summary of the preparations which must be completed before the arrival of the Lake Shore Engineer. 1. Shipping and Receiving the Model 7810 The Model 7810 Hysteresisgraph is shipped in 4 crates. The following are shipping weights and sizes. 2.
7800 Series Hysteresisgraph System User's Manual F-480-3-1.eps 1 2 3 4 5 6 Power Line Cord No Connection No Connection To Rack Mount B Coil Connector (P/N 2693-100) No Connection IEEE Cable Assembly (Lake Shore Model 029) Figure 3-2. Lake Shore Model 480 Fluxmeter (B, B-H) F-480-3-1.eps 1 2 3 4 5 6 Power Line Cord No Connection No Connection To Rack Mount H Coil Connector (P/N 2693-100) Pin 15 = Power Supply +, Pin 16 = Power Supply – (also tie cable shield to Pin 16). All other pins are not used.
7800 Series Hysteresisgraph System User's Manual F-218-3-1.eps 1 2 3 Power Line Cord No Connection Sample/Bottom Pole Temperature Sensor (Input 1) (PT-111-KT-218 – Lake Shore P/N 2901-076) Ambient Temperature Sensor (Input 5) (PT-111-KT-218 – Lake Shore P/N 2901-076) No Connection IEEE Cable Assembly (Lake Shore P/N 029) 4 5 6 Figure 3-4. Lake Shore Model 218 Temperature Monitor LINE -10% +5% Voltage 50-60 Hz 40 VA MAX 120 WARNING FUSE DATA NO USER SERVICEABLE PARTS INSIDE.
7800 Series Hysteresisgraph System User's Manual To 480 Fluxmeter (B) Probe Input To 480 Fluxmeter (H) Probe Input H Input Sensing Coil B Input Sensing Coil Rack Mount Panel Rear View Rack Panel.eps Connector Name B Input Sensing Coil H Input Sensing Coil Front of Connector Goes To: B Input Sensing Coil Connector H Input Sensing Coil Connector Rear of Connector Goes To: 480 Fluxmeter (B) Probe Input 480 Fluxmeter (H) Probe Input Figure 3-6. Rack Mount Panel 11 HEATER FUSE 2.
7800 Series Hysteresisgraph System User's Manual 3.3 IEEE-488 INTERFACE CONNECTOR The instruments in the 7800 Series Hysteresisgraph communicate with the computer via the IEEE-488 Interface. The cables used conform with the IEEE-488-1978 standard document, which specifies a cable with 24 conductors with an outer shield. The connectors are 24-way Amphenol 57 Series (or equivalent) with piggyback receptacles to allow daisy-chaining in multiple device systems.
7800 Series Hysteresisgraph System User's Manual 3.4 IEEE-488 ADDRESS SETTINGS Use the following procedure to set or verify the 7800 Series Hysteresisgraph System IEEE-488 addresses. 1. Lake Shore Model 480 Fluxmeter (Measures B field, unit on left side of panel). a. Press the Interface key. b. Press the Enter key to skip Baud Rate screen. c. The IEEE address is displayed. Press the s or t key to select a setting of 18. d. Press the Enter key to save the new address. e.
7800 Series Hysteresisgraph System User's Manual IEEE-488 Address Settings (Continued) c. On the Configure – GPIB0 screen, ensure the GPIB Address is set as shown below: Primary = 0, Secondary = None. d. Also on the Configure – GPIB0 screen, ensure that the “Terminate Read on EOS” box is unchecked and that all the other settings are as shown above. If you made any changes, select the OK button. If you were just verifying settings, select the Cancel button. GPIB_3.bmp 3.
7800 Series Hysteresisgraph System User's Manual Instrument Setup (Continued) b. c. d. e. f. 5. 3.6 Press the Display Format key and use s or t key to select Location 3 and press the Enter key. Use the s or t key to select Input 1 and press the Enter key. Use the s or T keys to select Min. and press the Enter key. Press the Display Format key and use s or t key to select Location 4 and press the Enter key. Use the s or t key to select Input 1 and press the Enter key.
7800 Series Hysteresisgraph System User's Manual CHAPTER 4 OPERATION 4.0 GENERAL This chapter describes the operation of the 7800 Series Hysteresisgraph System Software. A description of the software screens is provided in Paragraph 4.1. Calibration is detailed in Paragraph 4.2. Finally, a suggested sequence of operation is provided in Paragraph 4.3. 4.
7800 Series Hysteresisgraph System User's Manual 4.1.1 MAIN SCREEN The main screen is defined in Figure 4-1. The measurement results are displayed along the left side of the screen, as defined in Paragraph 4.1.1.1. The quality control results are described in Paragraph 4.1.1.2. The eight buttons are defined in Paragraph 4.1.1.3. Finally, the status bar across the bottom of the main screen is defined in Paragraph 4.1.1.4. 4.1.1.
7800 Series Hysteresisgraph System User's Manual Measurement Results (Continued) User 1 User 2 Comment Reference Lot Additional Curve Info 4.1.1.2 For information only. Field provided for user defined entry. For information only. Field provided for user defined entry. For information only. Field provided for user defined entry. For information only. Field provided for user defined entry. For information only. Field provided for user defined entry. Shows expanded measurement information such as Permeance.
7800 Series Hysteresisgraph System User's Manual 4.1.2 FILE MENU The File Menu contains your typical Windows open, save, and exit commands. 4.1.3 Open Curve... Opens the “Open Curve” dialog box. Select from All Files (*.*), 7800 Setup Files (*.SET), or 7800 Curve Files (*.HYS). Open Setup... Opens the “Open Setup” dialog box. Select from All Files (*.*), Text Files (*.TXT), 7800 Setup Files (*.SET), or 7800 Curve Files (*.HYS). Save Curve... Opens the “Save Curve” dialog box.
7800 Series Hysteresisgraph System User's Manual System Setup (Continued) Mode 1 EEPROM Values Mode 1 calibration begins with retrieval of H an B coil calibration data from the EEPROMS in the probe connectors. Mode 1 is the simplest method, requires minimal user intervention, offers less chance for human error, and is unaffected by temperature change. However, it does rely on sensing coil stability.
7800 Series Hysteresisgraph System User's Manual System Setup (Continued) B Surrounding Coil + Hall Probe for H An air core sensing Probe with two coils (B and H) oriented in a side-by-side configuration. The flux from the B coil will be integrated by a single fluxmeter. H will be acquired via a Hall effect probe and Gaussmeter. B and H will be mathematically summed to form (B-H).
7800 Series Hysteresisgraph System User's Manual Calibration Setup (Continued) Calibration Reference Standard ID An informational field, used to store identification information on the B induction reference standard – often a high purity Nickel standard.
7800 Series Hysteresisgraph System User's Manual Calibration Setup (Continued) Saturate Standard Prior To Calibration The user is given the option to use the magnet yoke to saturate the calibration reference standard immediately before calibration is performed. This is important for when reference magnets are used. For Soft magnetic reference material such as high purity nickel, this is not required.
7800 Series Hysteresisgraph System User's Manual 4.1.3.4 Unit Select For maximum flexibility, the units used for data entry do not have to be the same as the units used in the display of measurement data on the main screen. Data Entry Units/Length This area selects the units of length to be used in data entry. Unit choices are millimeters (mm), centimeters (cm), meters (m), and inches (in). Calculated Units/Area, A·N, etc. This area selects the units of area, area·turns (A·N), etc.
7800 Series Hysteresisgraph System User's Manual 4.1.4 SENSING MENU (Supervisor Mode Only) The Sensing Menu consists of B, H Coils in Paragraph 4.1.4.1, Hall Probe in Paragraph 4.1.4.2, and Write to Coil EEPROM in Paragraph 4.1.4.3. These menu selections are only available when the Hysteresisgraph software is operating in Supervisor Mode. 4.1.4.1 B, H Coils The B Coil Setup window is shown below. The H Coil Setup window requires similar information. 4.1.4.
7800 Series Hysteresisgraph System User's Manual 4.1.4.3 Write To Coil EEPROM The Write to Coil EEPROM menu selection requires the user to interact with hardware outside of the computer. To perform this procedure, the user must ensure the appropriate Model 480 Fluxmeter has accurate information stored under Coil Setup.
7800 Series Hysteresisgraph System User's Manual 4.1.5 MEASURE MENU The Measure menu consists of two selections. The Run One Sample menu selection is described in Paragraph 4.1.5.1. The Run Sequence menu selection is described in Paragraph 4.1.5.2. These selections are available in both Supervisor and Operator Modes. 4.1.5.1 Run One Sample Parts of the Run One Sample dialog box change when a different Sample Geometry is selected. The common parts of the dialog box are described below.
7800 Series Hysteresisgraph System User's Manual 4.1.5.1.1 Rectangular Cross Section If your sample has a rectangular cross section, the dialog box allows you to enter the X and Y dimensions. The resulting cross section is calculated. Units are specified in Paragraph 4.1.3.4. X: Y: Magnetic Length: Cross Section: 4.1.5.1.2 Enter your measurement of the X axis. Enter your measurement of the Y axis. Enter your length measurement of the magnetic portion of your sample.
7800 Series Hysteresisgraph System User's Manual 4.1.5.2 Run Sequence The 7800 Software has the ability to automatically name a sequence of measurements. All samples measured as a group must work with a single sensing coil configuration. This dialog box is also called by clicking the Meas. Group button on the main screen. Root Name: Start Number Cancel Run Sequence: 4.1.6 Enter the root name of the measurement. In the example shown above, the root name is “Ferrite.
7800 Series Hysteresisgraph System User's Manual Data Processing (Continued) OFF No QC checking occurs. The Main Screen will not display Pass/fail or error data on this item. Lo/Pass QC checking is turned ON. Testing will result in either a Lo test result or a Pass test result. A lower test limit must be assigned. Hi/Pass QC checking is turned ON. Testing will result in either a Hi test result or a Pass test result. A higher test limit must be assigned. Lo/Pass/Hi QC checking is turned ON.
7800 Series Hysteresisgraph System User's Manual Data Processing (Continued) 4.1.6.3 Hk value Check to display Hk, the Knee Shape parameter. Kf Knee Factor Check to display Kf, the Knee Factor. SQR Squareness Check to display the squareness (SQR). User Defined Parameter 1 Check to display the User Defined Parameter 1. User Defined Parameter 2 Check to display the User Defined Parameter 2. Permeance Permeance lines (Load lines) may be drawn on the B, H graph.
7800 Series Hysteresisgraph System User's Manual Permeance (Continued) Calc Value For Each of the Extracted Parameters, the type of parameter will be labeled in this column as either slope, Bd, (B-H)d, or -Hd Pass/Fail For Each of the Extracted Parameters, this box allows the user to enter the level of Quality Control testing that is desired for the each parameter type: Lo/Pass, Lo/Pass/Hi, Pass/Hi or none.
7800 Series Hysteresisgraph System User's Manual 4.1.9 AXES DIALOG BOX The Axes dialog box is displayed when the Axes button on the main screen is selected. The units for primary and secondary axes are selected in the Units Select dialog box (Paragraph 4.1.3.4). If the Secondary Scale is turned Off, the selections on the right side of the display (shown below) are removed. 4.2 (+) B Full Scale Enter a number for the positive full scale reading to be displayed on the main screen.
7800 Series Hysteresisgraph System User's Manual Mode 1 Calibration (Continued) 1. Press the AutoCalibrate button. You will see the Begin AutoCalibrate dialog box. 2. Ensure the correct coils are connected to the H and B Input Sensing Coil connectors on the electronic console rack mount panel and the probe is connected to the Model 450 Gaussmeter. 3. Click the OK button. The software begins the sensor identification process which begins the Autocalibrate routine.
7800 Series Hysteresisgraph System User's Manual Mode 1 Calibration (Continued) 8. Ensure the Hall Probe Serial Number is displayed. This number is the EEPROM serial number stored in the connector shell of the Hall probe currently attached to the system. 9. Place the Hall probe in a zero gauss chamber and click the Zero Probe button. NOTE: You may bypass Step 9 if less than 1 day has elapsed from last zero. The “Time Elapsed Since Last Zero” date and time is displayed.
7800 Series Hysteresisgraph System User's Manual Mode 2 Calibration (Continued) NOTE: To further increase the precision of the calibration, make the distance of the air gap in the electromagnet the same as the height of the intended sample. 4.2.3 4. Click the AutoSet button to start generation of H Field in electromagnet gap. 5. When the AutoSet process is complete, click the Accept button. This ends Mode 2 calibration.
7800 Series Hysteresisgraph System User's Manual Mode 3 Calibration (Continued) 4-22 5. After waiting for the H field to settle, the software will display the accumulated drift. Click the Accept button to proceed with the Mode 3 calibration. 6. Check the power supply to ensure the ON and REMOTE indicators are illuminated. Click the OK button to turn power supply control over to the computer. 7.
7800 Series Hysteresisgraph System User's Manual Mode 3 Calibration (Continued) 8. While holding the reference standard in the center, place the B coil inside the electromagnet gap, then click the OK button. 9. Remove the reference/coil from the electromagnet, then click the OK button. 10. After waiting for the field to settle, the software will display the drift. Click the Accept button to proceed with the Mode 3 calibration. Press the Repeat B Calibration button to return to Step 7.
7800 Series Hysteresisgraph System User's Manual Mode 3 Calibration (Continued) 11. After waiting for the field to settle, the software will display the drift. Click the Accept button to proceed with the Mode 3 calibration. Press the Repeat B Calibration button to return to Step 7. 4.3 SOFTWARE OPERATION The 7800 Series Hysteresisgraph System Software operates in two modes: Supervisor Mode in Paragraph 4.3.1 and Operator Mode in Paragraph 4.3.2.
7800 Series Hysteresisgraph System User's Manual 4.3.1.3 Measurement Setup Based On Existing Setup This measurement setup assumes there are existing relevant setup files for the B Coil, H Coil, and Gaussmeter probe you are about to use. This procedure opens an existing setup 4.3.2 1. Apply power to the 7800 Series Hysteresisgraph System and launch the Hysteresisgraph software. 2. In the Security menu, select Change User Mode. Enter the password to switch to Supervisor Mode. 3.
7800 Series Hysteresisgraph System User's Manual 4.3.3 New Coil Setup File Method To create a new 7800 setup file for an existing coil probe, first select an existing setup file from the hard disk, which is similar to what you want. This file will be copied and modified to serve as a means to measure the sensitivity of the new coil. The measurement process involves performing a Type 2 (Air Flux) calibration on the new coil. Once measured, those new coil parameters will be placed into new setup file.
7800 Series Hysteresisgraph System User's Manual 4.3.3.3 Enter New Parameters 1. 2. 3. Operation Enter new Area values into the Main Menu , dialog box. a. For the B Coil, enter: (1) Coil Input Terminal: 100 kΩ. (2) Number of Turns: Actual number of physical turns for each coil. (3) Avg. Area Per Turn: B coil AREA-TURNS as determined by above methods divided by Actual Coil Turns. (4) Area Turns: B coil AREA-TURNS as determined by above methods.
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7800 Series Hysteresisgraph System User's Manual CHAPTER 5 OPTIONS AND ACCESSORIES 5.0 GENERAL This chapter provides details on the Lake Shore 7800 Series Hysteresisgraph System models, options. and accessories. Model numbers are detailed in Paragraph 5.1 and options and accessories in Paragraph 5.2. 5.1 MODELS The list of Lake Shore 7800 Series Model Numbers is provided as follows. Model 5.2 Description of 7800 Series 7804 The Model 7804 offers field strengths to 20.
7800 Series Hysteresisgraph System User's Manual OPTIONS (Continued) Model Number FCBL-6 Consult Lake Shore EMX-XX 66X Consult Lake Shore Consult Lake Shore Consult Lake Shore Consult Lake Shore 5-2 Description Of 7800 Series Options And Accessories User Programmable Coil Interconnect Cable. Has internal PROM that is programmable from the front panel of the Lake Shore Model 480 Fluxmeter.
7800 Series Hysteresisgraph System User's Manual CHAPTER 6 SERVICE 6.0 GENERAL This chapter provides general service information for the Lake Shore 7800 Series Hysteresisgraph. General maintenance precautions are described in Paragraph 6.1, exterior equipment cleaning in Paragraph 6.2, and electrostatic discharge is described in Paragraph 6.3. Contact Lake Shore for any further service information. 6.
7800 Series Hysteresisgraph System User's Manual 6.2 CLEANING Cleaning of the outer surfaces, while not important to operation of the equipment, is an aesthetic consideration for the looks of the equipment. Do not use strong, harsh detergents such as powdered cleansers or “all-purpose cleaners” for cleaning the plastic or painted parts of your equipment. You may use mild cleaners or a mild detergent soap solution. Use a soft, clean cloth to wipe the surfaces.
7800 Series Hysteresisgraph System User's Manual APPENDIX A GLOSSARY OF TERMINOLOGY accuracy. The degree of correctness with which a measured value agrees with the true value.2 electronic accuracy. The accuracy of an instrument independent of the sensor. sensor accuracy. The accuracy of a temperature sensor and its associated calibration or its ability to match a standard curve. actuator arm. Pivot arm with coil assembly on one end and read/write heads on the other end. algorithm.
7800 Series Hysteresisgraph System User's Manual bit. A contraction of the term “binary digit”; a unit of information represented by either a zero or a one.2 CalCurve™ Service. The service of storing a mathematical representation of a calibration curve on an EEEPROM or installed in a Lake Shore instrument. Previously called Precision Option. calibration.
7800 Series Hysteresisgraph System User's Manual gilbert (Gb). A cgs electromagnetic unit of the magnetomotive force required to produce one maxwell of magnetic flux in a magnetic circuit of unit reluctance. One gilbert is equal to 10/4π ampere-turn. Named for William Gilbert (1540 – 1603), an English physicist; hypothesized that the earth is a magnet. gilbert per centimeter. Practical cgs unit of magnet intensity. Gilberts per cm are the same as oersteds. Greek alphabet.
7800 Series Hysteresisgraph System User's Manual line of flux. An imaginary line in a magnetic field of force whose tangent at any point gives the direction of the field at that point; the lines are spaced so that the number through a unit area perpendicular to the field represents the intensity of the field. Also know as a Maxwell in the cgs system of units. line voltage. The RMS voltage of the primary power source to an instrument. load regulation.
7800 Series Hysteresisgraph System User's Manual pascal (Pa). The SI unit of pressure equal to 1 N/m2. Equal to 1.45 × 10–4 psi, 1.0197 × 10–5 kgf /cm2, 7.5 × 10–3 torr, 4.191 × 10–3 inches of water, or 1 × 10–5 bar. permeability. Material parameter which is the ratio of the magnetic induction (B) to the magnetic field strength (H): µ = B/H. Also see Initial Permeability and Differential Permeability. platinum (Pt).
7800 Series Hysteresisgraph System User's Manual sensitivity. The ratio of the response or change induced in the output to a stimulus or change in the input. Temperature sensitivity of a resistance temperature detector is expressed as S = dR/dT. setpoint. The value selected to be maintained by an automatic controller.1 serial interface. A computer interface where information is transferred one bit at a time rather than one byte (character) at a time as in a parallel interface.
7800 Series Hysteresisgraph System User's Manual APPENDIX B REFERENCE INFORMATION Table B-1.
7800 Series Hysteresisgraph System User's Manual Table B-2. Recommended SI Values for Physical Constants Quantity Symbol Value (SI units) Permeability of Vacuum µ0 4π x 10-7 H m-1 Speed of Light in Vacuum c 2.9979 x 108 m s-1 Permitivity of Vacuum ε0 = (µ0c2)-1 8.8542 x 10-12 F m-1 α α-1 e 0.0073 137.0360 Fine Structure Constant, µ0ce2/2h Elementary Charge 1.6022 x 10-19 C 6.6262 x 10-34 J Hz-1 1.
7800 Series Hysteresisgraph System User's Manual Table B-3.
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7800 Series Hysteresisgraph System User's Manual APPENDIX C OBTAINING MEASUREMENT REPEATABILITY C1.0 GENERAL The 7800 Series Hysteresisgraph is capable of excellent repeatability. At the same time, it is also sensitive to all the variables present in the measurement process. In order to obtain repeatability, it is necessary to eliminate variation in the measurement process. Variations will be present both during the calibration mode and the measurement mode.
7800 Series Hysteresisgraph System User's Manual C3.0 SENSORS/COIL SETS 1. 2. 3. Choose a sensor type appropriate for the testing task. a. Concentric coil designs with a surrounding B coil and dual surround H coils in a differential arrangement. (1) Tends to provide the most accurate results. (2) Most forgiving of errors in geometry issues. (3) Most accurate loop-shape properties. b. Embedded pole coils. (1) Only useful in QC applications (2) Only useful for low-energy samples such as ferrite material.
7800 Series Hysteresisgraph System User's Manual Sample (Continued) 5. (2) To eliminate this effect, it is advisable to center the sensor vertically in the electromagnet airgap. (a) This always results in the center-plane of the magnet being tested, reducing bias in the test due to manufacturing density/gradient effects. (b) Although repeatable, a bias may still be introduced in the measurement.
7800 Series Hysteresisgraph System User's Manual Pole-Tip Geometry and Condition (Continued) 3. 4. C-4 Poletip cleaning methods a. Poletips may be cleaned by using a piece of adhesive tape and drawing the adhesive side across the poleface to attract and remove any residual particles on the poleface. b. Care must be taken not to simply move the debris away from the poleface (say, on the edge of the pole) to keep this material from being redeposited on the poleface.
