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Lake Shore Model 480 Fluxmeter User’s Manual

7-4

Accessories, Coils, and Probes

7.2.2 30 cm

Field Probe

For measurements in narrow gaps or where field gradients dictate the use of a smaller coil diameter,
Lake Shore offers the 30cm

field probe. Specifications are defined in as follows. See Figure 7-2.

Area-Turns

(approx.)

30 cm

Coil Resistance

(approx.)

110



Average Coil Diameter

0.39 cm

Frequency Range

10 kHz

Operating Temp. Range

10 to 40



Input Resistance

(suggested)

100 k



DC Ranges

300mVs (100 T)

30mVs (10 T)

F-480-7-2.eps

Figure 7-2. 30 cm

Field Probe

Summary of Contents for 480

Page 1: ...al support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics Inc in these developments Methods and apparatus disclosed herein may be subject to U S Patents existing or applied for Lake Shore Cryotronics Inc reserves the right to add improve modify or withdraw functions design modifications or products at any time without notic...

Page 2: ...ranty is the only warranty applicable to the Product and replaces all other warranties or conditions express or implied including but not limited to the implied warranties or conditions of merchantability and fitness for a particular purpose Specifically except as provided herein Lake Shore undertakes no responsibility that the products will be fit for any particular purpose for which you may be b...

Page 3: ...k or any other incidental or consequential damages Use of our product implies that you understand the Lake Shore license agreement and statement of limited warranty FIRMWARE LICENSE AGREEMENT The firmware in this instrument is protected by United States copyright law and international treaty provisions To maintain the warranty the code contained in the firmware must not be modified Any changes mad...

Page 4: ... object of the declaration described above is in conformity with the relevant Union harmonization legislation 2014 35 EU Low Voltage Directive 2014 30 EU EMC Directive References to the relevant harmonized standards used to the specification in relation to which conformity is declared EN 61010 1 2010 Overvoltage Category II Pollution Degree 2 EN 61326 1 2013 Class A Controlled Electromagnetic Envi...

Page 5: ... this product may cause radio interference in which case the user may be required to take adequate measures The instrument was tested under normal operating conditions with sensor and interface cables attached If the installation and operating instructions in the User s Manual are followed there should be no degradation in EMC performance Pay special attention to instrument cabling Improperly inst...

Page 6: ...Lake Shore Model 480 Fluxmeter User s Manual C This Page Intentionally Left Blank ...

Page 7: ...2 2 3 Coil Resistance 2 7 2 2 4 Coil Temperature Coefficient 2 8 2 2 5 Coil Orientation 2 8 2 2 6 Field Uniformity 2 9 2 2 7 Lead Pickup 2 9 2 2 8 Inductance Capacitance and Self Resonance 2 9 2 2 9 Lake Shore Coils and Probes 2 9 2 3 FLUX OVERVIEW 2 10 2 4 FLUX DENSITY OVERVIEW 2 10 2 4 1 What is Flux Density 2 10 2 4 2 How Flux Density B Differs from Magnetic Field Strength H 2 11 2 5 MAGNETIC M...

Page 8: ... 2 DC Flux Measurement In Units of V s Mx or Wb 4 5 4 6 3 DC Flux Density Measurement In Units of G or T 4 6 4 6 4 Moment Measurement In Unit of Wb cm 4 7 4 6 5 Potential Measurement In Unit of A 4 8 5 ADVANCED OPERATION 5 1 5 0 GENERAL 5 1 5 1 UNITS SELECTION 5 1 5 2 COIL PARAMETERS 5 2 5 3 COIL SETUP 5 2 5 3 1 Input Resistance 5 3 5 3 2 Coil Resistance 5 4 5 3 3 Number of Turns N 5 4 5 3 4 Area ...

Page 9: ...m Setup 5 17 5 14 2 Relay Setup 5 18 5 14 3 Turning Alarm On and Off 5 19 5 15 ANALOG OUT OPERATION 5 19 5 15 1 Corrected Analog Output 5 19 5 15 2 Monitor Analog Output 5 20 5 16 EXTERNAL RESET 5 21 5 17 OPTIONAL INPUT 5 21 5 18 LOCKING AND UNLOCKING THE KEYPAD 5 21 5 19 RESETTING TO DEFAULT VALUES 5 22 6 COMPUTER INTERFACE OPERATION 6 1 6 0 GENERAL 6 1 6 1 IEEE 488 INTERFACE 6 1 6 1 1 IEEE 488 I...

Page 10: ...nsitive Components 8 2 8 3 LINE VOLTAGE SELECTION 8 2 8 4 FUSE REPLACEMENT 8 3 8 5 REAR PANEL CONNECTOR DEFINITIONS 8 4 8 5 1 Serial Interface Cable Wiring 8 6 8 5 2 IEEE 488 Interface Connector 8 7 8 6 TOP OF ENCLOSURE REMOVAL AND REPLACEMENT 8 8 8 6 1 Removal Procedure 8 8 8 6 2 Installation Procedure 8 8 8 7 EPROM REPLACEMENT 8 8 8 8 ERROR MESSAGES 8 9 8 9 CALIBRATION PROCEDURE 8 10 8 9 1 Requi...

Page 11: ... 2 Half Rack Mounting Kit 7 8 7 8 Model RM 2 Dual Rack Mount Shelf 7 8 8 1 Power Fuse Access 8 3 8 2 COIL INPUT Connector Details 8 4 8 3 PROBE INPUT Connector Details 8 4 8 4 Relays and Analog Signals Terminal Block 8 5 8 5 SERIAL I O Connector Details 8 5 8 6 IEEE 488 Rear Panel Connector Details 8 7 8 7 Location of Operating Software EPROM 8 9 LIST OF TABLES Table No Title Page 2 1 Examples of ...

Page 12: ...Lake Shore Model 480 Fluxmeter User s Manual vi Table of Contents This Page Intentionally Left Blank ...

Page 13: ...p up with the fastest magnetizing pulses Both a positive and negative peak can be captured from the same pulse The input of the Model 480 is protected against the high voltages at its input present during magnetizing Materials Analysis High resolution and low drift define the role of the fluxmeter in analytical measurement The high resolution of the Model 480 is reinforced by a low noise floor A c...

Page 14: ... Reading 0 05 mVs 0 005 mVs 0 005 mVs 0 005 mVs DC Peak Accuracy Offset 100 µVs DC Integrator Drift Gain 5 of reading 10 Vs s max rate of change DC Peak Maximum d dt 60 Vs s DC Peak Update Rate May reduce update rate to normal AC AC Display Resolution 4 digits AC Integrator Capacitance 0 1 µF nominal AC Input Resistance 100 k AC Ranges 30 mVs 3 mVs 300 µVs 30 µVs AC Resolution 0 001 mVs 0 0001 mVs...

Page 15: ...stance 1 k Connector Detachable terminal block General Ambient Temperature 15 35 C at rated accuracy 5 40 C with reduced accuracy Power Requirement 100 120 220 240 VAC 5 10 50 or 60 Hz 20 watts Size 217 mm W 90 mm H 317 mm D half rack 8 5 3 5 12 5 inches Weight 3 kilograms 6 6 pounds Approval CE Mark consult Lake Shore for availability Ordering Information Part number Description Instrument 480 Fl...

Page 16: ...ble 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 The power jack and mating plug of the power cable meet Underwriters Laboratories UL and International Electrotechnical Commission IEC safety standards Ventilation The instrument has ventilation holes in its top ...

Page 17: ...the voltage line if it were plotted on a graph against time When the input voltage changes in an irregular way integrator output cannot be calculated by simply multiplying voltage and time The integrator reacts continuously to the changing input to give an accurate area measurement C 480 2 1 eps 2 1 2 Why Integrators Are Used For Magnetic Measurement Integrators are used in magnetic measurements b...

Page 18: ...il turns is known Some characteristics of integrators are not seen in other measurements Two components dominate the behavior of an integrator its input resistance Rin and integrating capacitor Cint The expression for a voltage integrator is The product Rin Cint is called the integrator time constant but for practical purposes 1 RinCint can be considered the integrator gain A more complete express...

Page 19: ...g measurement It is important to understand the difference and the affects on measurements 2 1 5 Dielectric Absorption All capacitors exhibit a characteristic that can be described as a tendency to rebound from any fast change When capacitors are discharged to zero volts momentarily a small voltage will rise a few seconds later across the capacitor Likewise a rapid charge of a capacitor to some vo...

Page 20: ...ssing current through a coil fixture The magnetizer and coil fixture are optimized based on the magnet material and shape If the magnetizing field is not strong enough the magnet will not be fully magnetized Best cycle times and coil life are achieved when the magnetizer is operated at the minimum voltage required to attain the needed magnetic field The Model 480 provides an easy way to measure th...

Page 21: ...where V volts A meters2 B tesla N number of coil turns and t seconds 2 1 7 3 Calculation of Minimum Rise Time What is the fastest pulse allowable When the area turns NA of the coil and the desired peak field Bp are known the above equations can be used to calculate the minimum rise time tp NAB V SI units Calculations of minimum rise times are given for two standard Lake Shore probes V 60 volts and...

Page 22: ...umes that the coil inductance and capacitance are small and that the frequency band of the instrument is not exceeded Refer to Paragraph 2 2 8 for more details 2 2 COIL CHARACTERISTICS One reason fluxmeters are popular is the low cost and simple construction of sensing coils Some coils are as simple as a few turns of copper wire Coil construction gets more complicated to meet special measurement n...

Page 23: ...gy magnetizers with faster rise times can produce dangerous voltages with many fewer turns 2 2 2 Coil Size Application often dictates coil size Some low field coils may be several feet in diameter to contain enough changing flux for a measurable coil voltage Coils for high gradient fields are small as possible so the coil area does not exceed the uniform field area Coil size often limits the numbe...

Page 24: ...if coil resistance is not taken into account 2 2 4 Coil Temperature Coefficient Since coil resistance is temperature dependent care must be taken when large temperature changes are expected The temperature coefficient of resistance for copper magnet wire is 0 4 C 0 22 F For example a temperature increase of 10 C in a 1000 coil causes a resistance increase of 40 to 1040 If Rin 10 k the attenuation ...

Page 25: ...sistance of the integrator or the signal is attenuated The attenuation changes with frequency because the impedance does The equation for calculating inductance of an ideal long solenoid is where 0 4 10 7 H m N turns A area in m2 l length in m and Lcoil is in henries H Equations for flat search and Helmholtz coils are more complicated because there is no simple relationship between inductance and ...

Page 26: ...Density A magnetic field consists of flux lines Flux density is the number of flux lines passing perpendicular through a plane of unit area A The symbol for flux density is B where B A The CGS system measures flux density in gauss G where 1 G 1 Mx cm2 The SI system measures flux density in tesla T where 1 T 1 Wb m2 Flux density is important when magnet systems concentrate flux lines into a specifi...

Page 27: ...he distance between the poles This is sometimes called dipole moment j Wb m The SI system measures moment in amps times square meters Am2 and defines it as the current in a conducting loop times the area of the loop or Magnetic moment is measured to determine various performance factors of permanent magnets For example magnetization M can be calculated by dividing magnetic moment by the volume of ...

Page 28: ...meter The Lake Shore 480 fluxmeter accepts a value for coil constant only in centimeters COIL CONSTANT K I H amperes oersted amperes amperes cm cm units only Example A common Helmholtz coil might require 1 ampere to generate a 30 gauss field Thus K 1 ampere 30 oersteds 1 ampere 30 0 796 A cm 0 0419 cm 2 5 3 2 By Measurement of Amperes per Tesla Most of the comments above hold except that the relat...

Page 29: ...gth H With magnetic field strength measured with a potential coil and flux density measured by other means the second quadrant operating point of the magnet can be determined A potential coil with a fluxmeter measures the magnetic potential difference between two points on a permanent magnet The potential coil is generally a long thin solenoid The tip of the coil is placed perpendicular to the pol...

Page 30: ...Lake Shore Model 480 Fluxmeter User s Manual 2 14 Magnetic Measurement Overview This Page Intentionally Left Blank ...

Page 31: ... receipt of goods If damage or loss is apparent please notify the shipping agent immediately Use the packing list included with the instrument to verify receipt of the instrument probe and or coil accessories and manual Inspect for damage Inventory all components supplied before discarding any shipping materials If there is freight damage to the instrument file proper claims promptly with the carr...

Page 32: ...rification in Paragraph 3 3 1 power cord in Paragraph 3 3 2 and power switch in Paragraph 3 3 3 3 3 1 Line Voltage and Fuse Verification To verify proper line voltage selection look at the indicator in the window of the line input assembly Line voltage should be in the range shown in the specifications listed on the back of the instrument See Figure 3 2 If not change the line voltage selector per ...

Page 33: ...ve conductive parts Never probe near exposed live voltage Personal injury and damage to the instrument may result CAUTION Always turn off the instrument before making any rear panel Probe Input connections Lake Shore coils and probes plug into the 15 pin D type connector on the Model 480 rear panel Turn the instrument off before attaching a probe See Figure 8 3 for pin definitions When power is tu...

Page 34: ...tput Ground 3 6 1 Alarm Relay Connection The Model 480 has alarm relays high middle and low The terminal block has normally open N O normally closed N C and common contacts COM for each relay The instrument provides no power through the relays they open and close as switches relative to their common contact The contacts are rated at 30 VDC at 2 A Refer to Paragraph 5 14 for alarm operation 3 6 2 A...

Page 35: ...r beeps once 2 The display shows a message with the instrument model number 3 The display clears 4 The normal reading display appears An alarm annunciator beeper or overload OL indicator are not cause for immediate concern These conditions will likely be corrected during instrument setup An incomplete sequence error message Paragraph 8 8 or blank display may indicate a problem Check all connection...

Page 36: ...ak Hold is turned off Peak Hold Turns Peak Hold feature ON or OFF Peak Hold can be turned on for any units and for DC and AC input Press and hold to select Peak Mode Range Selects the range of input signal The ranges are fixed in volt second units but all other ranges depend on coil characteristics Drift Adjust Selects one of three integrator drift adjustments Auto DriftTrak and Manual Press and h...

Page 37: ...k keypad 4 5 GENERAL KEYPAD OPERATION There are three basic keypad operations 1 Direct Operation The key function occurs upon pressing the key Peak Reset Peak Hold Reading Reset AC DC Local and Alarm On Off operate directly when the key is pressed 2 Setting Selection Users select from a list of settings Range Drift Adjust Units Coil Select Address Alarm Setup and Baud display setting options when ...

Page 38: ...selected will appear then disappear 5 Press the Coil Setup key For this procedure we will assume an Input Resistance of 100 k Press the s or t keys until Input R 100k is displayed on the screen press the Enter key then the Escape key 6 If the coil resistance is less than 100 or is unknown the default value of 0 is acceptable and you may skip this step Otherwise press the Coil Setup key Press the E...

Page 39: ...Press the Enter key until Enter Coil R is displayed Use the numeric keypad to enter the coil resistance then press the Enter key The cursor will jump to a space before the symbol Use the or keys to select prefix _ for or k for k Press the Enter key then the Escape key 7 Press the Coil Setup key Press the Enter key until Enter Turns is displayed Use the numeric keypad to enter the number of turns t...

Page 40: ...il Setup key Press the Enter key until Enter Coil R is displayed Use the numeric keypad to enter the coil resistance then press the Enter key The cursor will jump to a space before the symbol Use the or keys to select prefix _ for or k for k Press the Enter key then the Escape key 7 Press the Coil Setup key Press the Enter key until Enter Area Turns is displayed Use the numeric keypad to enter the...

Page 41: ...the Coil Setup key Press the Enter key until Enter Coil R is displayed Use the numeric keypad to enter the coil resistance then press the Enter key The cursor will jump to a space before the symbol Use the or keys to select prefix _ for or k for k Press the Enter key then the Escape key 7 Press the Coil Setup key Press the Enter key until Helmholtz Constant is displayed Use the numeric keypad to e...

Page 42: ...Setup key Press the Enter key until Enter Coil R is displayed Use the numeric keypad to enter the coil resistance then press the Enter key The cursor will jump to a space before the symbol Use the or keys to select prefix _ for or k for k Press the Enter key then the Escape key 7 Press the Coil Setup key Press the Enter key until Potential Constant is displayed Use the numeric keypad to enter the ...

Page 43: ...are chosen Different coil parameters are needed and operating ranges change There may be only one practical units choice for a given application The units available in the Model 480 are summarized in Table 5 1 The table indicates which coil parameters are needed for each unit selection Unmarked parameters are ignored Units grouped as integrator flux or flux density share the same parameter require...

Page 44: ...Coil parameters are entered using the coil setup feature and stored as described in Paragraph 5 3 and 5 6 For applications that require frequent changing of a few different coils up to ten sets of coil parameters can be stored in non volatile memory in the Model 480 After information is stored the coil select function is used to call it up Coil parameters are entered using the coil setup feature a...

Page 45: ...n when using the 0 range Without a large input resistance the input is more vulnerable to electrostatic discharge ESD and other voltage spikes A non zero coil resistance must be entered for the Model 480 to calculate a display value at all Because of the potential for problems the 0 setting can only be entered with a press and hold operation and if the coil resistance is zero the display value wil...

Page 46: ...units If the number of turns is set to the default of 1 flux measurement values will equal integrator measurement values To enter coil number of turns continue from coil resistance entry or press the Coil Setup key and press the Enter key until the Enter Turns screen appears Enter Turns 1 00000 _Turns Use the numeric keypad to enter the number of turns N of the coil then press the Enter key The cu...

Page 47: ...5 3 6 Helmholtz Constant A Helmholtz constant of a Helmholtz coil is required for the Model 480 to make magnetic moment measurements The only available moment measurement unit is Wb cm which is a more convenient form of the more traditional Wb m The Helmholtz constant must be entered in cm for the display reading to have appropriate resolution For additional details refer to Paragraph 2 5 3 To ent...

Page 48: ...rcent Begin the set percent sequence by resetting the reading with the Reading Reset key or the peak hold value with the Peak Reset key Make a measurement of the sample magnet or place the coil in a known magnetic environment Press the Set Percent key The Enter Percentage screen will appear on the display Enter Percentage 100 000 _ Use the keypad to enter the percent value that is to be assigned t...

Page 49: ...rement units If the existing value of the coil parameter being calibrated is interfering with the measurement resolution set it to 1 using Coil Setup Make several measurements of the test magnet to assure repeatability An improper range setting or excess drift can cause difficulty in repeating measurements 5 5 2 Calibrating a Coil Begin the coil calibration sequence by resetting the reading with t...

Page 50: ... the instrument Turn power On l Push the Coil Setup key and enter all relevant coil parameters as detailed in Paragraph 5 3 This accomplished press and hold the Coil Select key You will see the following display Select With Save Coil Probe Use the or keys to select PROBE Press the ENTER key or press the Escape key to cancel and return to the normal display After the PROM is loaded with the necessa...

Page 51: ...would be 300 kG If a coil with an area turns of 1000 cm2 is used on the same range the resulting range boundary would be 30 kG If coil parameters are entered and units are selected before range is chosen the Model 480 will calculate and display the appropriate full scale range and resolution in the selected units Because of the construction of the Model 480 some over range should be expected Over ...

Page 52: ...ypad for very precise manual drift adjustment or controlled by the instrument for hands off drift adjustment The paragraphs below describe three ways to adjust drift with the Model 480 All drift adjustments must be made with no changing field present at the coil 5 9 1 Automatic Drift Adjustment The Model 480 can adjust drift by measuring the change in reading over a fixed time interval and calcula...

Page 53: ...ak works best after automatic drift adjustment has reduced drift to a low starting point The algorithm works only in DC mode For DC Peak operation the instrument should be allowed to idle in DC mode when not in use and switched to DC Peak before being used The DriftTrak algorithm continuously monitors changes in the fluxmeter reading If the changes are large the algorithm assumes an actual change ...

Page 54: ...The Model 480 can be used to measure non repetitive field changes in DC mode or repetitive field changes in AC mode These measurements are different and many sections in this chapter differentiate between DC and AC operation 5 10 1 DC Measurement Mode DC measurement are the most common type of magnetic measurement associated with fluxmeters Permanent magnet testing and sorting are often done in DC...

Page 55: ... signal is present Frequency response and noise dominate the error present in AC mode The Model 480 has a predictable frequency response which is illustrated in Figure 5 1 Sense coils also have a frequency response which can limit accuracy AC measurements can be susceptible to noise because most fields are small and require a low measurement range It may be necessary to shield environmental noise ...

Page 56: ...ration 5 11 2 Peak Hold in AC Mode During AC mode operation the peak hold feature bypasses the RMS converter The peak amplitude of a periodic wave form is believed to be more useful than the maximum RMS value The highest and lowest peak AC values not RMS values present in the AC signal path are captured and held This distinction can cause some confusion For a sinusoidal wave form the peak value is...

Page 57: ...t defaults to displaying of both peaks If both peaks are displayed the instrument update rate and peak reset time are slowed The instrument can read both peak values in about one fourth the normal update rate Peak reset time is doubled To select positive or negative peak press and hold the Peak Hold key for 5 seconds The following screen is displayed Select With Peak Mode Both Use the s or t keys ...

Page 58: ...ress the Enter key to accept the new setting or the Escape key to retain the old setting and return to the normal display If a single field reading differs from the filter value by more than the limit specified the instrument assumes an intentional change and restarts the filter at the new reading value This allows faster instrument response to changing fields than if the filter functioned continu...

Page 59: ...int magnitude only The cursor will jump to a space before the unit in this case G Use the or keys to select prefix µ m _ k or M Press the Enter key The alarm mode can be set to inside or outside Outside is the more common alarm operating mode where a low alarm state is active when the measured value is below the low setpoint and a high alarm is active when the measured value is above the high setp...

Page 60: ...y is active when the measured value is between the setpoints Relay operation ignores the Inside Outside parameter Relay terminals are located in the detachable terminal block on the rear panel of the instrument With On or Off modes the relays can be controlled manually for testing hardware or to control external devices unrelated to alarm function To set relay status press the Alarm Setup key You ...

Page 61: ...Output alternates between the positive and negative peak values 7 times a second For a steady state output either the positive or negative peak mode must be selected Instrument and coil calibrations can be taken into account making the corrected output more accurate than the monitor output The corrected output voltage is scaled to the DC reading value in DC mode the peak value in DC Peak or AC Pea...

Page 62: ...lue that results in 10 V output then press the Enter key The cursor will jump to a space before the units Use the or keys to select prefix µ m _ k or M Press the Enter key Manual In manual mode the corrected output voltage can be set directly by the user The output is set in percent of full scale where 100 corresponds to 10 V and 100 corresponds to 10 V The setting resolution on the display is 0 0...

Page 63: ... a logic high will produce a 1 interface response The signal is internally pulled up to allow operation with a simple switch closure between Pins 14 and 13 The OPTIN query can be used with IEEE 488 or RS 232C Computer Interface to verify the status of the input Allow 100 ms for an input status change to appear in the interface response 5 18 LOCKING AND UNLOCKING THE KEYPAD The Model 480 front pane...

Page 64: ...sh to reset the instrument to the default settings detailed in Table 5 2 No means you do not wish to reset the instrument When the display indicates the desired selection press the Enter key to accept it or the Escape key to exit the screen and revert to the previous mode If you select the Enter key you see the following screen Code date 02 26 99 Clear Coils No Use the s or t keys to select Yes or...

Page 65: ... Out High Point 0 00000 0 00000 ANOL Set Analog Out Low Point 0 00000 0 00000 ANOM Set Analog Out Mode 0 Default BRIGT Set Display Brightness 2 75 CODE Set Keyboard Lock Code 123 123 COILA Set Coil Area 1 00000 1 00000 cm2 COILAN Set Coil Area Turns 1 00000 1 00000 cm2N COILIN Set Coil Input Terminal 2 100 k COILKH Set Coil Helmholtz Constant 1 00000 1 00000 cm COILKP Set Coil Potential Constant 1...

Page 66: ...Lake Shore Model 480 Fluxmeter User s Manual 5 24 Advanced Operation This Page Intentionally Left Blank ...

Page 67: ...ecifications unless otherwise specified in this manual All instruments on the interface bus perform one or more of the interface functions of TALKER LISTENER or BUS CONTROLLER A TALKER transmits data onto the bus to other devices A LISTENER receives data from other devices through the bus The BUS CONTROLLER designates to the devices on the bus which function to perform The Model 480 performs the f...

Page 68: ...hese commands are divided into three groups 1 Bus Control refer to Paragraph 6 1 2 1 a Universal 1 Uniline 2 Multiline b Addressed Bus Control 2 Common refer to Paragraph 6 1 2 2 3 Interface and Device Specific refer to Paragraph 6 1 2 3 6 1 2 1 Bus Control Commands A Universal Command addresses all devices on the bus Universal Commands include Uniline and Multiline Commands A Uniline Command Mess...

Page 69: ...ments to the computer Most Device Specific Commands perform functions also performed from the front panel This section discusses Common and Device Specific commands Device Specific Commands consist of Interface Display Channel and Control Process commands Refer to Paragraph 6 3 for a list of all Model 480 interface and device specific commands 6 1 3 Status Registers There are two status registers ...

Page 70: ... this register interrupt the user only if the bits are enabled in the Standard Event Status Enable Register and if bit 5 of the Service Request Enable Register is set The Standard Event Status Enable Register allows the user to enable any of the Standard Event Status Register reports The Standard Event Status Enable command QESE sets the Standard Event Status Enable Register bits Setting a bit of ...

Page 71: ...d Installation for Visual Basic Program This procedure works for Plug and Play GPIB Hardware and Software for Windows 98 95 This example uses the AT GPIB TNT GPIB card 1 Install the GPIB Plug and Play Software and Hardware using National Instruments instructions 2 Verify that the following files have been installed to the Windows System folder a gpib 32 dll b gpib dll c gpib32ft dll Files b and c ...

Page 72: ...Lake Shore Model 480 Fluxmeter User s Manual 6 6 Computer Interface Operation Figure 6 1 GPIB0 Setting Configuration Figure 6 2 DEV 12 Device Template Configuration ...

Page 73: ... Interface Program in Visual Basic 1 Start VB6 2 Choose Standard EXE and select Open 3 Resize form window to desired size 4 On the Project Menu select Add Module select the Existing tab then navigate to the location on your computer to add the following files Niglobal bas and Vbib 32 bas 5 Add controls to form a Add three Label controls to the form b Add two TextBox controls to the form c Add one ...

Page 74: ...tor window under the Object dropdown list select General Add the statement Public gSend as Boolean b Double Click on cmdSend Add code segment under Private Sub cmdSend_Click as shown in Table 6 2 c In the Code Editor window under the Object dropdown list select Form Make sure the Procedure dropdown list is set at Load The Code window should have written the segment of code Private Sub Form_Load Ad...

Page 75: ...nd True Loop until Send button pressed gSend False Set Flag as False strCommand frmIEEE txtCommand Text Get Command strReturn Clear response display strCommand UCase strCommand Set all characters to upper case If strCommand EXIT Then Get out on EXIT End End If Call ibwrt intDevice strCommand term Send command to instrument If ibsta And EERR Then Check for IEEE errors do error handling if needed Ha...

Page 76: ...2 and terminators are CR LF 6 1 4 4 Quick Basic Program The IEEE 488 interface program in Table 6 6 works with QuickBasic 4 0 4 5 or Qbasic on an IBM PC or compatible running DOS or in a DOS window It assumes your IEEE 488 GPIB card is installed and operating correctly refer to Paragraph 6 1 4 3 Use the following procedure to develop the Serial Interface Program in Quick Basic 1 Copy c gpib pc Qba...

Page 77: ...Lake Shore Model 480 Fluxmeter User s Manual Computer Interface Operation 6 11 IBCONF EXE eps Figure 6 3 Typical National Instruments GPIB Configuration from IBCONF EXE ...

Page 78: ...pt The computer transmits to the instrument and displays any response If no query is sent the instrument responds to the last query received Type EXIT to exit the program REM INCLUDE c gpib pc qbasic qbdecl bas Link to IEEE calls CLS Clear screen PRINT IEEE 488 COMMUNICATION PROGRAM PRINT CALL IBFIND dev12 DEV12 Open communication at address 12 TERM CHR 13 CHR 10 Terminators are CR LF LOOP2 IN SPA...

Page 79: ...er a correctly spelled query without a nothing will be returned Incorrectly spelled commands and queries are ignored Commands and queries should have a space separating the command and associated parameters Leading zeros and zeros following a decimal point are not needed in a command string but are sent in response to a query A leading is not required but a leading is required 6 1 5 Troubleshootin...

Page 80: ...rface listed in Paragraph 6 3 However without the advantage of the IEEE 488 Architecture there are several limitations No Bus Control Commands apply Only QIDN and QRST Common Commands are usable Terminators are fixed to CRLF A query must be added to the end of a command string if the Model 480 must return information Over IEEE 488 the last query response is sent when addressed to talk For example ...

Page 81: ...h Visual Basic 6 0 VB6 on an IBM PC or compatible with a Pentium class processor A Pentium 90 or higher is recommended running Windows 95 or better with a serial interface It uses the COM1 communications port at 9600 Baud Use the following procedure to develop the Serial Interface Program in Visual Basic 1 Start VB6 2 Choose Standard EXE and select Open 3 Resize form window to desired size 4 On th...

Page 82: ...nt Public gSend as Boolean b Double Click on cmdSend Add code segment under Private Sub cmdSend_Click as shown in Table 6 6 c In the Code Editor window under the Object dropdown list select Form Make sure the Procedure dropdown list is set at Load The Code window should have written the segment of code Private Sub Form_Load Add the code to this subroutine as shown in Table 6 6 d Double Click on th...

Page 83: ...nts Loop Until gSend True Loop until Send button pressed gSend False Set Flag as false strCommand frmSerial txtCommand Text Get Command strReturn Clear response display strCommand UCase strCommand Set all characters to upper case If strCommand EXIT Then Get out on EXIT End End If frmSerial MSComm1 Output strCommand Term Send command to instrument If InStr strCommand 0 Then Check to see if query Wh...

Page 84: ...Basic Serial Interface Program CLS Clear screen PRINT SERIAL COMMUNICATION PROGRAM PRINT TIMEOUT 2000 Read timeout may need more BAUD 9600 TERM CHR 13 CHR 10 Terminators are CR LF OPEN COM1 BAUD O 7 1 RS FOR RANDOM AS 1 LEN 256 LOOP1 LINE INPUT ENTER COMMAND or EXIT CMD Get command from keyboard CMD UCASE CMD Change input to upper case IF CMD EXIT THEN CLOSE 1 END Get out on Exit CMD CMD TERM PRIN...

Page 85: ...ery without a nothing will be returned Incorrectly spelled commands and queries are ignored Commands and queries should have a space separating the command and associated parameters Leading zeros and zeros following a decimal point are not needed in a command string but are sent in response to a query A leading is not required but a leading is required 6 2 4 Troubleshooting New Installation 1 Chec...

Page 86: ...ut Resistance 6 27 COILKH Set Helmholtz Coil Constant 6 27 Command Function Page COILKH Query Helmholtz Coil Constant 6 28 COILKP Set Potential Coil Constant 6 28 COILKP Query Potential Coil Constant 6 28 COILN Set Coil Number of Turns 6 28 COILN Query Coil Number of Turns 6 28 COILNUM Configure Coil Number Parameter 6 28 COILNUM Query Coil Number Parameter 6 28 COILR Set Coil Resistance 6 28 COIL...

Page 87: ...hting for each desired bit Refer to the ESR command for a list of event flags Example To enable event flags 0 3 4 and 7 send the command ESE 143 term 143 is the sum of the bit weighting for each bit Bit Bit Weighting Event Name 0 1 OPC 3 8 DDE 4 16 EXE 7 128 PON 143 ESE Query the Configuration of Status Reports in the Standard Event Status Register Input ESE Returned ESE bit weighting Format nnn t...

Page 88: ...ment Input RST Returned Nothing Remarks Sets controller parameters to power up settings SRE Configure Status Reports in the Service Request Enable Register Input SRE bit weighting Returned Nothing Remarks Each bit has a bit weighting and represents the enable disable status of the corresponding status flag bit in the Status Byte Register To enable a status flag bit send the command SRE with the su...

Page 89: ...th a device dependent query may result in a reading error because the sensor needs time to stabilize Place a WAI between the sensor change and query for a correct reading Achieve the same results with repeated queries or using a Service Request but WAI is easier Send WAI as the last command in a command string followed by appropriate termination It cannot be embedded between other commands ACDC Co...

Page 90: ...arks Sets the high point of the alarm function Enter up to 6 digits with decimal point in exponential form Place decimal appropriate to range ALMH Query Alarm High Point Value Input ALMH Returned nnn nnnE nn Remarks Returns the high point of the alarm function up to 6 digits with decimal point in exponential form ALMIO Configure Alarm Trigger Outside Inside Input ALMIO out in Returned Nothing Rema...

Page 91: ...mode Enter up to 6 digits and a decimal point in exponential form Valid values are from 100 to 100 ANOCON Query Analog Out Control Value Input ANOCON Returned nnn nnnE nn Remarks Returns the percentage of full scale of the analog output in manual mode up to 6 digits and a decimal point in exponential form ANOH Set Analog Out High Point Value Input ANOH nnn nnnE nn Returned Nothing Remarks Sets the...

Page 92: ... bps specifies bits per second bps rate 0 300 1 1200 2 9600 BAUD Query Serial Interface Baud Rate Input BAUD Returned bps Format n term Remarks Returns serial interface baud rate Refer to BAUD command for parameter descriptions BRIGT Set Front Panel Display Brightness Input BRIGT bright Returned Nothing Remarks Sets the front panel display brightness 0 25 1 50 2 75 3 100 Default 2 BRIGT Query Fron...

Page 93: ... of cm2 Returns up to 6 digits and a decimal point in exponential form COILCAL Initiate Coil Calibration Input COILCAL nnn nnnE nn Returned Nothing Remarks Calibrates the attached coil using the currently measured field This command only works in units of V Wb Mx T G Wb cm or A The number part of the command is the value of the known field that is being used to calibrate the coil The coil must be ...

Page 94: ...ets number of turns for current coil in units of turns Enter up to 6 digits and a decimal point in exponential form COILN Query Coil Number Of Turns Input COILN Returned nnn nnnE nn Remarks Returns number of turns for current coil in units of turns Returns up to 6 digits and a decimal point in exponential form COILNUM Configure Coil Number Parameter Input COILNUM coil number Returned Nothing Remar...

Page 95: ...o 6 digits and a decimal point in exponential form Valid values are from 100 to 100 DACCRS Query Coarse Drift Adjustment DAC Value Input DACCRS Returned nnn nnnE nn Remarks Returns the percentage of full scale of the coarse drift adjustment DAC up to 6 digits and a decimal point in exponential form DACFINE Set Fine Drift Adjustment DAC Value Input DACFINE nnn nnnE nn Returned Nothing Remarks Sets ...

Page 96: ...y DriftTrak Threshold Level Input DRTHR Returned nnnn Remarks Queries the threshold level of the DriftTrak function This is the rate of change that will cause the DriftTrak function to stop adjusting the DACs The number returned is a 4 digit integer and is the units of µV s min DRTRAK Configure DriftTrak Function Off On Input DRTRAK off on Returned Nothing Remarks Configures the DriftTrak function...

Page 97: ...ned points Format nn term Remarks Queries the display filter points points integers 2 thru 64 In general the higher the number the longer the display settle time FWIN Configure Display Filter Window Input FWIN window Returned Nothing Remarks Configures the display filter window window 1 thru 10 The smaller the percentage the smaller the change in reading that causes the filter to restart Refer to ...

Page 98: ...panel 0 open or logic high 1 shorted or logic low PCTMUL Set Percent Multiplier Constant Input PCTMUL nnn nnnE nn Returned Nothing Remarks Sets the percent multiplier used to calculate units of percent Enter up to 6 digits and a decimal point in exponential form PCTMUL Query Percent Multiplier Constant Input PCTMUL Returned nnn nnnE nn Remarks Returns the percent multiplier constant used to calcul...

Page 99: ...in the currently selected units PKRST Initiate Peak Reset Command Input PKRST Returned Nothing Remarks Resets the peak hold circuit and the peak hold values PROBE Set Probe Serial Number and Date Input PROBE serial number date Returned Nothing Remarks Sets the serial number and date for the attached probe A probe with a PROM attachment Lake Shore part FCBL 6 is required for this function Enter up ...

Page 100: ...ns the high relay function 0 Manual Off 1 Manual On 2 Automatic RELAYL Configure Low Relay Function Input RELAYL mode Returned Nothing Remarks Configures the low relay function 0 Manual Off 1 Manual On 2 Automatic RELAYL Query Low Relay Function Input RELAYL Returned 0 1 or 2 Format n term Remarks Returns the low relay function 0 Manual Off 1 Manual On 2 Automatic RELAYM Configure Middle Relay Fun...

Page 101: ...IEEE 488 terminating character type terminator specifies the terminator 0 CR LF 1 LF CR 2 LF 3 No terminators Terminating characters are sent when the Model 480 completes its message transfer on output They also identify the end of an input message This command works only with the IEEE 488 Interface and does not change the serial terminators TERM Query Terminating Character Input TERM Returned 0 1...

Page 102: ...Lake Shore Model 480 Fluxmeter User s Manual 6 36 Computer Interface Operation This Page Intentionally Left Blank ...

Page 103: ...7 7 4 240V EU CEE 7 7 5 240V UK BS 1363 6 240V Swiss SEV 1011 7 220V China GB 1002 7 1 ACCESSORIES Accessories are devices that perform a secondary duty as an aid or refinement to the primary unit Accessories available for the Model 480 Fluxmeter are listed as follows Model Number Description 106 739 Terminal Block Mating Connector Eight pin quantity of two 4004 IEEE 488 Interface Cable Connects M...

Page 104: ...nch inside diameter 200 G 1 MRA 312 300 Axial Reference Magnet 0 312 inch inside diameter 300 G 1 MRA 312 500 Axial Reference Magnet 0 312 inch inside diameter 500 G 1 MRA 312 1K Axial Reference Magnet 0 312 inch inside diameter 1 kG 1 MRA 312 2K Axial Reference Magnet 0 312 inch inside diameter 2 kG 1 MRT 062 200 Transverse Reference Magnet 0 062 inch gap 200 G 1 MRT 062 500 Transverse Reference ...

Page 105: ... information including number of turns effective area and resistance are stored in a PROM located in the probe connector Users need only attach the probe to the fluxmeter turn on the instrument set the range and re set the zero before taking readings No manual input of coil parameters is necessary 7 2 1 100 cm2 Field Probe For years the most common field probe had 100 cm2 area turns Specifications...

Page 106: ...use of a smaller coil diameter Lake Shore offers the 30cm2 field probe Specifications are defined in as follows See Figure 7 2 Area Turns approx 30 cm2 Coil Resistance approx 110 Average Coil Diameter 0 39 cm Frequency Range 10 kHz Operating Temp Range 10 to 40 C Input Resistance suggested 100 k DC Ranges 300mVs 100 T 30mVs 10 T F 480 7 2 eps Figure 7 2 30 cm2 Field Probe ...

Page 107: ...nnector on the rear panel of the Model 480 Helmholtz coils are calibrated for use in Wb cm units Pertinent calibration information including the calibration constant and resistance are stored in Programmable Read Only Memory PROM located in the cable connector Users need only attach the coil to the Model 480 Fluxmeter turn on the instrument set the range and reset the zero before taking readings N...

Page 108: ...Lake Shore Model 480 Fluxmeter User s Manual 7 6 Accessories Coils and Probes P 480 7 4 bmp Figure 7 4 Model FH 6 Helmholtz Coil P 480 7 5 bmp Figure 7 5 Model FH 12 Helmholtz Coil ...

Page 109: ...lues ranging from 100 G to 20 kG but the most widely used value is 1 kG Reference magnets accuracy is typically 0 5 except for magnets of 200 G or less for these magnets the limit of error is generally 1 The reference magnet gap is nominally 0 060 inch but may range from 0 040 to 0 250 inch for special units The usable plateau in the reference gap generally encompasses an area of about 0 5 square ...

Page 110: ...Lake Shore Model 480 Fluxmeter User s Manual 7 8 Accessories Coils and Probes C 480 7 7 eps Figure 7 7 Model RM 1 2 Half Rack Mounting Kit C 480 7 8 eps Figure 7 8 Model RM 2 Dual Rack Mount Shelf ...

Page 111: ...ent without having another person nearby capable of rendering aid If there is no power verify the power cord is plugged into a live outlet and that both ends are securely plugged in Next check the fuse see Paragraph 3 3 1 1 Use this procedure to periodically clean the Model 480 to remove dust grease and other contaminants 1 Clean front and back panels and case with soft cloth dampened with a mild ...

Page 112: ... surface or in a conductive container An operator inserting or removing a device or assembly from a container must maintain contact with a conductive portion of the container Use only plastic bags approved for storage of ESD material 6 Do not handle ESDS devices unnecessarily or remove from the packages until actually used or tested 8 3 LINE VOLTAGE SELECTION Use the following procedure to change ...

Page 113: ...fuse WARNING To avoid potentially lethal shocks turn off controller and disconnect it from AC power before performing these procedures CAUTION For continued protection against fire hazard replace only with the same fuse type and rating specified for the line for the line voltage selected 1 Locate line input assembly on the instrument rear panel See Figure 8 1 2 Turn power switch Off O 3 Remove ins...

Page 114: ... DESCRIPTION HI LO Input Red Banana Jack Input Black Banana Jack Figure 8 2 COIL INPUT Connector Details 5 4 3 2 1 15 14 13 12 PROBE INPUT 8 7 6 11 10 9 C 480 8 3 cvs PIN DESCRIPTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Probe Coil Input Hi Analog Signal No Connection No Connection No Connection No Connection No Connection No Connection No Connection Probe Coil Input Lo Analog Signal Ground No Conne...

Page 115: ...put Signal Corrected Output Ground Figure 8 4 Relays and Analog Signals Terminal Block F 480 8 5 eps Model 480 Fluxmeter Computers and Printers DE 9P DB 25P DE 9P Pin Description Pin Description Pin Description 1 No Connection 2 TD out 1 DCD in 2 Receive Data RD in 3 RD in 2 RD in 3 Transmit Data TD out 4 RTS out 3 TD out 4 Data Terminal Ready DTR out 5 CTS in 4 DTR out 5 Ground GND 6 DSR in 5 GND...

Page 116: ...ut 1 NC 7 RTS out 7 DTR tied to 4 8 CTS in 8 NC 1 DCD in Model 480 to PC Serial Interface PC with DB 25P Model 480 DE 9P Standard Null Modem Cable DE 9S to DB 25S PC DB 25P 5 GND 7 GND 2 RD in 2 TD out 3 TD out 3 RD in 1 NC 4 RTS out 7 DTR tied to 4 5 CTS in 8 NC 8 DCD in 6 DSR in 20 DTR out 4 DTR out 6 DSR in Model 480 to PC Interface using Null Modem Adapter Model 480 DE 9P Null Modem Adapter PC...

Page 117: ...e Model 480 rear panel 11 12 10 9 8 7 6 5 4 3 2 1 23 24 22 21 20 19 18 17 16 15 14 13 IEEE 488 INTERFACE SH1 AH1 T5 L4 SR1 RL1 PP0 DC1 DT0 C0 E1 C 480 8 6 cvs PIN SYMBOL DESCRIPTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 DIO1 DIO2 DIO3 DIO4 EOI DAV NRFD NDAC IFC SRQ ATN SHIELD DIO5 DIO6 DIO7 DIO8 REN GND 6 GND 7 GND 8 GND 9 GND 10 GND11 GND Data Input Output Line 1 Data Inp...

Page 118: ...rd to rear of unit and set power switch to On l 8 7 EPROM REPLACEMENT The operating software for the Model 480 is contained on one Erasable Programmable Read Only Memory EPROM Integrated Circuit IC The reference designator for the EPROM is U53 The EPROM has a sticker on top labeled with M480 HEX and the date Use the following procedure to replace the EPROM CAUTION The EPROM is an Electrostatic Dis...

Page 119: ...t to Lake Shore for repair and recalibration Invalid Calibration Press the Escape and Enter keys simultaneously The instrument is out of calibration but can still be used Reading values can be as much as 5 off Return the instrument to Lake Shore for recalibration Drift Adjust Failed The Auto Adjust feature was not able to compensate for the drift of the instrument Make sure the coil is properly co...

Page 120: ...wave Suggested Hewlett Packard Model HP34401A 3 Oscillator 0 1 Hz to 50 kHz sine burst mode square wave amplitude accuracy 2 frequency accuracy 0 01 output impedance 50 Suggested Hewlett Packard HP33120 4 1 µF 50 V non polar mylar or polypropylene capacitor to be connected in series with the oscillator signal lead during AC calibration The actual accuracy of the capacitor is not a major issue sinc...

Page 121: ...k Pk Rng Pk Rng 30 mV s 100 k 60 Hz 5 655 Vrms 15 mV s 20 21 2 mV s 26 32 3 mV s 100 k 60 Hz 0 7540 Vrms 2 mV s 21 2 83 mV s 27 33 300 µV s 100 k 1 kHz 1 257 Vrms 200 µV s 22 283 µV s 28 34 30 µV s 100 k 1 kHz 0 1257 Vrms 20 µV s 23 n a n a n a 3 mV s 10 k 60 Hz 0 7540 Vrms 2 mV s 2 2 83 mV s 8 14 300 µV s 10 k 1 kHz 1 257 Vrms 200 µV s 3 283 µV s 9 15 30 µV s 10 k 1 kHz 0 1257 Vrms 20 µV s 4 28 3...

Page 122: ...k Calibration The following procedure is to be repeated for each range entry in Table 8 2 Table 8 2 DC Calibration Table Range Input R Freq Period Amplitude Offset Vs nom Cal Rng Pk Rng Pk Rng 300 mV s 100 k 0 1 Hz 5 sec 5 volts p p 2 5 volts 250 mV s 18 24 30 30 mV s 100 k 1 Hz 0 5 sec 5 volts p p 2 5 volts 25 mV s 19 25 31 30 mV s 10 k 1 Hz 0 5 sec 5 volts p p 2 5 volts 25 mV s 0 6 12 3 mV s 10 ...

Page 123: ...end Calibration Constant to the appropriate positive peak range location per Table 8 2 from the computer using the form CALGAIN location x xxxxxe x 23 Send the same Calibration Constant to the appropriate negative peak range location per Table 8 2 from the computer using the form CALGAIN location x xxxxxe x 24 Repeat Steps 5 thru 24 for each range of Table 8 2 until all DC ranges are calibrated 8 ...

Page 124: ...C Offset Constant using the form CALCOFF xxxxxx NOTE This value must be between 0 005 and 0 A value outside this range indicates a major malfunction of the Model 480 that requires repair 7 Send Corrected DAC Gain Constant using the form CALCGAIN xxxxxx NOTE This value must be between 0 95 and 1 0 A value outside this range indicates a major malfunction of the Model 480 that requires repair 8 9 8 F...

Page 125: ...rrent that if maintained in two straight parallel conductors of infinite length of negligible circular cross section and placed one meter apart in a vacuum would produce between these conductors a force equal to 2 10 7 newton per meter of length 2 This is one of the base units of the SI ampere turn A MKS unit of magnetomotive force equal to the magnetomotive force around a path linking one turn of...

Page 126: ...tal processor In Lake Shore controllers the heater output is maintained as a variable DC current source digital data Pertaining to data in the form of digits or interval quantities Contrast with analog data 2 dimensionless sensitivity Sensitivity of a physical quantity to a stimulus expressed in dimensionless terms The dimensionless temperature sensitivity of a resistance temperature sensor is exp...

Page 127: ...ind its cause 1 Also see magnetic hysteresis IEEE Institute of Electrical and Electronics Engineers IEEE 488 An instrumentation bus with hardware and programming standards designed to simplify instrument interfacing The addressable parallel bus specification is defined by the IEEE initial permeability The permeability determined at H 0 and B 0 initial susceptibility The susceptibility determined a...

Page 128: ...he point in question Also know as magnetic potential 1 magnetic units Units used in measuring magnetic quantities Includes ampere turn gauss gilbert line of force maxwell oersted and unit magnetic pole magnetization M This is a material specific property defined as the magnetic moment m per unit volume V M m V Measured in SI units as A m and in cgs units as emu cm3 1 emu cm3 103 A m Since the mass...

Page 129: ...ntity can be discriminated 2 display resolution The resolution of the physical display of an instrument This is not always the same as the measurement resolution of the instrument Decimal display resolution specified as n digits has 10n possible display values A resolution of n and one half digits has 2 10n possible values measurement resolution The ability of an instrument to resolve a measured q...

Page 130: ... flux measurements in units of Volt seconds V s Webers Wb or Maxwells Mx Underwriters Laboratories UL An independent laboratory that establishes standards for commercial and industrial products unit magnetic pole A pole with a strength such that when it is placed 1 cm away from a like pole the force between the two is 1 dyne vector A quantity that has both magnitude and direction and whose compone...

Page 131: ...y energy productk W erg cm3 10 1 J m3 Demagnetization factor D N dimensionless 1 4 dimensionless NOTES a Gaussian units and cgs emu are the same for magnetic properties The defining relation is B H 4 M b Multiply a number in Gaussian units by C to convert it to SI e g 1 G 10 4 T G 10 4 T c SI Système International d Unités has been adopted by the National Bureau of Standards Where two conversion f...

Page 132: ... 15 J Hz 1 C 1 Josephson Frequency Voltage Ratio 2e h 483 5939 THz V 1 Quantum of Circulation h 2me h me 3 6369 10 4 J Hz 1 kg 1 7 2739 10 4 J Hz 1 C 1 Rydberg Constant R 1 0974 107 m 1 Proton Moment in Nuclear Magnetons µp µN 2 7928 Bohr Magneton µB eh 2me 9 2741 10 24 J T 1 Proton Gyromagnetic Ratio p 2 6752 108 s 1 T 1 Diamagnetic Shielding Factor Spherical H2O Sample 1 H2O 1 0000 Molar Mass Co...

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