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Lake Shore Model 475 Gaussmeter User’s Manual 

 

 

1-2 

Introduction 

DC Measurement Mode:

 Static or slowly changing fields are measured in DC mode where the accuracy, resolution, 

and stability of the Model 475 are most evident. The gaussmeter takes advantage of the internal auto zero function and 
probe linearity compensation to provide its best accuracy in this mode. Measurement resolution is enhanced by advanced 
signal processing capability, allowing users the choice of high reading rates (100 readings per second or more) or high 
resolution (to 5¾ digits in DC mode). The Model 475 also features front-end amplification that was specifically designed 
to complement DSP data acquisition to provide high stability and repeatability. That, along with probe temperature 
compensation, makes the Model 475 the most stable gaussmeter that Lake Shore has ever produced, suiting it perfectly 
for demanding DC measurement applications such as field mapping and field control. 

 

RMS Measurement Mode:

 Periodic AC fields are measured in RMS mode, which highlights the uniquely flexible filter 

functions of the Model 475. An overall frequency range of 1 Hz to 20 kHz is offered by the gaussmeter. Selectable band-
pass and low-pass filters allow users to reject unwanted signals and improve measurement performance. Digital signal 
processing algorithms also free the Model 475 from the limitations of conventional RMS conversion hardware and 
provide better dynamic range, resolution, and frequency response than ever before. These improvements permit 
meaningful RMS field measurements with broad frequency content or in noisy environments. (Best high frequency 
performance requires proper probe selection.) 

 

Peak Measurement Mode: 

Pulsed fields are measured in Peak mode, which is a natural extension of the high-speed 

data acquisition necessary for DSP operation. Fast instrument sample rates permit capture of positive and negative field 
pulses as narrow as 20 

µ

s in width, which can be held for an unlimited length of time with no sag. This is ideal for most 

magnetizers and other fast pulse applications. For more moderate field changes, the Model 475 can process the captured 
data to create other features. The gaussmeter can be configured to follow the peak of a periodic waveform for evaluation 
of crest factor. The Model 475 can also be used to sample field changes at 1000 readings per second that can later be 
read over interface to illustrate the shape of pulses or other waveforms. 

 

The Probe Connection:

 The Model 475 is only half of the magnetic field measurement equation. For the complete 

solution, Lake Shore offers a full complement of standard Hall-effect probes in a variety of sizes and sensitivities. The 
probes are designed and built at Lake Shore to provide the maximum benefit from the advanced features of the 
gaussmeter. Each probe is calibrated to compensate for both field and temperature effects. The calibration data is loaded 
into the probe connector for hassle free interchangeability including hot swapping. Three different probe sensitivities are 
available and extend full-scale measurement ranges from 35 mG to 350 kG. Custom probes are also available from Lake 
Shore when the standard configurations do not meet all application requirements. 

 

1.1.1 

Advanced Features 

In addition, the features that users have come to expect from Lake Shore gaussmeters, the Model 475 combines elements 
of hardware and firmware to create advanced features that facilitate automation and materials analysis. 

 

Field Control:

 A built in PI control algorithm turns the Model 475 into an essential building block for magnetic field 

control in electromagnet systems. The gaussmeter and a voltage programmable magnet power supply are all that is 
needed to control stable magnetic fields in an electromagnet at the user specified setpoint. One of the built in analog 
voltage outputs is used to drive the program input of the power supply for either bipolar or unipolar operation. 

 

High Speed Data Transfer:

 The IEEE-488 interface can be configured to send readings in binary format rather than the 

more common ASCII format. This reduces interface overhead enabling real time reading rates up to 100 readings per 
second. Temperature compensation is not available at the highest interface rate. 

 

Data Buffer:

 Memory within the instrument provides storage for 1024 field readings in a data buffer. The buffer can be 

filed at high speed, up to 1000 reading per second, which is as much as ten times faster than the computer interface. 
Stored readings can then be retrieved over interface at slower speed and processed off-line. Trigger input can be used to 
initiate the data log sequence. Slower sample rates can be programmed if desired. 

 

Trigger In and Trigger Out:

 A hardware, TTL level, trigger into the instrument can be used to initiate the data log 

sequence. A hardware, TTL level trigger out of the instrument indicates when the instrument completes a reading and 
can be used to synchronize other instrument in the system. A software, IEEE-488 based trigger can be used like the 
hardware trigger in. 

Содержание 475

Страница 1: ...r 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 notice Lake Shore...

Страница 2: ...r 6 This limited warranty does not cover a regularly scheduled or ordinary and expected recalibrations of the Product b accessories to the Product such as probe tips and cables holders wire grease varnish feed throughs etc c consumables used in conjunction with the Product such as probe tips and cables probe holders sample tails rods and holders ceramic putty for mounting samples Hall sample cards...

Страница 3: ...d specifications and that this product met its published specifications at the time of shipment The accuracy and calibration of this product at the time of shipment are traceable to the United States National Institute of Standards and Technology NIST formerly known as the National Bureau of Standards NBS FIRMWARE LIMITATIONS Lake Shore has worked to ensure that the Model 475 firmware is as free o...

Страница 4: ...duct In a domestic environment 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 a probe 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 This instrument is not inten...

Страница 5: ...ration described above is in conformity with the relevant Union harmonization legislation 2014 35 EU Low Voltage Directive 2014 30 EU EMC Directive 2011 65 EU RoHS 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 Electromagneti...

Страница 6: ...ake Shore Cryotronics Inc All rights reserved No portion of this manual may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the express written permission of Lake Shore ...

Страница 7: ...RVIEW 2 5 2 2 1 What is Flux Density 2 5 2 2 2 How Flux Density B Differs from Magnetic Field Strength H 2 5 2 3 HALL MEASUREMENT 2 5 2 3 1 Active Area 2 6 2 3 2 Polarity 2 6 2 3 3 Orientation 2 7 2 4 FIELD CONTROL 2 7 2 4 1 Closed Loop PI Control 2 7 2 4 1 1 Proportional P 2 8 2 4 1 2 Integral I 2 8 2 4 1 3 Manual Output 2 8 2 4 2 Tuning a Closed Loop PI Controller 2 10 2 4 2 1 Tuning Proportiona...

Страница 8: ...4 12 4 7 1 RMS Operation Select Range and Autorange 4 12 4 7 2 RMS Operation Filter Selection 4 13 4 7 2 1 Wide Band Filters 4 14 4 7 2 2 Narrow Band Filters 4 15 4 7 2 3 Lowpass Filters 4 15 4 7 3 RMS Operation Frequency Measurement 4 17 4 7 4 RMS Operation Reading Rate 4 17 4 7 5 RMS Operation Max Hold 4 18 4 7 5 1 Max Min Display Setting 4 18 4 7 6 RMS Operation Reset 4 18 4 7 7 RMS Operation R...

Страница 9: ...ation 6 2 6 1 3 IEEE 488 Command Structure 6 2 6 1 3 1 Bus Control Commands 6 2 6 1 3 2 Common Commands 6 3 6 1 3 3 Device Specific Commands 6 3 6 1 3 4 Message Strings 6 3 6 1 3 5 Highspeed Binary Output Configuration 6 4 6 1 4 Status System 6 5 6 1 4 1 Overview 6 5 6 1 4 2 Status Register Sets 6 8 6 1 4 3 Status Byte and Service Request SRQ 6 9 6 1 5 IEEE Interface Example Programs 6 12 6 1 5 1 ...

Страница 10: ...O LAKE SHORE 8 1 8 3 FUSE DRAWER 8 2 8 4 LINE VOLTAGE SELECTION 8 2 8 5 FUSE REPLACEMENT 8 2 8 6 ERROR MESSAGES 8 3 8 7 ELECTROSTATIC DISCHARGE 8 4 8 7 1 Identification of Electrostatic Discharge Sensitive Components 8 4 8 7 2 Handling Electrostatic Discharge Sensitive Components 8 4 8 8 ENCLOSURE TOP REMOVAL AND REPLACEMENT 8 5 8 9 FIRMWARE REPLACEMENT 8 5 8 10 CONNECTOR AND CABLE DEFINITIONS 8 7...

Страница 11: ...ontrol Algorithm Standard and Custom Probes Available 1 1 DESCRIPTION The First DSP Gaussmeter Lake Shore combined the technical advantages of digital signal processing with over a decade of experience in precision magnetic field measurements to produce the first commercial digital signal processor DSP based Hall effect gaussmeter the Model 475 DSP technology creates a solid foundation for accurat...

Страница 12: ...e of pulses or other waveforms The Probe Connection The Model 475 is only half of the magnetic field measurement equation For the complete solution Lake Shore offers a full complement of standard Hall effect probes in a variety of sizes and sensitivities The probes are designed and built at Lake Shore to provide the maximum benefit from the advanced features of the gaussmeter Each probe is calibra...

Страница 13: ...connector during calibration Probe Field Compensation The Hall effect devices used in gaussmeter probes produce a near linear response in the presence of magnetic field The small non linearities present in each individual device can be measured and subtracted from the field reading Model 475 probes are calibrated in this way to provide the most accurate DC readings Probe Temperature Compensation H...

Страница 14: ...elays The relays can also be controlled manually for other system needs Voltage Output 1 The first voltage output gives access to amplified voltage signal directly from the probe This voltage is corrected for the nominal sensitivity of the probe and provides the widest bandwidth of the three voltage outputs In wideband AC mode its signal can be viewed on an oscilloscope to observe the shape of AC ...

Страница 15: ...ock hazard the instrument is equipped with a 3 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 The power jack and mating plug of the power cable meet Underwriters Laboratories UL and International Electrotechnical Com...

Страница 16: ...Lake Shore Model 475 Gaussmeter User s Manual 1 6 Introduction 1 4 SAFETY SYMBOLS ...

Страница 17: ...ement to be made on signals of up to 20 kHz The sampling and filtering in the Model 475 can allow realizable resolutions of 20 bits which is in the noise floor of the instrument 2 1 2 Digital Signal Processing Digital Signal Processing DSP is the science of manipulating digital data through the use of mathematics The variety of processing that can be done is almost endless from simulating an analo...

Страница 18: ...The Hall voltage produced by the sensor is fed back into the instrument and sent through a programmable gain stage The signal is then AC coupled into the A D where it is read at up to 50 kHz Those signals are then sent to the DSP where the signal processing is done and the readings are filtered The data is then transferred to the microprocessor where the readings can be sent to the display or out ...

Страница 19: ...frequency band Figure 2 2 DC Measurement Block Diagram 2 1 6 RMS Measurement The Model 475 offers two different modes of AC measurement narrow band and wide band In narrow band AC measurement the instrument uses a 100 mA 5 kHz square wave excitation current This type of excitation provides the benefit of noise cancellation characteristics of the product detector but limits the maximum frequency to...

Страница 20: ...ented with the addition of external filters to the analog output Figure 2 4 RMS Wide Band AC Block Diagram 2 1 7 Peak Measurement The Model 475 is capable of measuring the peak amplitudes of signals either peak pulses or periodic pulses In peak mode the instrument uses a 100 mA DC excitation current The voltage that is generated by the Hall device is read by the A D at 40 kHz The readings are then...

Страница 21: ...fusion of flux density and magnetic field strength is also related to permeability In the cgs system the permeability of air of vacuum is 1 Therefore 1 G 1 Oe or B H in air Many people incorrectly assume therefore that in the cgs system B H at all times Adding to the confusion in the SI system permeability of air is not 1 so B is not equal to H even in air 2 3 HALL MEASUREMENT The Hall effect was ...

Страница 22: ...s are made This entity is normally called a Hall plate The Hall plate is in its simplest form a rectangular shape of fixed length width and thickness Due to the shorting effect of the current supply contacts most of the sensitivity to magnetic fields is contained in an area approximated by a circle centered in the Hall plate whose diameter is equal to the plate width Thus when the active area is g...

Страница 23: ...m the power supply A Lake Shore probe is used to measure the field and completes the closed loop configuration The instrument probe power supply and magnet play important roles in establishing stable field control 2 4 1 Closed Loop PI Control Closed loop PI control often called feedback control is the control mode most often associated with field controllers In this mode the controller attempts to...

Страница 24: ...integral term also called reset looks at error over time to build the integral contribution to the output dt e I P I Output 1 By adding the integral to proportional contributions the error that is necessary in a proportional only system can be eliminated When the error is at zero controlling at the setpoint the output is held constant by the integral contribution The integral setting I is more pre...

Страница 25: ...Lake Shore Model 475 Gaussmeter User s Manual Background 2 9 Figure 2 8 Examples of PI Control ...

Страница 26: ...r P approximately 5 or 10 Set the control setpoint to some low non zero field 1 kG for example If the field is oscillating then P is too high and needs to be reduced If the field is not oscillating increase P by a factor of two until the system begins to oscillate See Figure 2 8 a Do not set the proportional setting so high that it causes violent oscillations The appropriate value for P is one hal...

Страница 27: ...low Contact Lake Shore immediately if there is a shortage of parts or accessories Lake Shore is not responsible for any missing items if not notified within 60 days of shipment Inspect all items for both visible and hidden damage that occurred during shipment If damage is found contact Lake Shore immediately for instructions on how to file a proper insurance claim Lake Shore products are insured a...

Страница 28: ...rd receptacle instrument power switch and line voltage selector with line voltage indicator and line fuse holder Refer to Paragraph 3 3 SERIAL I O DTE 9 pin D sub plug wired in DTE configuration for use with RS 232C serial computer interface Refer to Paragraph 6 2 and see Figure 8 6 PROBE INPUT 15 pin D sub socket for probes or Hall generator cables For best results secure the connector to the rea...

Страница 29: ... safety feature of the Model 475 If a fuse ever fails it is important to replace it with the value and type indicated on the rear panel for the line voltage setting The letter T on the fuse rating indicates that the instrument requires a time delay or slow blow fuse Fuse values should be verified any time line voltage configuration is changed Instructions for changing and verifying a line fuse are...

Страница 30: ...e a number of handling and accuracy requirements that must be observed 3 5 1 Probe Handling Although every attempt has been made to make the probes as sturdy as possible they are still fragile This is especially true for the exposed sensor tip of some transverse probes Care should be taken during measurements that no pressure is placed on the tip of the probe The probe should only be held in place...

Страница 31: ...Figure 3 4 NOTE For best results the instrument and probe should warm up for at least 5 minutes before zeroing the probe and at least 30 minutes for rated accuracy The probe and the zero gauss chamber should be at the same temperature If the exact direction of the magnetic field is unknown the proper magnitude is determined by turning on Max Hold and slowly adjusting the probe As the probe turns a...

Страница 32: ...ion Probe readings are dependent on the angle of the sensor Hall sensor in relation to the magnetic field Maximum output occurs when the flux vector is perpendicular to the plane of the sensor This is the condition that exists during factory calibration The greater the deviation from orthogonality from right angles in either of three axes the larger the error of the reading For example a 5 varianc...

Страница 33: ...g Output 2 The second voltage output provides a voltage proportional to measured field with the benefits of some signal processing The output is produced by the DSP through a fast D A converter The output signal is updated at 40 kHz giving good response for low to mid frequency fields Signal quality degrades at high frequency because of the sampling rate Probe offset correction and correction for ...

Страница 34: ...abinet using the optional Lake Shore Model RM Rack Mount Kit or the Model RM2 Dual Rack Mount Shelf The Rack Mount Kit contains mounting ears panel handles and screws that adapt the front panel to fit into a 3 5 inch tall full rack space Refer to Figure 3 7 and Figure 3 8 for installation details Figure 3 7 Model RM Rack Mount Kit P N 4022 ...

Страница 35: ...Lake Shore Model 475 Gaussmeter User s Manual Installation 3 9 Figure 3 8 Model RM2 Dual Rack Mount Shelf P N 4026 ...

Страница 36: ...Lake Shore Model 475 Gaussmeter User s Manual 3 10 Installation This Page Intentionally Left Blank ...

Страница 37: ...the power cord and turn on the instrument as described in Paragraph 3 3 4 Lak e Shor e 475 DSP Gaus s met er When the Model 475 is turned on the display reads Lake Shore for a few seconds and the alarm beeper sounds briefly to indicate the instrument is initializing Most instrument setup parameter values are retained when power is off with only a few exceptions When the instrument is powered on fo...

Страница 38: ...sing the various functions on the keypad Figure 4 2 Front Panel Display Definition 4 2 1 Display Units G m G G kG Field in Gauss T m T T Field in Tesla Oe m Oe Oe kOe Field in Oersted A m kA m M A m Field in Amp meter m Resistance in Ohms M X M N Maximum and Minimum from Max Hold PK PK Positive and Negative Peak readings DC RM S DC or RMS mode readings Hz kHz Frequency of RMS fields in Hz m K K Pr...

Страница 39: ... Chapter 6 Alarm Turns Alarm feature ON and OFF and setup alarm parameters Relay Setup Relay feature Units Configure units of measurement for Field and Temperature if available Select Range Manually selects field measurement range Probe Setup and view Probe parameters Extension cable programming 0 9 Numeric data entry within a setting sequence s Up Increments a parameter selection or value in a nu...

Страница 40: ...nce to next parameter Pressing Escape once will clear the new value and restart the setting sequence Pressing Escape again will return to the normal display Data entry screens always include the message Enter for followed by the parameter being set Related setting selection and data entry sequences are often chained together under a single key To skip over a parameter without changing its value pr...

Страница 41: ...4 5 UNITS To configure the field measurement units press Units The units setup screen appears as a prompt for the field measurement units Sel ect W i t h Uni t s Gaus s Use the s or t key to select the field units Gauss Tesla Oersted or Amp meter Press Enter to accept the new selection and return to the normal display Press Escape to cancel the new selection and return to the normal display To con...

Страница 42: ...00 kG 350 000 mT 3 50000 kOe 280 000 kA m 350 000 G 35 0000 mT 350 000 Oe 28 0000 kA m 35 0000 G 3 50000 mT 35 0000 Oe 2 80000 kA m High Sensitivity Probe HSE Gauss Tesla Oersted Amp meter Range and Resolution Range and Resolution Range and Resolution Range and Resolution 35 0000 kG 3 50000 T 35 0000 kOe 2 80000 MA m 3 50000 kG 350 000 mT 3 50000 kOe 280 000 kA m 350 000 G 35 0000 mT 350 000 Oe 28...

Страница 43: ...Maximum Reading Rate 3 3 100 Hz 100 1000 readings second 4 4 10 Hz 30 readings second 5 5 1 Hz 10 readings second Limited Feature set Interface dependent To configure the resolution press and hold the DC key for approximately 4 seconds The following screen appears as a prompt for DC resolution setting Sel ect W i t h Res ol ut i on 3 Di gi t s Use the s or t key to select from 3 4 or 5 digits Pres...

Страница 44: ...ocess the measured offset is larger than expected the Model 475 will put up the following message alerting to the user that there may be a problem with the probe Pr obe Of f set Lar ger Than Ex pec t ed The Model 475 will continue to operate with the offset correction but it will be up to the individual to investigate the nature of the offset 4 6 4 DC Operation Max Hold The Max Hold function captu...

Страница 45: ...eset Example If the present maximum reading is 30 kG and the instrument measures 10 kG the 10 kG becomes the new maximum reading If the minimum reading is 3 0 kG and the instrument measures 15 kG the 15 kG becomes the new minimum reading 0 kG 3 kG 10 kG 30 kG 15 kG 30 kG New Max Example of operation Algebraic Original Max New Min Original Min To configure the Max Hold measurement mode press and ho...

Страница 46: ...sent field reading 4 6 6 DC Operation Relative The relative function lets the user see small variations in larger fields When the relative function is on the relative readings will appear on the top line of the display including the small delta sign s signifying the relative display The displayed reading is equal to the present field value minus the relative setpoint The relative setpoint can be c...

Страница 47: ...er to accept the new selection and return to the normal display Press Escape to restart the setting sequence and enter a new value Press Escape again to cancel the sequence and return to the normal display NOTE The Relative Setpoint entry screen also appears under the press and hold feature of the Relative key if relative is configured for a user defined setpoint 4 6 7 DC Operation Analog Output 1...

Страница 48: ...ong with the display resolution Measurement resolution noise floor varies depending on probe and application but the Model 475 can typically measure signals as small as 0 1 of full scale range High Stability Probe HST Gauss Tesla Oersted Amp meter Range and Resolution Range and Resolution Range and Resolution Range and Resolution 350 00 kG 35 000 T 350 00 kOe 28 000 MA m 35 000 kG 3 5000 T 35 000 ...

Страница 49: ... to the normal display Press Escape to cancel the new selection and return to the normal display NOTE Autorange should not be used when measuring a small RMS field in the presence of a larger DC background 4 7 2 RMS Operation Filter Selection The Model 475 offers unique AC filtering capabilities to improve the overall RMS measurement performance The instrument may be configured to use a DC current...

Страница 50: ...ribed in the following table The start and stop frequencies are labeled in Figure 4 3 Filter Center Setting fc Hz Start Hz Stop Hz 100 70 130 200 140 260 400 280 520 800 560 1040 1600 1100 2100 3200 2200 4200 6400 4400 8400 None If Filter Band Wide is selected the next screen appears as a prompt for selecting the center frequency of the bandpass filter Sel ect W i t h Fi l t Cent er 100 Hz Use the...

Страница 51: ...uency of the bandpass filter Sel ect W i t h Fi l t Cent er 50 Hz Use the s or t key to select from 50Hz 60Hz 100Hz 120Hz 200Hz 400Hz or 800Hz Press Enter to accept the new selection and return to the normal display Press Escape to cancel the new selection and return to the normal display 4 7 2 3 Lowpass Filters The AC excitation is also used in the Lowpass filter configuration This allows the Mod...

Страница 52: ...rn to the normal display Most RMS measurements reject the DC component of the measured field This is the default configuration of the Model 475 If an application requires the inclusion of the DC it can be turned on The next screen appears as a prompt for rejecting the DC component Sel ect W i t h Rej ec t DC Yes Use the s or t key to select from Yes or No Press Enter to accept the new selection re...

Страница 53: ... reading update rate for each of the filter settings The display will update at 5 readings per second independent of the filter setting except for the lowpass filters which update once every 2 seconds Filter Type Filter Frequency Reading Rate Wide Band None 312 5 readings second Wide Band 6400 Hz 312 5 readings second Wide Band 3200 Hz 156 3 readings second Wide Band 1600 Hz 78 1 readings second W...

Страница 54: ... Use the s or t key to select Max Min or Both Press Enter to accept the new selection and return to the normal display Press Escape to cancel the new selection and return to the normal display 4 7 6 RMS Operation Reset If the Max Hold function is on and the Reset key is pressed the maximum and minimum readings are cleared and reset with the present field reading 4 7 7 RMS Operation Relative The re...

Страница 55: ...ss Enter to accept the new selection and return to the normal display Press Escape to restart the setting sequence and enter a new value Press Escape again to cancel the sequence and return to the normal display 4 7 8 RMS Operation Analog Output 1 and 2 If the instrument is configured in Wide Band RMS measurement mode Analog Output 1 is a real time analog signal proportional to the AC magnetic fie...

Страница 56: ...0 kG 350 00 mT 3 5000 kOe 280 00 kA m 350 00 G 35 000 mT 350 00 Oe 28 000 kA m 35 000 G 3 5000 mT 35 000 Oe 2 8000 kA m High Sensitivity Probe HSE Gauss Tesla Oersted Amp meter Range and Resolution Range and Resolution Range and Resolution Range and Resolution 35 000 kG 3 5000 T 35 000 kOe 2 8000 MA m 3 5000 kG 350 00 mT 3 5000 kOe 280 00 kA m 350 00 G 35 000 mT 350 00 Oe 28 000 kA m 35 000 G 3 50...

Страница 57: ...ositive peak reading PK is displayed on the top line when in Peak measurement mode Sometimes it may be beneficial to display the negative peak reading PK on the top line instead of the maximum The user may also display both peak readings with the positive reading on the top line and the negative reading on the bottom line Displaying both will override the two line display configuration when Peak i...

Страница 58: ...ure the field reading to use as the setpoint If a User Defined setpoint is selected the following screen appears as a prompt for entering the setpoint after the Relative On display disappears Ent er f or Rel at i ve Set p 35 0000 G Use the data entry keys to enter the high setpoint between 350 kG or equivalent depending on selected field units Enter the numeric value first Press Enter to accept th...

Страница 59: ...f f Use the s or t key to select Off or On Press Enter to accept the new selection and continue to the next setting screen Press Escape to cancel the new selection and return to the normal display The next alarm setup screen appears as a prompt for the low alarm setpoint value Ent er f or Al ar m Low 0 50000 k G Use the data entry keys to enter the low setpoint between 350 kG or equivalent dependi...

Страница 60: ...tpoint or below the low alarm setpoint This operation is achieved by setting the inside outside parameter to outside It is called outside because the alarm is active when the reading is outside the range of the two setpoints During magnet testing or sorting it is often desirable to have the alarm active when the field reading is inside or between the two setpoints This operation is achieved by set...

Страница 61: ...Operation 4 25 The Model 475 has an audible alarm annunciator or beeper The beeper will sound when the instrument is in an active alarm state If the sound of the beeper is not appropriate for your application it can be turned on or off by the user ...

Страница 62: ...following screen appears as a prompt for configuring the sort message Sel ec t W i t h Al ar m Sor t Of f Use the s or t key to select from Off or On Press Enter to accept the new selection and return to the normal display Press Escape to cancel the new selection and return to the normal display 4 11 RELAYS The Model 475 has two mechanical relays designated Relay 1 and Relay 2 The relays are most ...

Страница 63: ...lts will equal full scale for the selected range The DC voltage of Analog Output 3 can be configured so that 10 volts maximum will equal full scale for the selected range The high and low limits can be configured so that lower voltages will equal full scale for the selected range 4 12 1 Analog Output 3 Mode Setting Analog Output 3 may be configured in five different modes of operation The followin...

Страница 64: ...o the normal display The next analog setup screen appears as a prompt for the high setpoint value This value represents the reading at which the Analog Output 3 will be 10 volts Ent er f or Anal og Out Hi gh 3 50000 k G Use the data entry keys to enter the high setpoint between 350 kG or equivalent depending on selected units Enter the numeric value first Press Enter to accept the new value and ad...

Страница 65: ...trol parameters Paragraph 5 2 4 12 2 Analog Output 3 Polarity The Analog Output 3 can be configured to operate either in a unipolar fashion output from 0 volts to 10 volts or in a bipolar fashion output from 10 volts to 10 volts To configure the Analog Output 3 polarity press and hold the Analog key for approximately 4 seconds The following screen appears as a prompt for configuring the polarity S...

Страница 66: ...ld the Enter key for 5 seconds The following screen appears as a prompt for the 3 digit lock code Ent er Code To Loc k Key pad Use the data entry keys to enter the 3 digit lock code default 123 The instrument returns to the normal display with the keypad locked To unlock the instrument keypad press and hold the Enter key for 5 seconds The following screen appears as a prompt for the 3 digit lock c...

Страница 67: ...tput Analog Output 3 Mode Off Analog Output 3 Polarity Bipolar Analog Output 3 Limit 10V Analog Output 3 Manual Out 0 Computer Interface Baud 9600 IEEE Address 12 IEEE Terminators CR LF Trigger Output Off Datalog Rate 1 rdg s Display Bottom Line Temp Freq Brightness 75 Field Units Gauss Temperature Units C Field Control Control Mode Off Setpoint 0 G Setpoint Ramp Rate 3 5 kG min Control Slope Limi...

Страница 68: ...Lake Shore Model 475 Gaussmeter User s Manual 4 32 Operation This Page Intentionally Left Blank ...

Страница 69: ...he effects of the zero probe function press and hold the Zero Probe key for approximately 4 seconds The screen appears as a prompt for clearing the zero probe function Sel ect W i t h Cl ear Zer os No Use the s or t key to select Yes or No Press Enter to accept the new selection and return to the normal display Press Escape to cancel the selection and return to the normal display 5 1 2 Probe Seria...

Страница 70: ...the probe when longer cables are needed Keeping probes and their extensions from getting mixed up can become a problem when more than one probe is in use The Model 475 alleviates some of the difficulty by allowing users to match probes to extensions in the field Stored information can be viewed on the front panel and read over computer interface to ensure proper mating NOTE Calibrated probe and ex...

Страница 71: ...he Hall sensor linearity If the HMCBL cable is not loaded with sensitivity information or a 0 0 sensitivity is mistakenly entered the Model 475 reverts to resistance measurement otherwise the instrument will use the previously loaded sensitivity 5 2 1 User Programmable Cable If the Model 475 detects the presence of a HMCBL cable with no sensitivity information a new blank cable the instrument will...

Страница 72: ...mA the proper sensitivity to enter is approximately 0 1 that of the 100 mA value Ent er f or M CBL Sens 1 00000 mV k G Use the data entry keys to enter the nominal sensitivity value from one of the following ranges between 0 550 and 1 100 mV kG between 5 500 and 11 000 mV kG and between 550 and 1100 mV kG when using a control current of 100 mA Press Enter to accept the new value and return to the ...

Страница 73: ... Control key The first control setup screen appears as a prompt for turning control On or Off If control is already On this screen will be skipped and the setpoint change screen will appear Sel ect W i t h Cont r ol Of f Use the s or t key to select from Off or On Press Enter to accept the new selection and continue to the next setting screen Press Escape to cancel the selection and return to the ...

Страница 74: ...ress Escape again to cancel the sequence and return to the normal display 5 3 4 Control Setpoint Ramp Rate The Model 475 can also be configured to ramp the control setpoint from the present field reading to a new value The ramp may allow a smooth linear transition in field rather than the typical step response associated with Closed Loop PI control The ramp rate is described as units per minute wh...

Страница 75: ...st often P will decrease and I will increase In most cases A DC resolution setting of 5 results in a very slow field control independent of the PI parameters and makes field control difficult 5 4 DATALOG Memory within the instrument provides storage for up to 1024 field readings in a data buffer The buffer can be filled at high speed up to 1000 readings per second After the data has been filled th...

Страница 76: ...nnector which is described in Paragraph 3 6 The timing of the hardware trigger input and output are described in Figures 5 1 and 5 2 The hardware trigger input is an edge sensitive active low signal To ensure that the trigger is detected by the Model 475 it is recommended that the signal be held high for a minimum of 25 microseconds and then held low for another 25 microseconds before going high a...

Страница 77: ...he devices on the bus which function to perform The Model 475 performs the functions of TALKER and LISTENER but cannot be a BUS CONTROLLER The BUS CONTROLLER is the digital computer which tells the Model 475 which functions to perform Below are Model 475 IEEE 488 interface capabilities SH1 Source handshake capability RL1 Complete remote local capability DC1 Full device clear capability DT1 Complet...

Страница 78: ... new selection and return to the normal display 6 1 2 Remote Local Operation Normal operations from the keypad are referred to as Local operations The Model 475 can also be configured for Remote operations via the IEEE 488 interface or the Local key The Local key will toggle between Remote and Local operations During Remote operations the Remote LED annunciator will light and operations from the k...

Страница 79: ... are addressed commands The Model 475 supports a variety of device specific commands to program instruments remotely from a digital computer and to transfer measurements to the computer Most device specific commands perform functions also performed from the front panel Model 475 device specific commands are detailed in Paragraph 6 3 and summarized in Table 6 9 6 1 3 4 Message Strings A message str...

Страница 80: ...It is not recommended to make configuration changes during the high speed transfer Refer to Paragraph 6 3 1 for command description Figure 6 1 describes the format of the data Figure 6 1 IEEE 754 Single Precision Data Format s sign bit with 0 positive and 1 negative e exponent bits f fraction bits The header is sent at the start of each transmission and may be discarded by the user The transmissio...

Страница 81: ...ster will set the summary bit for the register set in the Status Byte The user may write to or read from an enable register Each event register bit is logically ANDed to the corresponding enable bit of the enable register When an enable register bit is set by the user and the corresponding bit is set in the event register the output summary of the register will be set which in turn sets the summar...

Страница 82: ...Lake Shore Model 475 Gaussmeter User s Manual 6 6 Remote Operation Figure 6 2 Model 475 Status System ...

Страница 83: ... desired binary weighted sum of all bits in the register refer to Table 6 1 The actual commands are described later in this section 6 1 4 1 7 Clearing Registers The methods to clear each register are detailed in Table 6 2 Table 6 2 Register Clear Methods Register Method Example Condition Registers None registers are not latched Event Registers Standard Event Status Register Operation Event Registe...

Страница 84: ... This bit indicated a query error It occurs rarely and involves loss of data because the output queue is full Operation Complete OPC Bit 0 When OPC is sent this bit will be set when the instrument has completed all pending operations The operation of this bit is not related to the OPC command which is a separate interface feature Refer to Paragraph 6 1 4 3 6 for more information Figure 6 3 Standar...

Страница 85: ...as occurred Request Service RQS Master Summary Status MSS Bit 6 This bit is set when a summary bit and the summary bits corresponding enable bit in the Service Request Enable Register are set Once set the user may read and clear the bit in two different ways which is why it is referred to as both the RQS and the MSS bit When this bit goes from low to high the Service Request hardware line on the b...

Страница 86: ...y bit or MAV bit is enabled by the Service Request Enable Register and goes from 0 to 1 bit 6 RQS MSS of the status byte will be set This will send a service request SRQ interrupt message to the bus controller The user program may then direct the bus controller to serial Poll the instruments on the bus to identify which one requested service the one with bit 6 set in its status byte Serial polling...

Страница 87: ...t the bus controller to look for the SRQ leaving the bus available for other use The MAV bit will be clear whenever the output buffer is empty 6 1 4 3 6 Using Operation Complete OPC and Operation Complete Query OPC The Operation Complete OPC and Operation Complete Query OPC are both used to indicate when pending device operations complete However the commands operate with two distinct methods The ...

Страница 88: ... 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 support any 16 bit Windows GPIB applications being used 3 Locate the following files and make note of their location The...

Страница 89: ...Lake Shore Model 475 Gaussmeter User s Manual Remote Operation 6 13 Figure 6 6 GPIB0 Setting Configuration Figure 6 7 DEV 12 Device Template Configuration ...

Страница 90: ...erface 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 Comm...

Страница 91: ...indow 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 5 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...

Страница 92: ...ue 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 Handle ...

Страница 93: ...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 1 6 Troubleshooting New Installation 1 Chec...

Страница 94: ...rument to computers with either 9 or 25 pin connectors Paragraph 8 11 1 gives the most common pin assignments for 9 and 25 pin connectors Please note that not all pins or functions are supported by the Model 475 The instrument serial connector is the plug half of a mating pair and must be matched with a socket on the cable If a cable has the correct wiring configuration but also has a plug end a g...

Страница 95: ...error detection One parity bit configured for odd parity is included in each character ASCII letter and number characters are used most often as character data Punctuation characters are used as delimiters to separate different commands or pieces of data Two special ASCII characters carriage return CR 0DH and line feed LF 0AH are used to indicate the end of a message string Table 6 6 Serial Interf...

Страница 96: ... a given time or guarantee timing between messages All of this is the responsibility of the user program When issuing commands only the user program should Properly format and transmit the command including terminators as one string Guarantee that no other communication is started for 50 ms after the last character is transmitted Not initiate communication more than 20 times per second When issuin...

Страница 97: ... size 4 On the Project Menu click Components to bring up a list of additional controls available in VB6 5 Scroll through the controls and select Microsoft Comm Control 6 0 Select OK In the toolbar at the left of the screen the Comm Control will have appeared as a telephone icon 6 Select the Comm control and add it to the form 7 Add controls to form a Add three Label controls to the form b Add two ...

Страница 98: ...blic gSend as Boolean b Double Click on cmdSend Add code segment under Private Sub cmdSend_Click as shown in Table 6 8 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 8 d Double Click on the Tim...

Страница 99: ...op 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 While Ze...

Страница 100: ...program If you enter 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 ...

Страница 101: ...a String of alpha numeric characters nnn nnnE nn Number represented in scientific notation format term Terminator characters Indicated a parameter field many are command specific state Parameter field with only On Off states NOTE Any number being represented in scientific notation may also be entered as a string of number characters The following example shows two different ways of sending the sam...

Страница 102: ... Filter Parameter Query 6 33 IEEE IEEE 488 Interface Parameter Cmd 6 33 IEEE IEEE 488 Interface Parameter Query 6 34 KEYST Keypad Status Query 6 34 Command Function Page LOCK Front Panel Keyboard Lock Cmd 6 34 LOCK Front Panel Keyboard Lock Query 6 34 MXHOLD Max Hold Cmd 6 34 MXHOLD Max Hold Query 6 34 MXRST Max Hold Reset Cmd 6 34 MODE Remote Interface Mode Cmd 6 35 MODE Remote Interface Mode Que...

Страница 103: ...t weighting term Format nnn Refer to command for description ESR Standard Event Status Register Query Input ESR term Returned bit weighting Format nnn Remarks Bits in this register correspond to various system events and latch when the event occurs When an event bit is set subsequent events corresponding to that bit are ignored Set bits remain latched until the register is reset by this query or a...

Страница 104: ...e to generate a Service Request This command programs the enable register using a decimal value which corresponds to the binary weighted sum of all bits in the register Refer to Paragraph 6 1 4 3 SRE Service Request Enable Register Query Input SRE term Returned bit weighting term Format nnn Refer to command for description STB Status Byte Query Input STB term Returned bit weighting term Format nnn...

Страница 105: ...n n nnn nnnE nn nnn nnnE nn n n Refer to command for description ALARMST Alarm Status Query Input ALARMST term Returned state term Format n state 0 Off 1 On ANALOG Analog Output 3 Parameter Command Input ANALOG mode polarity low value high value manual value voltage limit term Format n n nnn nnnE nn nnn nnnE nn nnn nnnE nn nn mode Specifies data the analog out 3 monitors 0 off 1 default 2 user def...

Страница 106: ...n Example AUTO 1 term Turns on the autorange feature AUTO Auto Range Query Input AUTO term Returned off on term Format n Refer to command for description BAUD RS 232 Baud Rate Command Input BAUD bps term Format n bps 1 9600 Baud 2 19200 Baud 3 38400 Baud 4 57600 Baud BAUD RS 232 Baud Rate Query Input BAUD term Returned bps term Format n Refer to command for description BEEP Alarm Beeper Command In...

Страница 107: ...ts Setting to 0 will turn ramping off control slope limit Analog Output limit in Volts minute 0 01 to 1000 Example CPARAM 10 50 3000 75 term Field Control P is 10 I is 50 and when the CSETP command is issued the field setpoint will ramp at a rate of 3000 Gauss minute The Analog Output will be limited to a 75 Volts minute change CPARAM Field Control Parameter Query Input CPARAM term Returned P valu...

Страница 108: ...475 is in RMS mode DISPLAY Display Configuration Query Input DISPLAY term Returned item term Format n Refer to command for description DLOG Datalog Stop Start Command Input DLOG stop start term Format n stop start Starts and stops the datalog function 0 Stop 1 Start Remarks Use the DLOGSET command to set the datalog rate The DLOGNUM command can be used to determine how many datalog points have bee...

Страница 109: ... narrow band filter 1 50 Hz 2 60 Hz 3 100 Hz 4 120 Hz 5 200 Hz 6 400 Hz 7 800 Hz rmslp Selects corner frequency of the RMS low pass filter 1 20 Hz 2 60 Hz 3 140 Hz Example FILTER 3 5 2 term Configures the RMS wide band filter center frequency to 400 Hz the RMS narrow band center frequency to 200 Hz and the RMS low pass corner frequency to 60 Hz FILTER Filter Parameter Query Input FILTER term Retur...

Страница 110: ...ut LOCK term Returned state code term Format n nnn Refer to command for description MXHOLD Max Hold Command Input MXHOLD off on mode display term Format n n n off on Specifies Max Hold on or off 0 off and 1 on mode Specifies checking magnitude absolute value used or algebraically includes sign 1 Magnitude check 2 Algebraic check display Specifies Display configuration when Max Hold is on 1 Display...

Страница 111: ... bit in the Operational Status Register This determines which status bits can set the corresponding summary bit in the Status Byte Register To enable a status bit send the command OPSTE with the sum of the bit weighting for each desired bit Refer to Paragraph 6 1 4 2 2 for a list of operational status bits OPSTE Operational Status Enable Query Input OPSTE term Returned bit weighting term Format nn...

Страница 112: ...M term Returned type term Format xxxxxxxxxx Remarks Returns the probe serial number PRBTCOMP Probe Temperature Compensation Command Input PRBTCOMP off on term Format n off on Specifies Probe Temperature compensation off or on Valid entries 0 off 1 on Example PRBTCOMP 1 term Field Measurement is compensated for present probe temperature PRBTCOMP Probe Temperature Compensation Query Input PRBTCOMP t...

Страница 113: ... operating resolution in number of digits 1 3 digits 2 4 digits 3 5 digits rms filter mode Filter band type for RMS measurement 1 wide band 2 narrow band 3 low pass peak mode Specifies peak measurement mode 1 periodic 2 pulse peak disp Specifies display of peak reading 1 positive 2 negative 3 both Remarks Reference the FILTER command for information on configuring the filter parameters for each me...

Страница 114: ...L Relative Reading Query Input RDGREL term Returned relative reading term Format nnn nnnE nn Remarks Returns the relative field reading RDGTEMP Probe Temperature Reading Query Input RDGTEMP term Returned temperature term Format nnn nnnE nn Remarks Returns the probe temperature reading in a format based on the present temperature units REL Relative Mode Command Input REL off on setpoint source term...

Страница 115: ...er term Format n relay number Specifies which relay to query 1 Relay 1 2 Relay 2 Returned status term Format n 0 Off 1 On RELSP Relative Setpoint Command Input RELSP setpoint term Format nnn nnnE nn setpoint Specifies the setpoint to use in the relative calculation 350 kG Example RELSP 1200 term Configure the relative setpoint as 1200 Gauss if units in Gauss The relative reading will use this valu...

Страница 116: ... high sensitivity 50 user programmable cable high sensitivity probe 51 user programmable cable high stability probe 52 user programmable cable ultra high sensitivity probe UNIT Field Units Command Input UNIT units term Format n units 1 Gauss 2 Tesla 3 Oersted 4 Amp meter Example UNIT 2 term Configures the Model 475 to report readings in Tesla UNIT Field Units Query Input UNIT term Returned units t...

Страница 117: ...on of Accessories G 106 253 25 pin D Sub Plug Used for I O mating connector G 106 264 25 pin D Sub Shell Used for I O mating connector 4005 IEEE 488 Cable Kit One meter 3 feet long IEEE 488 GPIB computer interface cable assembly Includes extender required to use both IEEE cable and Auxiliary I O connector simultaneously 4060 Standard Zero Gauss Chamber For standard probe offset nulling Size 32 32 ...

Страница 118: ...rformance is slightly degraded with minimum sensitivity of 50 mG 5 µT High stability probes are also inherently more temperature stable than other probes and should be used when large temperature excursions are expected The same probe geometries are available for both HST and HSE probes HST probes are not to be used at frequencies above 800 Hz Ultra High Sensitivity UHS Low magnitude large volume ...

Страница 119: ...would be easier if all fields were large and uniform but that is seldom the case because most fields are limited in volume and contain gradients changes in magnitude Hall effect probes measure an average magnitude over their active area making it necessary to understand the relationship between active area and field gradients Severe field gradients are always experienced as the active sense elemen...

Страница 120: ...unction Refer to Paragraph 4 6 6 Probe temperature can also affect readings Refer to the two separate temperature coefficients listed on the specification sheet The High Stability HST probes exhibit a low temperature coefficient of gain due to the inherent thermal stability of the materials used in their construction Probe readings are dependent on the angle of the sensor Hall sensor in relation t...

Страница 121: ...0 feet HMPEC 25 HMPEC 25 U Probe Extension Cable 8 meters 25 feet HMPEC 50 HMPEC 50 U Probe Extension Cable 15 meters 50 feet HMPEC 100 HMPEC 100 U Probe Extension Cable 30 meters 100 feet HMCBL XX Hall Generator Cable Assembly The HMCBL Cable Assembly connects a discrete Hall generator to the Model 475 Gaussmeter Refer to Paragraph 7 5 Because of the many calibration intricacies the user is respo...

Страница 122: ...ce 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 Magnet 0 062 inch gap 500 G 1 MRT 062 1K Transverse Reference Magnet 0 062 inch gap 1 kG 0 5 MRT 062 2K Transverse Referenc...

Страница 123: ...on The Model HGCA 3020 and HGCT 3020 Hall generators have 34 AWG stranded copper lead wire with Teflon insulation and have the following color coded lead configuration 7 5 3 Using a Hall Generator with the Model 475 Connecting a Hall generator to the Model 475 requires a Lake Shore Model HMCBL 6 or 20 Cable Assembly sold separately The cable has a 15 pin D sub connector on one end and four leads o...

Страница 124: ... Cable Accessory CAUTION The Hall Generator should be isolated from all line voltages or voltages referenced to earth ground If not damage to the Model 475 Gaussmeter is almost a certainty IMPORTANT Refer to our website for information about Hall generators manufactured by Lake Shore http www lakeshore com products Cryogenic Temperature Sensors Cryogenic Hall Generators and Probes Pages Overview a...

Страница 125: ...s can be used as low field reference magnets to complement our set of standard reference magnets defined in Paragraph 7 7 To achieve maximum field the power supply must be capable of 2 A output and a constant current mode is recommended MH 2 5 MH 6 MH 12 Inside Diameter 2 5 inches 6 inches 12 inches Field Accuracy 0 5 Field Strength 30 G 1 A 25 G 1 A 13 G 1 A Field Homogeneity 0 5 within a cylindr...

Страница 126: ...Lake Shore Model 475 Gaussmeter User s Manual 7 10 Probes and Accessories Helmholtz_6 bmp Figure 7 14 Model MH 6 Helmholtz Coil Helmholtz_12 bmp Figure 7 15 Model MH 12 Helmholtz Coil ...

Страница 127: ...es ranging from 100 G to 20 kG but the most widely used value is 1 kG Reference magnet 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 inc...

Страница 128: ... a magnetized chamber to zero a probe can lead to erroneous field readings It is a good practice to periodically degauss the chamber If no professional degausser is available a bulk tape degausser Verity VS250 Data Devices PF211 or equivalent may be used 4060_Chamber eps Figure 7 17 Model 4060 Zero Gauss Chamber 4065_Chamber eps Figure 7 18 Model 4065 Large Zero Gauss Chamber ...

Страница 129: ... Sales Instrument Service Fax 614 818 1600 614 818 1609 Sales Instrument Service When contacting Lake Shore please provide your name and complete contact information including e mail address if possible It is often helpful to include the instrument model number and serial number located on the rear panel of the instrument as well as the firmware revision information as described in Paragraph 4 14 ...

Страница 130: ... See Figure 8 2 2 Turn the line power switch OFF O 3 Remove the instrument power cord 4 With a small screwdriver release the drawer holding the line voltage selector and fuse 5 Slide out the removable plastic fuse holder from the drawer 6 Rotate the fuse holder until the proper voltage indicator shows through the window 7 Verify the proper fuse value 8 Re assemble the line input assembly in the re...

Страница 131: ...ot configured to support a feature Instrument Hardware Defective RAM Internal RAM is defective and must be replaced Invalid EEPROM EEPROM contents are corrupt and parameter values will be reset to default Reoccurrence may indicate defective EEPROM Calibration may be affected Input Not Responding Internal processor communication has failed Invalid Calibration Instrument has not been calibrated or c...

Страница 132: ...entification of Electrostatic Discharge Sensitive Components The following are various industry symbols used to label components as ESDS 8 7 2 Handling Electrostatic Discharge Sensitive Components Observe all precautions necessary to prevent damage to ESDS components before attempting installation Bring the device and everything that contacts it to ground potential by providing a conductive surfac...

Страница 133: ...ATION 1 Slide the top panel forward in the track provided on each side of the unit 2 Carefully replace the back bezel by sliding it straight into the unit 3 Use 5 64 hex key to install 4 screws attaching top panel to unit 4 Use 5 64 hex key to tighten 2 screws attaching rear bottom panel to unit 5 If required reattach 19 inch rack mounting brackets 6 Connect power cord to rear of unit and set powe...

Страница 134: ...Lake Shore Model 475 Gaussmeter User s Manual 8 6 Service PCB Layout bmp Figure 8 3 Location of Important Internal Components ...

Страница 135: ...ow the top of enclosure INSTALLATION procedure in Paragraph 8 8 8 10 CONNECTOR AND CABLE DEFINITIONS The AUXILIARY I O PROBE INPUT SERIAL I O DTE and IEEE 488 INTERFACE connectors are defined in Figures 8 4 thru 8 7 Auxiliary_IO bmp Pin Description Pin Description 1 2 3 4 5 6 7 8 9 10 11 12 13 Analog Out 1 Analog Out 2 Analog Out 3 No Connection Trigger In Trigger Out No Connection Relay 1 NO Rela...

Страница 136: ... bmp Model 475 Gaussmeter Typical Computers SERIAL I O DTE DB 25P DTE DE 9P DTE 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 6 Data Set Ready DSR in 7 GND 6 DSR in 7 Data Terminal Ready DTR out tied to 4 8 D...

Страница 137: ... 7 RTS out 7 DTR tied to 4 8 CTS in 8 NC 1 DCD in Model 475 to PC Serial Interface PC with DB 25P Model 475 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 475 to PC Interface using Null Modem Adapter Model 475 DE 9P Null Modem Adapter PC DE 9P ...

Страница 138: ...ame time Figure 8 7 shows the IEEE 488 Interface connector pin location and signal names as viewed from the Model 475 rear panel IEEE_Connector bmp 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 DIO 1 DIO 2 DIO 3 DIO 4 EOI DAV NRFD NDAC IFC SRQ ATN SHIELD DIO 5 DIO 6 DIO 7 DIO 8 REN GND 6 GND 7 GND 8 GND 9 GND 10 GND 11 GND Data Input Output Line 1 Data Input...

Страница 139: ...red by using the HP 3458 to measure the current source of the 475 and the voltage across the resistor This configuration is only valid for this range because the accuracy of the HP3458 is unacceptable for the remaining Model 475 ranges Therefore the remaining ranges are calibrated by using the previous calibrated range as shown in the following steps 8 11 2 1 Gaussmeter Calibration 100 mA Excitati...

Страница 140: ...r those two ranges are equivalent 36 Send the CALSAVE command to save the calibration constants into non volatile memory 8 11 2 2 Gaussmeter Calibration 10 mA Excitation Ranges This section describes the method of calibrating the 10 mA current source that may be used for future Hall sensors The five ranges of the 475 will need to be calibrated for each current setting The highest range is for each...

Страница 141: ... short across the Gaussmeter input of the Model 475 using a proper 4 lead connection 5 Configure the 475 for 1 mA excitation current HALLCS 3 6 Configure the 475 for DC 5 digits RDGMODE 1 3 1 1 1 on the 350 Ω range RANGE 5 7 Zero the probe using the Zero Probe key or the ZPROBE command 8 Connect the 332 Ω resistor across the Gaussmeter input of the Model 475 using a proper 4 lead connection 9 Conf...

Страница 142: ...TEMP 1 1 200 kΩ 1 00 2 DVM Measure 0 05 14 Configure the 475 for temperature autoranging CALTEMP 0 3 15 Send the CALSAVE command to save the calibration constants into non volatile memory 8 11 4 Analog Output 2 and 3 Calibration This section will perform the actual calibration of Analog Output 2 and 3 This involves reading the positive and negative full scale output voltages of each output calcula...

Страница 143: ...he DVM Record as VMAX 7 Calculate the Gain Correction Factor GCF 20 VMAX VMIN Note Gain is calculated over the full span of the output Test this factor to be 1 0 1 Record this value 8 Send the Gain Correction Factor GCF to the Model 475 CALG 4 3 GCF 9 Configure Analog Output 3 to manual mode 0 ANALOG 3 2 0 0 0 10 10 Read the voltage using the DVM Record as VZERO 11 Calculate the Offset Correction ...

Страница 144: ...are indicated by not used No value should be sent to these locations CALG Gain Calibration Constant Query Input CALG type range term Format n n type 1 5 range 1 5 Returned value term Format nnnnnnn Refer to command for description CALSAVE Calibration Save Command Input CALSAVE term Remarks Saves all CALZ and CALG calibration constants in non volatile memory CALTEMP Temperature Measurement Setup Co...

Страница 145: ...d value Zero offset calibration constant value Remarks The range variable is ignored but needs to be sent for types that do not need to specify a range types 2 3 and 4 A range value of 1 should be sent for those types The hall current sources do not have a calibrated zero The offset is corrected using the Zero Probe function CALZ Zero Offset Calibration Constant Query Input CALZ type range term Fo...

Страница 146: ...m Returned code term Format nn Refer to command for description 00 no key pressed since last query 01 02 Up 03 Escape 04 Max Hold 05 Peak 06 07 Down 08 Enter 09 Relative 10 Reset 11 1 12 2 13 3 14 4 15 5 16 6 17 7 18 8 19 9 20 0 21 DC 22 RMS 99 multiple keys pressed simultaneously MOUT Analog Output 2 Setup Command Input MOUT mode setting term Format n nnnnnnn mode Specifies the operating mode Ana...

Страница 147: ...olume energy density energy productk W erg cm3 10 1 J m3 Demagnetization factor D N dimensionless 1 4π dimensionless NOTES a Gaussian units and cgs emu are the same for magnetic properties The defining relation is B H 4πM 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 Wh...

Страница 148: ...357 10 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 γp 2 6752 108 s 1 T 1 Diamagnetic Shielding Factor Spherical H2O Sample 1 σ H2O 1 0000 Mola...

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