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Lakeshore Learning Materials 642 User's Manual

1. From Sheet 20f2 Computer Interface Operation 5 5 Lake Shore Model 642 Electromagnet Power Supply User s Manual Error Status Condition Register ERST Error Status Event Register ERSTR Hardware Errors TF Temperature Fault OOV Output Over Voltage OOC Output Over Current DAC DAC Processor Not Responding OCF Output Control Failure Error Status Enable Register EAN ERSTE ERSTE Error Status Condition Register ERST Error Status Event Register ERSTR Operational Errors REF Remote Enable Fault PFF Power Supply Flow Switch Fault MFF Magnet Flow Switch Fault HLV High Line Voltage LLV Low Line Voltage TH Temperature High EPE External Current Program Error CAL Calibration Error Error Status Enable Register ERSTE ERSTE Bit Name e a lie lis ie JU Z Not De di pooole Bit Name 5 4 steatito EE Bb 1 owe fo foo To Sheet 1 of 2 o Lem Name Bit Name ARES EE A AO 7 eo s 3 2 3 0 Bit er ee ver ror anv fare ox na To Sheet 1 of 2 AND 1 E E EA E E Bit Name Figure 5 1 Model 642 Status System Sheet 2 of 2 5 6 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 4 1 6 Any register in the status system may be
2. Relative Humidity F 100 95 90 amp 8 7 70 560 5 50 4 40 HB BD BD B 15 10 90 88 87 85 83 81 79 76 74 71 68 65 52 59 54 49 43 36 32 85 83 81 80 78 76 74 72 69 67 64 61 58 54 50 45 38 32 80 78 77 75 73 71 69 67 65 62 59 56 53 50 45 40 35 32 75 73 72 70 68 66 64 62 60 58 55 52 49 45 41 36 32 70 68 67 65 63 61 59 57 55 53 50 47 44 40 37 32 S 65 63 62 60 59 57 55 53 50 48 45 42 40 36 32 S E siaj3iai388aSs 60 58 57 55 53 52 50 48 45 43 41 38 35 32 Example Determine the actual air temperature and relative humidity Find the closest air temperature in the left hand column and the closest relative humidity across the top If the air temperature is 24 C 75 F and the relative humidity is 35 the intersection of the two shows a dew point of 7 C 45 F Therefore for the given conditions the cooling water must remain above 7 C 45 F to prevent condensation 2 8 Magnet System Design Lake Shore Model 642 Electromagnet Power Supply User s Manual CHAPTER 3 INSTALLATION 3 0 GENERAL This chapter provides general installation instructions for the
3. Use the data entry keys to enter an output current setting value between 70 0000 and 70 0000 Press Enter to accept the new value Press Escape to restart the setting sequence and enter a different value Press Escape again to leave the setting sequence NOTE The output current setting value can be set as high as 70 1000 A This can be used to compensate for variances in calibration The output current is guaranteed to reach a minimum of 70 A into a 0 5 ohm load but may not be able to reach 70 1 A in all circumstances The output current setting is not allowed to change if the instrument is setup so that the output current is programmed solely by an external voltage Refer to Paragraph 4 15 to setup the external current program mode 4 7 CURRENT RAMP RATE The output current of the Model 642 will always ramp from one current setting to another There is no way to turn off the current ramping function but if a very fast ramp rate is desired a ramp rate as high as 99 999 A s can be entered To change the current ramp rate press the Ramp Rate key The ramp rate value on the normal display will be highlighted to prompt for the new ramp rate value Use the data entry keys to enter the ramp rate value between 0 0001 and 99 999 A s Press Enter to accept the new value Press Escape to restart the setting sequence and enter a different value Press Escape again to leave the setting sequence 4 8 RAMP SEGMENTS
4. User s Manual Model 642 Electromagnet Power Supply K a D 2 z 5 EINEN 69 9996 34 055 ei Z g e el Ei D e BLakeShore z re b El akeShore Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville Ohio 43082 8888 USA E mail Addresses sales lakeshore com service lakeshore com Visit Our Website At www lakeshore com Fax 614 891 1392 Telephone 614 891 2243 Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics Inc No government or other contractual 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 notice Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing performance or use of this material Revision 1 3 P N 119 042 9 January 2008 Lake Shore Model 642 Electromagnet Power Supply User s Manual LIMITED WARRANTY STATEMENT WARRANTY PERIOD ONE 1 YEAR 1 Lake Shore warrants that this Lake Shore product the Product will be free from defects in materials and workmanship
5. 1x Lake Shore Model 642 Electromagnet Power Supply User s Manual LIST OF TABLES Table No Title Page 3 1 Rear Panel Connector Identification cecceecceeeeeeeeeeeeneeeeeeeeeneeeeeeeeaeeesaeeeaeeeseeeeaeeeeeeeeeseeeseeeenaeessaeeeeees 3 2 3 2 Voltage and Current Select rsin odin hipaa A eee ee eee 3 3 3 3 Current Capacity and Total Lead Lengths 0 0 0 ecceeeceeeeneeeeeeeeeeeeeeeeeseaeeeeaeeseaeeseaeeseaeeseaeeseaeeseaeeseeeeeieetaes 3 9 4 1 Model 642 LED DeScriptiOns i cccsisceciesascenessdecapasaesesacuadscagdesaz saa Aaaa ROEA aae Paa ra Aarah Siae Pn OEA EE EETAS EAEE REA 4 2 4 2 Model 642 Key Descriptions ccececcceceseeeeeteeeeeeeteceeeeesteeecesgeeeenaeseesenansesesueseeseseesesesaeeesdeeeeeesensenesenees 4 3 4 3 Default Parameter Values sica iia de ii id EENS Keen 4 12 5 1 Binary Weighting of an 8 Bit Register AAA 5 7 5 2 Register Clear Methods iio E id linia 5 7 5 3 Programming Example to Generate an GO 5 13 5 4 IEEE 488 Interface Program Control Properties eccceesceeeeceeeeeeeeneeeeeeteaeeeeaeeseaeeenaeeseeeseaeeseeeseeeenaes 5 17 5 5 Visual Basic IEEE 488 Interface Program 0 c ceessceeeesneeeeeeneeeeeeeneeesenaeeeeseeeeeeeeaeeesesaeeeesenaeeeeseetetenaaes 5 18 5 6 Serial Interface Gpechficattons AA 5 22 5 7 Serial Interface Program Control Properties ccceecceeeeeeeeeeeceneeeeeeeceaeeeeaeeseaeeeaeeseaeesaeeseaeessaeesieeeeaeeees 5 25 5 8 Visual Basic Serial Interface Progr
6. STOP J CHASSIS EMERGENCY E STOP CHASSIS EMERGENCY E STOP CHASSIS E Uhl FAULT NO FAULT NO FAULT NO FAULT COM FAULT COM FAULT COM TO REMOTE ALARM CIRCUIT FAULTNC FAULT NC FAULT NC ge REMOTE _ REMOTE REMOTE ENABLE Go _ ENABLE ENABLE E NO SWITCHES EMERGENCY STOP ALARM CONTACTS amp REMOTE ENABLE Figure 3 9 Typical Auxiliary Connector Wiring Installation 3 7 Lake Shore Model 642 Electromagnet Power Supply User s Manual 3 6 POWER SUPPLY CONNECTOR The Power Supply connector provides terminals for an optional water flow switch and an optional cooling water control solenoid valve The flow switch must have a normally closed contact rated at 5 V at 10 mA contact closure is required to enable the Model 642 output If a switch is not used a jumper is required 24 VAC at 1 A is provided to operate a water control solenoid valve for the power supply cooling water This output is controlled by the power supply either automatically via software or manually through the Internal Water menu Water control is desirable to reduce water consumption when the water comes from a municipal facility Turning the water off when it is not required also reduces the probability of condensation within the power supply and connecting tubing If the cooling water comes from a facility chiller system condensation is not usually a problem and a control valve is not required Figure 3 10 shows
7. This method is somewhat lengthy but averages the differences between positive and negative excursions 7 11 3 7 Calibrate Voltage Reading Gain Send CALG 5 1 To set the output voltage reading gain constant to 1 Set the Model 642 output current to 65 A Wait 30 seconds Measure the Model 642 actual output voltage at the output terminals and record V measuredpos Get the Model 642 output voltage reading by front panel or interface and record V readingpos Set the Model 642 output current to 65 A Wait 30 seconds Measure the Model 642 actual output voltage at the output terminals and record V measuredneg O Ooa E cc GE Get the Model 642 output voltage reading by front panel or interface and record V readingneg he o Calculate gain constant per the following equation Voltage Reading Gain Constant V measuredpos V measuredneg V readingpos V readingneg 11 Verify the gain factor to be 1 0 02 12 Send CALG 5 gain constant 13 Verify the Model 642 output voltage reading to match the actual output voltage within 0 001 V 14 Set the Model 642 output current to 0 A 15 Send CALSAVE to write this calibration to non volatile memory 7 20 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 11 3 8 Calibrate External Current Programming Voltage Reading Gain This procedure calibrates only the input voltage reading of the External Progr
8. nn nnnn lt current gt Specifies the output current setting 0 0000 70 1000A Sets the current value that the output will ramp to at the present ramp rate Setting value is limited by LIMIT SETI Output Current Setting Query Input SETI term Returned lt current gt term Format Enn nnnn Refer to command for description Key Begins common interface command 2 Required to identify queries aa String of alpha numeric characters tnn String of number characters that may include a decimal point term Terminator characters LS Indicated a parameter field many are command specific lt state gt Parameter field with only On Off states 5 28 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual Table 5 9 Command Summary Command Function Page Command Function vooocconcnnoonnonoricionisnonicnonionorienisienecoss Page CLS Clear Interface Cmd cooooconoccconoccnonacanonncnnnono 29 INTWR Internal Water Mode Ouer 33 ESE Event Status Enable Cd 29 KEYST Keypad Status Query c cooconcococccococnconacanonnnono 33 ESE Event Status Enable Ouer 30 LIMIT Limit Output Settings Cmd eee 34 ESR Event Status Register Query ceeee 30 LIMIT Limit Output Settings Ouer 33 IDN Identification Query oooonoccnociccniccnoccnoninnnns 30 LOCK Keypad Lock Cmd eeeceeeeseeeeeeteereene 34 OPC Operation Complete Cd 30 LOCK Keypad Lock Ouermg 34 OPC Operat
9. Remote operations via the IEEE 488 interface or the Remote key The Local key will take the instrument out of Remote operation and place it in Local operation During Remote operations the Remote LED annunciator will be illuminated and operations from the keypad will be disabled 5 1 3 IEEE 488 Command Structure The Model 642 supports several command types These commands are divided into three groups 1 Bus Control Refer to Paragraph 5 1 3 1 a Universal 1 Uniline 2 Multiline b Addressed Bus Control 2 Common Refer to Paragraph 5 1 3 2 3 Device Specific Refer to Paragraph 5 1 3 3 4 Message Strings Refer to Paragraph 5 1 3 4 5 2 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 3 1 Bus Control Commands A Universal Command addresses all devices on the bus Universal Commands include Uniline and Multiline Commands A Uniline Command Message asserts only a single signal line The Model 642 recognizes two of these messages from the BUS CONTROLLER Remote REN and Interface Clear IFC The Model 642 sends one Uniline Command Service Request SRQ REN Remote Puts the Model 642 into remote mode IFC Interface Clear Stops current operation on the bus SRQ Service Request Tells the bus controller that the Model 642 needs interface service A Multiline Command asserts a group of signal lines All devices equipped to imp
10. 23 CONNECTING THE MAGNET Connecting the magnet to the power supply requires three separate circuits the cooling water hoses the main high current power lines and the safety switches which may include any combination of temperature and flow switches These connections are shown below 2 3 1 Water Hose Connection Water cooling is essential for these magnets The power dissipated can raise the temperature of the coils to the point where they will be destroyed In addition the samples being tested may exhibit changes in their magnetic performance with changes in temperature causing errors in the collected data Typical water connection is shown in Figure 2 2 The magnets may be supplied with hose barbs or standard hose fittings The coils are connected in parallel so that the water temperature rise is the same for both Every effort should be made to insure that the flow rate in both coils is the same The minimum flow required is usually specified by the magnet vendor MAGNET COIL MAGNET WATER CONNECTION GE HOSE BARB FITTING i HOSE CLAMP REENFORCED HOSE OPTIONAL FLOW SWITCH HOSE BARB FITTING HOSE CLAMP lt ZJ KE WATER VALVE Pas S REENFORCED HOSE WATER FILTER Figure 2 2 Typical Magnet Water Hook Up 2 3 2 Magnet Coil Wiring Typical magnet coil wiring is shown in Figure 2 3 The connecting cable used should be of sufficient gage to prevent excessive voltage drop and heat rise in the cable The cables should
11. 5019 IEC 417 No 5020 IEC 417 No 5021 IEC 417 No 5007 IEC 417 No 5008 IEC 417 No 5172 ISO 3864 No B 3 6 Bcakground color yellow Symbol and outline black IEC 417 No 5041 Background color yellow Symbol and outline black ISO 3864 No B 3 1 Background color yellow Symbol and outline black IEC 417 No 5268 a IEC 417 No 5269 a IEC 1010 1 Description Direct current Alternating current Both direct and alternating current Three phase alternating current Earth ground TERMINAL PROTECTIVE CONDUCTOR TERMINAL Frame or chassis ground Equipotentiality On supply Off supply Equipment protected by DOUBLE INSULATION OR REINFORCED INSULATION Caution risk of electric shock Caution hot surface Caution refer to accompanying documents In position of bistable push control Out position of bistable push control Fuse Introduction 1 9 Lake Shore Model 642 Electromagnet Power Supply User s Manual This Page Intentionally Left Blank Introduction Lake Shore Model 642 Electromagnet Power Supply User s Manual CHAPTER 2 MAGNET SYSTEM DESIGN INSTALLATION AND OPERATION 2 0 GENERAL This chapter provides the user insight into the design installation and operation of a typical electromagnet For information on how to install the Model 642 please refer to Chapter 3 For Model 642 operation information refer to Chapter 4 2 1 INTRODUCTION A magnet used
12. Cancel Figure 5 7 GPIBO Setting Configuration System Properties General Device Manager Hardware Profiles Performance I View devices by type CIE National Instruments GPIB Interfaces Properties 27 x E Computer General Device Templates CDROM 2 53 Disk drives y National Instruments GPIB Interfaces o BR Display adapters Floppy disk controllers 3 Hard disk controllers Device Name H Keyboard Monitor 2 Mouse ERA National Instruments GPIB Interface P 89 Network adapters DEN eae y Ports COM amp LPT Interface m Termination Methods Timeouts Si 2 System devices Jee zl Send EOI atend of write Ga A 10sec bed GPIB Address M Terminate Read on EOS Soe Primary MV Set EDI with EOS on Write bo y sec y Properties Refresh R IT 8 bit EOS Compare Secondary none y fio EOS Byte MV Readdress Figure 5 8 DEV 12 Device Template Configuration Computer Interface Operation 5 15 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 5 2 Visual Basic IEEE 488 Interface Program Setup This IEEE 488 interface program works with 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 It assumes your IEEE 488 GPIB card is installed and opera
13. Main code section Used to return response Terminators Data string sent to instrument Device number used with IEEE Show main window Terminators are lt CR gt lt LF gt Clear return string Initialize the IEEE device Setup Repeat Addressing Do Do Wait loop DoEvents Give up processor to other events Loop Until gSend 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 amp term Send command to instrument If ibsta And EERR Then Check for IEEE errors do error handling if needed Handle errors here End If If InStr strCommand lt gt 0 Then Check to see if query strReturn Space 100 Build empty return buffer Call ibrd intDevice strReturn Read back response If ibsta And EERR Then Check for IEEE errors do error handling if needed Handle errors here End If If strReturn lt gt Then Check if empty string strReturn RTrim strReturn Remove extra spaces and Terminators Do While Right strReturn 1 Chr 10 Or Right strReturn 1 Chr 13 strReturn Left strReturn Len strReturn 1 Loop Else strReturn No Response Send No Response End If frmIEEE txtResponse Text strReturn Put response in text on main form End If Loop
14. NOTE The computer interface has a remote operation mode that may be mistaken for a locked keypad If the front panel Remote LED is lit press the Local key to change to local control of the instrument Operation 4 9 Lake Shore Model 642 Electromagnet Power Supply User s Manual Locking the Keypad Continued To lock or unlock the instrument keypad press and hold the Enter key for 5 seconds The following setup screen appears as a prompt for the keypad lock mode Use the A or Y key to select the keypad lock mode Unlock Lock All or Lock Limits Press Enter to choose the new selection and continue to the keypad lock code verification The change to the keypad lock mode is not made until the correct keypad lock code has been entered Press Escape to cancel the new selection and return to the normal display Once the keypad lock mode has been selected the keypad lock code must be entered to accept the change The following screen appears as a prompt for the keypad lock code number entered Ifthe code entered Steg the lock code the display will show 4 oe lock mode wil be updated If the code entered does not match the lock gode the display will how g he gt and the keypad lock mode will not change W i 4 17 COMPUTER INTERFACE There are two computer interfaces on the Model 642 a serial RS 232C interface and an IEEE 488 interface These interfaces are used to connect the instrument to a comp
15. Places the Model 642 into external program mode where the output current is set by an external voltage External Program Mode Query XPGM term lt mode gt term n Refer to command for description Computer Interface Operation 5 37 Lake Shore Model 642 Electromagnet Power Supply User s Manual This Page Intentionally Left Blank 5 38 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual CHAPTER 6 OPTIONS AND ACCESSORIES 6 0 GENERAL This chapter provides information on accessories available for the Model 642 Electromagnet Power Supply 6 1 ACCESSORIES INCLUDED Part Number MAN Model 642 Model 642 Electromagnet Power Supply User s Manual 6031 Two front handles 6032 Two rear handles 6051 Terminal Block 4 Pin 6052 Terminal Block 8 Pin 6252 15 pin D sub mating connector analog I O 108 654 Strain Relief Bushing Kit Calibration Certificate 6 2 ACCESSORIES AVAILABLE Part Number 6201 TEEE 488 Cable Kit 1 meter 3 foot IEEE 488 GPIB computer interface cable assembly 6261 Magnet Cable Kit 3 meters 10 feet 60 A AWG 4 6262 Magnet Cable Kit 6 meters 20 feet 60 A AWG 4 6041 Flow Switch 6042 Solenoid Water Valve with Bracket CAL 642 CERT Instrument recalibration with certificate CAL 642 DATA Instrument recalibration with certificate and data Options and Accessories 6
16. To set the breaker trip current open the access cover on the circuit breaker and adjust the current setting dial to the correct value See Figure 3 3 NOTE The circuit breaker has an automatic reset feature If the breaker trips it will reset within a few minutes and the unit can be restarted If the units trips again after a short time the trip current may be set incorrectly oO D E y je J g S mM A 2 3 9 o E 2 0 E Z lO 4 78 VNS CN N A N 4 E et 8 2 a 9 lt ke e J E o mM Ka ei st no o SO L we DA ye Tech 0 no SC a LY y Z N AITA NS v ACCESS COVER j K CURRENT SETTING DIAL Figure 3 3 Circuit Breaker 3 4 Installation Lake Shore Model 642 Electromagnet Power Supply User s Manual 3 3 3 Start up Fuses The start up transformer and associated circuitry are energized whenever the power is connected To protect this circuitry two Y A class CC fuses are provided A fuse is accessed by pulling open the access door on the fuse holder as shown in Figure 3 4 The fuses are inserted small end first as shown ACCESS DOOR H CLASS CC 1 4 A FUSE FUSE HOLDER Figure 3 4 Fuses 3 3 4 Cable Entry A 34 mm 1 3 inch diameter hole is provided for the power cable to enter the unit A bushing is provided which will accommodate a 16 19 mm 0 62 0 75 in round neoprene jacketed cable See Chapter 6 If a different cable is used a strain relie
17. second Ves ampere A Magnetic Flux maxwell Mx Gecm Magnetic potential difference magnetomotive force gilbert Gb 10 47 Magnetic field strength magnetizing force oersted Oe Gb cm 10 4n Alm Volume magnetization emu cm A m G z 5 107 41 emu cm An x 10 Volume magnetization Magnetic polarization intensity of magnetization A T Wb m 1 Aem kg An x 107 Wb m kg 103 Asm joule per tesla J T H Mass magnetization emu g Magnetic moment emu erg G An x 10 Magnetic dipole moment emu erg G dimensionless emu cm Henry per meter 4n x 107 H m Wb A m An x 10 m kg 4m2 x 101 Hem kg An x 10 m mol 4m x 10 Hem mol An x 107 H m Wb A m dimensionless Volume susceptibility E A IB 7 5 Mass susceptibility Xp cm g emu g 3 Molar susceptibility Xmob Kmol cm mol emu mol Permeability dimensionless Relative permeability not defined Volume energy density 3 1 3 energy product erg cm 10 Jim dimensionless 1 47 dimensionless J Demagnetization factor NOTES a Gaussian units and cgs emu are the same for magnetic properties The defining relation is B H 47M b Multiply a number in Gaussian units by C to convert it to SI e g 1 G x 10 T G 10 T c SI Syst me International d Unit s has been adopted by the National Bureau of Standards Where two conversion factors are given the
18. see Magnetization Measured in SI units as A m and in cgs units as emu 1 emu 107 Am 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 cm 1 emu cm 10 A m Since the mass of a sample is generally much easier to determine than the volume magnetization is often alternately expressed as a mass magnetization defined as the moment per unit mass microcontroller A microcomputer microprocessor or other equipment used for precise process control in data handling communication and manufacturing MKSA System of Units A system in which the basic units are the meter kilogram and second and the ampere is a derived unit defined by assigning the magnitude 4m x 10 to the rationalized magnetic constant sometimes called the permeability of space negative temperature coefficient NTC Refers to the sign of the temperature sensitivity For example the resistance of a NTC sensor decreases with increasing temperature National Institute of Standards and Technology NIST Government agency located in Gaithersburg Maryland and Boulder Colorado that defines measurement standards in the United States noise electrical Unwanted electrical signals that produce und
19. 1 Lake Shore Model 642 Electromagnet Power Supply User s Manual This Page Intentionally Left Blank 6 2 Options and Accessories Lake Shore Model 642 Electromagnet Power Supply User s Manual CHAPTER 7 SERVICE 7 0 GENERAL This chapter provides basic service information for the Model 642 Superconducting Magnet Power Supply Customer service of the product is limited to the information presented in this chapter Factory trained service personnel should be consulted if the instrument requires repair 7 1 CONTACTING LAKE SHORE CRYOTRONICS If a Lake Shore product was purchased through a dealer or representative please use that resource for prompt sales or service information When contacting Lake Shore directly please specify the name of a department if do not know the name of an individual Questions regarding product applications price availability and shipments should be directed to sales Questions regarding instrument calibration or repair should be directed to instrument service Do not return a product to Lake Shore without a Return Authorization number Refer to Paragraph 7 2 Current contact information can always be found on the Lake Shore web site www lakeshore com Lake Shore Cryotronics Inc Instrument Service Department Mailing Address 595 McCorkle Blvd Westerville OH USA 43082 8888 Ben Address So icoGilakeshorecom Instrument Service Telephone 614 891 2244 Sales 614 8
20. 15 3 16 4 1 4 2 5 1 5 2 5 3 5 4 5 5 5 6 5 7 5 8 5 9 7 1 7 2 7 3 7 4 7 5 7 6 7 7 7 8 7 9 7 10 7 11 7 12 LIST OF ILLUSTRATIONS Title Page Model 642 Front Panel iii A As 1 2 A TypicalElecttOMagNetd iii A A e A e 2 1 Typical Magnet Water Hook Up 2 2 Typical Magnet Coil Wiring Showing Series and Parallel Connechons 2 3 Typical Thermal Switch Flow Switch and Valve Wiing 2 4 Typical Curves of Field vs Current for Various Air Gaps and Pole Cap Sizes ooooooncccncccioncccncncionnconccnnnos 2 5 Mocel GZ ear Panel iii 3 3 Voltage Change Detail nsira iene n e aaa sees 3 4 ll ege 3 4 FUSS uegegsbzet ethical ae tb da da 3 5 Typical Cable E try with BUSHINO 22m 3 5 Typical Power laput elt Te ise ata 3 6 Wiring GoverInstallatiOn e curia ito 3 6 Typical Magnet Connector WiIring eecceeesceeeneeceeeeeeneeeeaeeseaeeseaeesaeeseaeeseaeeseaeeseaeeseaeeseaeeseaeeseeseaeeeetenias 3 7 Typical Auxiliary Connector Wiring eeeceeeeeeeeneeeeneeeeneeeeaeeseaeeseaeesaeeseaeeseaeeseaeeseaeeseaeeseaeeseaeeeaeeseeeeeaeenaas 3 7 Typical Power Supply Connector WiriNQ ooocnnccnnnccnnnccnnncnnoncnnonncnnncnnnnn crono crac rar r anna 3 8 Typical Water Hose Connection ooooconccccnccconcccconcnonancnonononnnncnnonnnnnncnn cnc ana nn nen r nn r nene nen rn nera nana carr canna nan 3 8 Water Valve Connection citant Bln ieee deed ele teed tele eso eg geg ed Negi 3 9 Output iCable Connectioni 08 2 nua ic tt nd ree 3 10 Outp
21. Command Input CALG lt type gt lt value gt term Format nn nnnnnnn lt input gt Specifies the item to calibrate Valid entries are 0 Output I Reading 1 Bias A Reading 2 Bias B Reading 3 Gnd Diff Reading 4 Out Con Reading 5 Output V Reading 6 Boost V Reading 7 Ext Prog Input Reading 8 Temp Reading 9 Out Stg V Reading 10 Actual Output Current lt value gt Gain calibration constant value Remarks Items marked with a are for internal diagnostic use only and should always be set to a value of 1 default Service 7 21 Lake Shore Model 642 Electromagnet Power Supply User s Manual CALG Gain Calibration Constant Query Input CALG lt type gt term Format nn lt type gt 0 10 Returned lt value gt 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 CALZ Zero Offset Calibration Constant Command Input CALZ lt type gt lt value gt term Format nn nnnnnnn lt type gt Specifies the item to calibrate Valid entries are 0 Output I Reading 1 Bias A Reading 2 Bias B Reading 3 Gnd Diff Reading 4 Out Con Reading 5 Output V Reading 6 Boost V Reading 7 Ext Prog Input Reading 8 Temp Reading 9 Out Stg V Reading 10 Actual Output Current lt value gt Zero offset calibration c
22. EWECH Status Enable Not Not Not ESE ESE ave det Figure 5 2 Standard Event Status Register 5 8 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 4 2 2 Operation Event Register Set The Operation Event Register reports the following instrument events ramp done compliance Any or all of these events may be reported in the operation event summary bit through the enable register see Figure 5 3 The Operation Event Enable command OPSTE programs the enable register and the query command OPSTE reads it OPSTR reads the Operation Event Register OPST reads and clears the Operation Condition register The used bits of the Operation Event Register are described as follows Power Limit Bit 2 This bit is set if the output is in power limit Ramp Done Bit 1 This bit is set when the output current ramp is completed Compliance Bit 0 This bit is set if the output is in compliance limit Operation Condition 7 6 5 4 3 Bit poe 3 a OPST Used Used Used Used U el EES EA Event 7 6 5 4 3 2 7 o Bit 3 2 Register Not Not Not Not Not SE PRLM raw come Name To Bit 7 OSB of Status Byte Register See Figure 5 1 Operation wotee EECH EZ A E E A Register Not Not Not Not Not OPSTE prim Raw oer Name OPSTE Figure 5 3 Operation Event Register Computer Int
23. End Sub 5 18 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual National Instruments GPIBO Configuration GPIB PC2 2A Ver 2 1 Primary GPIB Address Select the primary GPIB address by Secondary GPIB Address using the left and right arrow keys Timeout setting This address is used to compute the Terminate Read on EOS talk and listen addresses which Set EOI with EOS on Writes identify the board or device on the Type of compare on EOS i GPIB Valid primary addresses range from 0 to 30 00H to 1EH Send EOI at end of Write Adding 32 to the primary address System Controller forms the Listen Address LA Assert REN when SC Adding 64 to the primary address Enable Auto Serial Polling forms the Talk Address TA Enable CIC Protocol EXAMPLE Selecting a primary address Parallel Poll Duration of 10 yields the following Use this GPIB board ES 10 32 42 Listen address y 10 64 74 Talk address Base I O Address Fl Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board National Instruments DEV12 Configuration GPIB PC2 2A Ver 2 1 Primary GPIB Address bh Select the primary GPIB address by Secondary GPIB Address using the left and right arrow keys Timeout setting Serial Poll Timeout This address is used to compute the talk and listen addresses which Terminate Read on EOS identify the board or device on the Set EOI with EOS on Writes GPIB Vali
24. HOSE BARB FITTING REINFORCED HOSE OMBAC PANEL OF bag ADJUSTABLE HOSE CLAMP Figure 3 11 Typical Water Hose Connection Figure 3 12 shows the connections required when a water valve is used The optional solenoid water valve is supplied mounted to a bracket which mounts to the rear of the Model 642 as shown in Figure 3 12 Hose connections are made as shown in Figure 3 11 3 8 Installation Lake Shore Model 642 Electromagnet Power Supply User s Manual ASS N SOLENOID VALVE WITH MOUNTING BRACKET ADJUSTABLE HOSE CLAMP EH REINFORCED HOSE 230 mm 9 in LONG e OM Es Figure 3 12 Water Valve Connection 3 8 MAGNET CABLE CONNECTIONS Magnet cable connections are made at the OUTPUT and terminals on the rear panel These plated copper bus bars accommodate M6 4 inch mounting hardware Two 4 20 bolts nuts and Belleville washers are provided Use load wires heavy enough to limit the voltage drop to less than 0 5 volts per lead This ensures proper regulation and keeps the cables from overheating while carrying the required output current Table 3 3 lists the current capacity and lead lengths for load connections Lake Shore sells magnet cables in 10 and 20 foot lengths Refer to Paragraph 6 2 for ordering accessories Figure 3 13 shows how the output cables are connected to the Model 642 A plain washer and a spring or Belleville washer are provided The Belleville washer is required to maintain contac
25. If Loop End Sub Private Sub Timerl Timer frmSerial Timerl Enabled End Sub False Main code section Used to return response Temporary character space Terminators Counter used for Timing out Data string sent to instrument Show main window Terminators are lt CR gt lt LF gt Initialize counter Clear return string Clear holding string Close serial port to change settings Example of Comm 1 Example of 9600 Baud Parity Data Stop Read one character at a time Open port Wait loop Give up processor to other events Loop until Send button pressed Set Flag as false Get Command Clear response display Set all characters to upper case Get out on EXIT Send command to instrument Check to see if query Wait for response Add 1 to timeout if no character Wait for 10 millisecond timer False Timeout at 2 seconds Reset timeout for each character Read in one character Add next character to string Get characters until terminators Check if string empty Term 1 Strip terminators Send No Response Put response in textbox on main form Reset holding string Reset timeout counter Routine to handle Timer interrupt Turn off timer 5 26 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 2 7 2 Program Operation Once the example program is running try the following commands and observe the response o
26. Model 642 output current reading by front panel or interface and record I reading Calculate the zero offset constant Treading V shun Rshunt Send CALZ 0 zero offset constant Verify the Model 642 output current reading to match the actual output current within 0 0005 mA Send CALSAVE to write this calibration to non volatile memory EE eg Service 7 17 Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 13 3 3 Calibrate Output Voltage Reading Zero This step assumes that the previous two steps are successful and the current through the shunt resistor is quite low resulting in virtually no voltage across the Model 642 output terminals 1 Send CALZ 5 0 to set the current reading offset constant to 0 2 Get the Model 642 output voltage reading by front panel or interface 3 Calculate zero offset constant output voltage reading 4 Send CALZ 5 zero offset constant 5 Verify the Model 642 output voltage reading to be 0 0 001 V 6 Send CALSAVE to write this calibration to non volatile memory 7 1 2 3 11 3 4 Calibrate External Programming Voltage Reading Zero Short the external current programming input lines pins 3 and 11 of the Analog I O connector Send CALZ 7 0 To set the external programming voltage reading constant to 0 Get the Model 642 external programming voltage reading NOTE To get this reading from the Model 642 pre
27. P I R If the current remains constant the power dissipated will rise proportionately with the rise in resistance The Model 642 allows the user to set a maximum current limit to prevent damage to the magnet Refer to Section 4 11 1 EM4 HVA 2 5 cm 1 in Pole Face Field Plot 5 mm 0 20 in 10 mm 0 39 in 15 mm 0 59 in 16 3 mm 0 64 in 20 mm 0 79 in 22 9 mm 0 90 in 25 mm 0 98 in 28 4 mm 1 12 in Magnetic Field kG 38 1 mm 1 5 in 50 mm 1 97 in 50 8 mm 2 00 in 75 mm 2 95 in 100 mm 3 94 in 110 mm 4 33 in 0 10 20 30 40 50 60 70 Current A Figure 2 5 Typical Curves of Field vs Current for Various Air Gaps and Pole Cap Sizes Sheet 1 of 3 Magnet System Design 2 5 Lake Shore Model 642 Electromagnet Power Supply User s Manual Magnetic Field kG Magnetic Field kG EM4 HVA 5 1 cm 2 in Pole Face Field Plot 30 5 mm 0 20 in 25 4 10 mm 0 39 in 15 mm 0 59 in 16 3 mm 0 64 in 20 4 20 mm 0 79 in 22 9 mm 0 90 in 25 mm 0 98 in 15 4 28 4 mm 1 12 in 38 1 mm 1 5 in 10 7 50 mm 1 97 in 50 8 mm 2 00 in 75 mm 2 95 in 37 100 mm 3 94 in Z 110 mm 4 33 in 0 0 10 20 30 40 50 60 70 Current A EM4 HVA 7 6 cm 3 in Pole Face Field Plot 5 mm 0 20 in 25 10 mm 0 39 in Si 15 mm 0 59 in 16 3 mm 0 64 in 20 mm 0 79 in 22 9 mm 0 90 in 25 mm 0 98 in 28 4 mm 1 12 in 15 38 1 mm 1 5 in 1
28. Rest M 1 6726 x 10 kg Proton Rest Mass mp 1 0073 u Rest M 1 6749 x 10 kg Neutron Rest Mass m 1 0087 u SCH 2 0679 x 10 Wb Magnetic Flux Quantum 4 1357 x 1015 J Hz C Josephson Frequency Voltage Ratio 483 483 5939 THz V THz V h 2m ee 6369 x 10 Si Hz ke Quantum of Circulation h m 7 2739 x 10 J Hz E 1 Rydberg Constant RA 1 0974 x 10 m Proton Moment in Nuclear Magnetons 2 7928 Bohr Magneton Lp eh 2m 9 2741 x 10 JT Proton Gyromagnetic Ratio 2 6752 x 108 sl T Diamagnetic Shielding Factor Spherical H2O Sample 1 o H 0 1 0000 Molar Mass Constant 8 3144 J mol Kl Molar Volume Ideal Gas Ty 273 15K po 1 atm Vin RT o po 0 0224 m mol Stefan Boltzman Constant o 17 60 k h ci 5 6703 x 10 W m K First Radiation Constant 3 7418 x 10 W m Second Radiation Constant 0 0144 mK Data abbreviated to 4 decimal places from CODATA Bulletin No 11 ICSU CODATA Central Office 19 Westendstrasse 6 Frankfurt Main Germany Copies of this bulletin are available from this office B 2 Units for Magnetic Properties
29. The difference of electric potential between two points of a conductor carrying a constant current of one ampere when the power dissipated between these points is equal to one watt volt ampere VA The SI unit of apparent power The volt ampere is the apparent power at the points of entry of a single phase two wire system when the product of the RMS value in amperes of the current by the RMS value in volts of the voltage is equal to one watt W The SI unit of power The watt is the power required to do work at the rate of 1 joule per second References 1 Sybil P Parker Editor McGraw Hill Dictionary of Scientific and Technical Terms Fifth Edition New York McGraw Hill 1994 IBSN 0 07 113584 7 2 Christopher J Booth Editor The New IEEE Standard Dictionary of Electrical and Electronic Terms IEEE Std 100 1992 Fifth Edition New York Institute of Electrical and Electronics Engineers 1993 IBSN 1 55937 240 0 3 Nelson Robert A Guide For Metric Practice Page BG7 8 Physics Today Eleventh Annual Buyer s Guide August 1994 ISSN 0031 9228 coden PHTOAD A 6 Glossary of Terminology Lake Shore Model 642 Electromagnet Power Supply User s Manual APPENDIX B UNITS FOR MAGNETIC PROPERTIES Table B 1 Conversion from CGS to SI Units Gaussian Conversion ST amp Quantity amp CGS emu Factor CH Rationalized mks Magnetic flux density Magnetic induction gauss OTT tesla T Wb m weber Wb volt
30. Valid entries are 000 999 Locks out all front panel entries operations LOCK 1 123 term Enables keypad lock and sets the code to 123 Keypad Lock Query LOCK term lt state gt lt code gt term n nnn Refer to command for description MAGWTR Magnet Water Mode Command Input Format Example MAGWTR lt mode gt term n lt mode gt 0 Manual Off 1 Manual On 2 Auto 3 Disabled MAGWTR 2 term Places the magnet water mode to Auto which will automatically control the magnet water valve based on the calculated output power MAGWTR Magnet Water Mode Query Input MAGWTR term Returned lt mode gt term Format n Refer to command for description MODE IEEE Interface Mode Command Input MODE lt mode gt term Format n lt mode gt 0 Local 1 Remote 2 Remote with local lockout Example MODE 2 term Places the Model 642 into remote mode with local lockout MODE IEEE Interface Mode Query Input MODE term Returned lt mode gt term Format n Refer to command for description 5 34 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual OPST Input Returned Format Remarks OPSTE Input Format Remarks OPSTE Input Returned Format OPSTR Input Returned Format Remarks RATE Input Format Remarks RATE Input Returned Format RDGI Input Returned Form
31. also Refer to Section 2 4 2 and Section 4 11 1 2 4 ELECTROMAGNET OPERATION This section provides a brief description of the typical operation of an electromagnet For operation of the Model 642 refer to Chapter 4 2 4 1 Air Gap and Pole Caps The first step in setting up a magnet for operation is to select the proper pole caps and adjust the air gap These parameters are determined by the size and shape of the sample and the connections that must be made to the sample Generally a smaller pole face provides a higher field within the air gap A smaller air gap also provides a higher field The pole faces must be selected to accommodate the size of the sample being tested The air gap is selected based on the size of the sample and the other equipment being used The curves for Field versus Current for various air gaps and pole cap sizes for the Lake Shore Model EM4 HVA are shown in Figure 2 5 It also shows that these parameters are not linear This must be taken into account when operating an electromagnet To obtain linearity it is necessary to operate the magnet and power supply under field control Refer to Section 2 4 4 2 4 2 Maximum Current and Power The Model 642 was designed to operate with a magnet load resistance of 0 50 Q but will work with a resistance range of 0 40 Q to 0 60 Q The resistance of a magnet will rise with a rise in temperature and this should be taken into account The power dissipated in the magnet is given by
32. be as short as possible to minimize the voltage drop Current carrying capacities for various sizes of cables and cable lengths are shown in Table 3 3 The connections must be made with the correct size of hardware for the magnet terminal We recommend the use of a spring or Belleville washer for cable terminations When the parts of a connection expand and contract with changes in temperature they tend to loosen A spring washer will reduce this tendency 2 2 Magnet System Design Lake Shore Model 642 Electromagnet Power Supply User s Manual POWER LEAD CROSS CONNECTION WIRING PARALLEL WIRING N POWER LEAD BOLT BELLEVILLE WASHER CABLE CONNECTION MAGNET POWER LUG PLAIN WASHER NUT POWER LEAD CROSS CONNECTION WIRING SERIES WIRING POWER LEAD Figure 2 3 Typical Magnet Coil Wiring Showing Series and Parallel Connections Magnet System Design 2 3 Lake Shore Model 642 Electromagnet Power Supply User s Manual 2 33 Temperature Switches and Flow Switches As discussed in Section 2 3 1 water cooling for the magnet is essential To protect the magnet from damage resulting from an interruption in cooling water a flow switch temperature switches or both should be installed The switches must have a normally closed contact and if multiple switches are used they must be connected in series The switches are then connected to the Flow Switch terminals of the Magnet Connector on the Model 6
33. connecting the Model 642 Serial Interface to various Customer Personal Computers PCs Model 642 to PC Serial Interface PC with DE 9P Model 642 DE 9P Standard Null Modem Cable DE 9S to DE 9S PC DE 9P 5 GND o gt A GND 2 RD in Moa 3 TD ont 3 TD out 2 RD rn 4 DTR out E D DSR in 6 DSR in m _ __ _ 4 DTR out 1 NC as ae 7 RTS out 7 DTR tied to 4 8 CTS in 8 NC 1 DCD in Model 642 to PC Serial Interface PC with DB 25P Model 642 DE 9P Standard Null Modem Cable DE 9S to DB 25S PC DB 25P 5 GND gt _ 7 GND 2 RD in TTA _ TD out 3 TD out sh TF FTN 3 RD in 1 NC 4 RTS out 7 DTR tied to 4 L 5_CTS in 8 NC 8 DCD in 6 DSR in 20 D TR ont 4 DTR w gt 6 DSR in Model 642 to PC Interface using Null Modem Adapter Model 642 DE 9P Null Modem Adapter PC DE 9P 5 GND HA AA gt 5 GND 2 RD in TTT _ 3 TD out 3 TD out TF 2 RD in 1 NC out SG EEN 6 DSR in E 1 DCD in 4 DTR out 6 DSR in 7 DTR tied to Ai gt 8 CTS in 8 NC _ _ __ 7 RTS out 9 NC OD NC NOTE Same as null modem cable design except PC CTS is provided from the Model 642 on DTR 7 10 7 IEEE 488 Parallel Interface Connector Connect to the IEEE 488 Interface connector on the Model 642 rear with cables specified in the IEEE 488 1978 standard doc
34. detachable screw terminal block is provided to connect the optional magnet CONNECTOR water valve power and temperature and or flow switch 7 AUXILIARY An 8 pin detachable screw terminal block is provided to connect the optional Emergency CONNECTOR Stop Remote Fault Indicator Remote Enable and Chassis Ground 8 POWER SUPPLY A 4 pin detachable screw terminal block is provided to connect the optional power CONNECTOR supply water valve power and or flow switch 9 COOLING Two 10 mm 3 8 hose barbs are provided for input and output of cooling water WATER 10 OUTPUT Two output lugs are provided for the magnet cable connections Refer to Paragraph 3 8 TERMINALS and Figures 3 13 and 3 14 for connecting the magnet cables to the instrument A 15 pin D subminiature connector provides output for current and voltage monitoring 11 ANALOG UO SE as well as analog programming input Refer to Paragraph 3 9 and see Figure 7 7 d A 9 pin D subminiature plug wired in DTE configuration is provided for use with RS 12 E 232C serial computer interface Refer to Paragraph 5 2 2 and see Figure 7 11 13 IEEE 488 An IEEE 488 compliant interface connector is provided for use with IEEE 488 parallel INTERFACE computer interface Refer to Paragraph 5 1 and Figure 7 12 14 CHASSIS An earth safety chassis connection is provided to facilitate connection to the magnet CONNECTION frame if noise problems exist 15 Een Two high strength detachable handles are provided to aid in handli
35. display and brightness of 25 the default setting is recommended for most applications To change the display brightness press Display Setup and the brightness setup will appear Use the A or Y key to select brightness 25 50 75 or 100 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 6 SETTING OUTPUT CURRENT The main purpose of the Model 642 Electromagnet Power Supply is to supply a very precise and stable current to a magnet load Before setting output current make sure that the instrument is properly setup for the magnet system that is being used This includes setting up the maximum output current and maximum ramp rate When a new output current setting is entered the supply will ramp to the new setting at the current ramp rate unless limited by the fixed compliance voltage The Ramping LED will be lit while the output current is ramping When the output current setting is entered it will be limited in magnitude by the maximum current setting Refer to Paragraph 4 11 to setup the maximum settings 4 4 Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual Setting Output Current Continued To change the output current setting press the Output Setting key The output current setting value on the normal display will be highlighted to prompt for the new output current setting value
36. errors can never be cleared Refer to Paragraph 5 1 4 3 for a list of error bits ERST Error Status Query Input ERST term Returned lt hardware errors gt lt operational errors gt term Format nnn nnn Remarks The integers returned represent the sum of the bit weighting of the error bits Refer to Paragraph 5 1 4 3 for a list of error bits Use the ERRCL command to clear the operational errors Hardware errors cannot be cleared ERSTE Error Status Enable Command Input ERSTE lt hardware errors gt lt operational errors gt term Format nnn nnn Remarks Each bit has a bit weighting and represents the enable disable mask of the corresponding error bits in the Error Status Register This determines which status bits can set the corresponding summary bits in the Status Byte Register To enable an error bit send the command ERSTE with the sum of the bit weighting for each desired bit Refer to Paragraph 5 1 4 3 for a list of error bits ERSTE Error Status Enable Query Input ERSTE term Returned lt hardware errors gt lt operational errors gt term Format nnn nnn Refer to Paragraph 5 1 4 3 for a list of error bits 5 32 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual ERSTR Error Status Register Query Input ERSTR term Returned lt hardware errors gt lt operational errors gt term Format nnn nnn Remarks The integers returned represent the sum of t
37. gt Text2 Name txtResponse Text lt blank gt Command1 Name cmdSend Caption Send Default True Form Name frmSerial Caption Serial Interface Program Timerl Enabled False Interval 10 12 Add code provided in Table 5 8 a In the Code Editor window under the Object dropdown list select General Add the statement Public gSend as Boolean Double Click on cmdSend Add code segment under Private Sub cmdSend_Click as shown in Table 5 8 c Inthe 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 5 8 d Double Click on the Timer control Add code segment under Private Sub Timerl_Timer as shown in Table 5 8 e Make adjustments to code if different Com port settings are being used 13 Save the program 14 Run the program The program should resemble the following ia Serial Interface Program Type exit to end program Command Response m wm Dei Es 15 Type in a command or query in the Command box as described in Paragraph 5 2 7 2 16 Press Enter or select the Send button with the mouse to send command 17 Type Exit and press Enter to quit Computer Interface Operation 5 25 Lake Shore Model 642 Electromagnet Power Supply User s Manual Table 5 8 Visual Basic Serial In
38. gt Specifies the rate at which the current will ramp at when the output current is in this segment 0 0001 99 999 A s Remarks Ramp segments are used to change the output current ramp rate based on the output current The ramp segment feature needs to be turned on using the RSEG command RSEGS Ramp Segments Parameters Query Input RSEGS lt segment gt term Returned lt current gt lt rate gt term Format nn nnnn n nnnn Refer to command for description SETI Output Current Setting Command Input SETI lt current gt term Format nn nnnn lt current gt Specifies the output current setting 0 0000 70 1000A Remarks Sets the current value that the output will ramp to at the present ramp rate Setting value is limited by LIMIT SETI Output Current Setting Query Input SETI term Returned lt current gt term Format Enn nnnn Refer to command for description 5 36 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual STOP Input Remarks Stop Output Current Ramp Command STOP term This command will stop the output current ramp within two seconds of sending the command To restart the ramp use the SETI command to set a new output current setpoint XPGM Input Format Example XPGM Input Returned Format External Program Mode Command XPGM lt mode gt term n lt mode gt 0 Internal 1 External 2 Sum XPGM 1 term
39. into three groups Instrument Hardware Errors are related to internal instrument circuitry When one of these errors occurs the Fault LED is solidly lit the output setting is set to 0 A current entry will not be allowed and there is no way to clear the error unless power is cycled If one of these error messages persists after power is cycled the instrument requires repair Instrument Hardware Errors are listed in Table 7 2 Operational Errors are related to instrument operation and do not necessarily indicate a hardware problem When one of theses errors occurs the Fault LED will be blinking and the error condition can be cleared once the fault condition has been removed Operational Errors are listed in Table 7 3 User Errors are related to user requests that cannot be processed These errors generate responses that immediately explain the cause of the error These are usually simple order of operation issues and are easily resolved The fault LED is not used for these simpler errors User Errors are self explanatory and are therefore not listed Table 7 2 Instrument Hardware Errors Cold Plate temperature is over 45 C The output setting is set to 0 A and no current Internal Temperature Fault entry will be allowed The error message will flash for 10 seconds then the Model 642 will turn itself off The output voltage is greater than the 44 V compliance voltage limit indicating a problem with the compliance voltage circuitry The
40. key to select one of the following terminators CR LF LF CR LF and EOI The default is CR LF 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 4 18 DEFAULT PARAMETER VALUES It is sometimes desirable to reset instrument parameters to their default values This data is stored in nonvolatile memory called EEPROM Instrument calibration is not affected by this operation Firmware version information for the main firmware and the DAC firmware is also displayed during this sequence To clear EEPROM memory or view the firmware versions press and hold the Escape key for 5 seconds The following screen appears to show the main firmware version the DAC processor firmware version and as a prompt for returning the instrument parameters to default values Default parameter values are listed in Table 4 3 Use the A or Y key to select Yes for default values and No to continue without changing the parameter values 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 Operation 4 11 Lake Shore Model 642 Electromagnet Power Supply User s Manual Table 4 3 Default Parameter Values Output Settings Output Current 2 0 eee eeeeeteereereeees DA Current Ramp Rate 99 999 A s Maximum Settings Max Output Cumremt eee 70 1 A Max
41. on the sample geometry and orientation with respect to the field deviation The difference between the actual value of a controlled variable and the desired value corresponding to the setpoint differential permeability The slope of a B versus H curve ua dB dH differential susceptibility The slope of a M versus H curve a dM dH digital controller A feedback control system where the feedback device sensor and control actuator heater are joined by a digital 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 dimensionless sensitivity Sensitivity of a physical quantity to a stimulus expressed in dimensionless terms The dimensionless temperature sensitivity of a resistance temperature sensor is expressed as Sa T R dR dT which is also equal to the slope of R versus T on a log log plot that is Sy d InR d InT Note that the absolute temperature in Kelvin must be used in these expressions drift instrument An undesired but relatively slow change in output over a period of time with a fixed reference input Note Drift is usually expressed in percent of the maximum rated value of the variable being measured electromagnet A device in which a magnetic field is generated as the result of electrical current passing through a helical conducting coil It can be configured as
42. or 1 26 gilberts ampere meter A m The SI unit for magnetic field strength H 1 ampere meter 47 1000 oersted 0 01257 oersted analog controller A feedback control system where there is an unbroken path of analog processing between the feedback device sensor and control actuator heater analog data Data represented in a continuous form as contrasted with digital data having discrete values analog output A voltage output from an instrument that is proportional to its input For example from a digital voltmeter the output voltage is generated by a digital to analog converter so it has a discrete number of voltage levels autotuning In Lake Shore instruments the Autotuning algorithm automatically determines the proper settings for Gain Proportional Reset Integral and Rate Derivative by observing the time response of the system upon changes in setpoint B Symbol for magnetic flux density See Magnetic Flux Density bar Unit of pressure equal to 10 pascal or 0 98697 standard atmosphere Baud A unit of signaling speed equal to the number of discrete conditions or signal events per second or the reciprocal of the time of the shortest signal element in a character bit A contraction of the term binary digit a unit of information represented by either a zero or a one BNC Bayonet Nut Connector Glossary of Terminology A 1 Lake Shore Model 642 Electromagnet Power Supply User s Manual boili
43. requires 311 mm 12 25 in 7U in height At least 25 mm 1 in of space should be provided on each side for cross ventilation No ventilation panels are required above or below the unit Due to the weight of the power supply it is recommended that the supply be located at the bottom of the rack and that it rest on the bottom panel of the rack If the rack does not have a bottom panel a shelf capable of supporting 74 kg 163 Ib must be provided Light duty support rails which bolt to the sides of the front and rear mounting rails of the rack are not strong enough to support this unit In addition if the equipment rack which houses the Model 642 is to be shipped the Model 642 must be anchored to the shelf Threaded inserts are provided in the bottom of the Model 642 for this purpose Four 4 20 x 1 2 in bolts not included are required The hole pattern for mounting is shown in Figure 3 16 CAUTION The front panel rack mount is to be used only to secure the power supply to the front of the rack The bottom of the rack or the equipment shelf must support the entire weight of the supply Do NOT attempt to support the supply from the front mounting holes alone Figure 3 16 Mounting Hole Pattern 3 12 Installation Lake Shore Model 642 Electromagnet Power Supply User s Manual CHAPTER 4 OPERATION 4 0 GENERAL This chapter provides operating instructions for the features of the Model 642 Electromagnet Power Suppl
44. resistor remains connected in series with the magnet load for this procedure Send CALG 10 0 To set the output current gain trim constant to 0 Set the Model 642 output current to 65 A ramp rate 30 A s nominal Wait 30 seconds for settling Measure the actual voltage across the shunt and record V hunt Calculate and record Imax Wshunt Rshunt Send CALG 10 100 To set the output current gain trim constant to maximum Wait 10 seconds Measure the actual voltage across the shunt and record V hunt SOOO ON A ee oS Calculate and record Imaxpostrim V shunt Rshunt 10 Send CALG 10 100 To set the output current gain trim constant to minimum 11 Wait 10 seconds 7 18 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual Calibrate Output Current Gain Continued 12 Measure the actual voltage across the shunt and record Vshunt 13 Calculate and record Iminpostrim V shunt Rshunt 14 Send CALG 10 0 To set the output current gain trim constant to 0 15 Set the Model 642 to 65A V ramp rate 30 A s nominal 16 Wait 30 seconds for settling 17 Measure the actual voltage across the shunt and record Vshunt 18 Calculate and record Lmin Vshunt Rshunt 19 Send CALG 10 100 To set the output current gain trim constant to maximum 20 Wait 10 Seconds 21 Measure the actual voltage across the shunt and record V hunt 22 Calculate and
45. set if the instrument is not calibrated or the calibration data has been corrupted Fee CECR EC EECH see E Condition Register GEN REF pre wee aww uv ope 041 nano pd ica RO RCN ESE EZ EC E E IN Event Register castas REF PrF mer rev cv vs Jere ca nano To Bit 1 OESB of Status Byte Register See Figure 5 1 AND Error Status 7 4 3 1 o 17 6 Bit Enable Register ERSTE ERSTE uv TH ere cat fname Figure 5 5 Operational Error Status Register Computer Interface Operation 5 11 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 4 4 Status Byte and Service Request SRQ As shown in Figure 5 1 the Status Byte Register receives the summary bits from the two status register sets and the message available summary bit from the output buffer The status byte is used to generate a service request SRQ The selection of summary bits that will generate an SRQ is controlled by the Service Request Enable Register 5 1 4 4 1 Status Byte Register The summary messages from the event registers and output buffer set or clear the summary bits of the Status Byte Register see Figure 5 5 These summary bits are not latched Clearing an event register will clear the corresponding summary bit in the Status Byte Register Reading all messages in the output buffer including any pending queries will clear the mes
46. some typical Power Supply Connector wiring FLOW FLOW cr FLOW FLOW SWITCH SWITCH gt o SWITCH SWITCH D WATER WATER J Lg WATER WATER E VALVE VALVE E o VALVE VALVE NO VALVE OR SWITCH VALVE ONLY SWITCH ONLY VALVE AND SWITCH Figure 3 10 Typical Power Supply Connector Wiring 3 7 COOLING WATER Two 10 mm 0 38 in hose barbs are provided to connect to cooling water The connection to the cooling water source should be made with two 10mm 3 8 in I D fiberglass reinforced hoses and two 20mm 25 32 in adjustable hose clamps In addition we recommend the installation of a sediment filter in the input line A typical water hose connection is shown in Figure 3 11 The cooling water must be clean and free from sediment salt and other contaminants which might clog or erode the water fittings A minimum flow rate of 5 7 L 1 5 gal per minute is required with a minimum pressure of 34 kPa 5 psi and a maximum pressure of 552kPa 80 psi The temperature must be kept above 15 C to avoid condensation and below 30 C to ensure adequate system cooling If water is drawn from a local municipal water source the optional water valve should be installed for economy and to prevent condensation See 3 6 Power Supply Connector If water is supplied by a facility chiller a valve can still be used but is not required CAUTION Dot use de ionized water because it is corrosive to the water fittings inside the Model 642
47. suggested 7 11 3 Calibration Procedure The following calibration steps should be performed exactly in the order provided Pay close attention to the use of CALZ vs CALG commands They can easily be confused and will certainly create unexpected results if accidentally interchanged Zeroing calibrations use CALZ commands while Gain Span calibrations use CALG commands 7 11 3 1 Calibrate Current Output Zero The 1 mQ shunt resistor is wired in series with the calibration load from the positive output terminals with 4 AWG wire Cable length is relatively unimportant but should be less than 5 feet to the shunt resistor Voltage across the shunt resistor is to be monitored by the DVM The DVM input connections must both be isolated from earth power line ground Send CALZ 10 0 to set the output offset constant to 0 Set the Model 642 output current to 0 A Measure the actual voltage across the shunt and record V hunt Calculate the zero offset constant V shunt Rshunt Send CALZ 10 zero offset constant Reset the Model 642 output current to 0 A loads the new offset setting Verify the actual output current to be less than 1 mA Send CALSAVE to write this calibration to non volatile memory NY O OO E SE ki 11 3 2 Calibrate Current Reading Zero Send CALZ 0 0 to set the current reading offset constant to 0 Measure the actual voltage across the shunt and record N Ausl Get the
48. the Object dropdown list select General Add the statement Public gSend as Boolean Double Click on cmdSend Add code segment under Private Sub cmdSend_Click as shown in Table 5 5 c Inthe 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 5 5 13 Save the program 14 Run the program The program should resemble the following IEEE Interface Program Type exit to end program Command lel Es Response 15 Type in a command or query in the Command box as described in Paragraph 5 1 5 5 16 Press Enter or select the Send button with the mouse to send command 17 Type Exit and press Enter to quit Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual Table 5 5 Visual Basic IEEE 488 Interface Program Public gSend As Boolean Global used for Send button state Private Sub cmdSend Click gSend True End Sub Private Sub Form Load Dim strReturn As String Dim term As String Dim strCommand As String Dim intDevice As Integer frmIEEE Show term Chr 13 amp Chr 10 strReturn Call ibdev 0 12 0 T10s 1 amp H140A intDevice Call ibconfig intDevice ibcREADDR 1 Routine to handle Send button press Set Flag to True
49. the new selection and return to the normal display To avoid discontinuities in the output current the external current programming mode cannot be changed if the programming voltage is not zero or the front panel current setting is not zero If the external current program mode is going to be kept from changing an error box will pop up explaining why the new setting is being ignored This error box is shown below 4 16 LOCKING THE KEYPAD The keypad lock feature prevents accidental changes to parameter values When the keypad is locked parameter values may be viewed but cannot be changed from the front panel The Model 642 has two keypad lock modes The lock all mode locks out changes to all parameters The lock limits mode locks out changes to all of the parameters except Output Setting Ramp Rate Zero Output and Pause Ramp This allows the power supply to be operated without allowing any changes to the power supply setup A 3 digit code must be used to lock and unlock the keypad The factory default code is 123 and it can only be changed using a computer interface If the instrument parameters are reset to default values See Default Parameter Values 4 18 the code is reset to the factory default The instrument parameters cannot be reset to default values from the front panel when the keypad is locked The following message box appears on the display if the user attempts to change a parameter while the keypad is locked
50. the next setting screen Press Escape to cancel the new selection and return to the normal display If the ramp segments are enabled the next ramp segments screen that appears is for entering or editing the ramp segments table All five of the ramp segments are shown on the display at the same time The segments should be entered in order of increasing current An entry of 0 A will indicate the end of the table and the instrument will not search beyond that segment E When the segment number is highlighted use the A or Y key to scroll through the ramp segments Press the Enter key when the desired segment number is highlighted and continue to the current field When the current field is highlighted use the numerical keypad to enter the upper current setting for that ramp segment in amps Press Enter to accept the new selection and continue to the ramp rate field Press Escape to restart the setting sequence and enter a new value Press Escape again to highlight the segment number When the ramp rate field is highlighted use numerical keypad to enter the applicable ramp rate in A s Press Enter to accept the new selection and continue to the next segment Press Escape to restart the setting sequence and enter a new value Press Escape again to highlight the segment number Similarly enter or edit all ramp segments When complete press the Escape key while the segment number field is highlighted to exit the ramp segment edit scree
51. the standard event summary bit through the enable register see Figure 5 2 The Standard Event Status Enable command ESE programs the enable register and the query command ESE reads it ESR reads and clears the Standard Event Status Register The used bits of the Standard Event Register are described as follows Power On PON Bit 7 This bit is set to indicate an instrument off on transition Command Error CME Bit 5 This bit is set if a command error has been detected since the last reading This means that the instrument could not interpret the command due to a syntax error an unrecognized header unrecognized terminators or an unsupported command Execution Error EXE Bit 4 This bit is set if an execution error has been detected This occurs when the instrument is instructed to do something not within its capabilities Query Error QYE Bit 2 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 5 1 4 4 6 for more information Ge E EE REE 0 ENN RG Status Register ESR Bit Name AND To bit 5 ESB of Status Byte Register See Figure 5 1 standard Event Z E E a
52. to prevent stray strands from shorting to adjacent terminals Installation 3 5 Lake Shore Model 642 Electromagnet Power Supply User s Manual 140 mm 5 5 in POWER CABLE STRIP 13mm 0 5 in WIRE FERRULE OPTIONAL POWER TERMINALS Figure 3 6 Typical Power Input Wiring 3 3 6 Wiring Cover When the power wiring voltage setting and current setting are complete install the wiring cover with the six 6 6 32 x 3 8 screws provided The wiring cover installation is shown in Figure 3 7 Be sure that the voltage indicator tab of the voltage locator card Figure 3 2 shows through the correct indicator slot in the wiring cover WARNING Do not connect power or attempt to operate the unit with this cover removed Lethal voltage and currents exist inside There is a risk of injury or death if an operator or technician comes in contact with these potentials CHASSIS WIRING COVER A ff 6 32 X 3 8 SCREW f j 6 I age _ VOLTAGE INDICATOR SLOTS Nice i Soe N ei ZS ve Se di d n ZA POWER CORD D ES Figure 3 7 Wiring Cover Installation 3 6 Installation Lake Shore Model 642 Electromagnet Power Supply User s Manual 3 3 7 Mains Wiring No cord or disconnecting plug is provided with the unit In all cases the field connection of the mains wiring shall comply with all local wiring codes where the Model 642 is installed The power source shall be protected with a dedicated circuit break
53. type and rating specified for the line voltage selected Use the following procedure to change the power line fuses Identify the power wiring access panel on the rear of the Model 642 Turn the front panel line power switch OFF O Disconnect the power cable at the plug end for safety Remove the perimeter screws holding the power wiring access panel Locate the two fuse holder assemblies as shown in Figure 7 1 and detailed in Figure 7 4 Pull open the access door to remove a fuse Sc Ow SONS e Gat ee TES Check the fuse for continuity Replace fuse s if necessary Fuses should be replaced in pairs Fuses are inserted small end first as shown Ze Close the fuse access door s 9 Replace the wiring access panel using all perimeter screws 7 4 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual ACCESS DOOR A CLASS CC 1 4 A FUSE FUSE HOLDER KSC Figure 7 4 Fuse Holder Detail 7 6 ERROR MESSAGES The following messages appear on the lower part of the instrument display when it identifies a problem during operation The Fault LED will light in conjunction with the error message A more extensive description of the error message can shown by pressing the Status key If the error condition can be immediately cleared it can be done by pressing the Status key while in the error status display Refer to Paragraph 4 14 for a description of the error status display Error messages are divided
54. uniform magnetic field Introduction 1 1 Lake Shore Model 642 Electromagnet Power Supply User s Manual Output Architecture Continued The Model 642 output architecture relies on low noise linear input and output stages The linear circuitry of the Model 642 permits operation with less electrical noise than switch mode electromagnet power supplies One key benefit of this architecture is CE compliance to the electromagnetic compatibility EMC directive including the radiated emissions requirement Output Programming The Model 642 output current is programmed internally via the keypad externally by the computer interface externally by the analog programming input or by the sum of the external and internal settings For internal programming the Model 642 incorporates a proprietary digital to analog converter DAC that is monotonic over the entire output range and provides a resolution of 0 1 mA The Model 642 generates extremely smooth and continuous ramps with virtually no overshoot The digitally generated constant current ramp rate is variable between 0 1 mA s and 99 999 A s To ensure a smooth ramp rate the power supply updates the high resolution DAC 23 7 times per second A low pass filter on the DAC output smoothes the transitions at step changes during ramping Output Readings The Model 642 provides high resolution output readings The output current reading has a resolution of 0 1 mA The output voltage reading rep
55. upper one is recognized under or consistent with SI and is based on the definition B ul M where to py 47 x 107H m The lower one is not recognized under SI and is based on the definition B uH J where the symbol I is often used in place of J 1 gauss 10 gamma y Both oersted and gauss are expressed as cm ges in terms of base units A m was often expressed as ampere turn per meter when used for magnetic field strength Magnetic moment per unit volume The designation emu is not a unit Foe mee i Recognized under SI even though based on the definition B poH J See footnote c j Hr B po 1 all in SI pt is equal to Gaussian p k Be Hand pM H have SI units J m M H and B H 4n have Gaussian units erg cm R B Goldfarb and F R Fickett U S Department of Commerce National Bureau of Standards Bolder Colorado 80303 March 1985 NBS Special Publication 696 For sale by the Superintendent of Documents U S Government Printing Office Washington D C 20402 Units for Magnetic Properties Lake Shore Model 642 Electromagnet Power Supply User s Manual Table B 2 Recommended SI Values for Physical Constants ET JO ir A TT 0 0073 Fine Structure Constant w0ce2 2h DEE 137 0360 Elementary Charge E 1 6022 x 10 16022x10 C Plank 6 6262 x 10 J Hz ank s Constant A 1 0546 x 10 J s Avogadro s Constant 6 0220 x 10 mol i 0 9109 x 10 kg Electron Rest Mass Me 5 4858 x 10 u
56. with the Model 642 Power Supply is typically an iron pole twin coil 4 inch pole diameter variable air gap water cooled electromagnet Larger magnets can be used depending on their electrical parameters and the magnetic field requirements The electromagnet provides a uniform magnetic field in the air gap between two adjustable poles The samples which are to be tested for their magnetic properties are placed in the air gap with appropriate monitoring equipment attached By varying the polarity and intensity of the field useful data can be collected A typical electromagnet is shown in Figure 2 1 COIL POLE COIL POLE CAP POLE LOCK POLE LOCK POLE ADJUSTER sc POLE ADJUSTER MAGNET FRAME MAGNET BASE Figure 2 1 A Typical Electromagnet Magnet System Design 2 1 Lake Shore Model 642 Electromagnet Power Supply User s Manual 2 2 MAGNET CONSTRUCTION The magnet consists of two water cooled coils surrounding adjustable iron poles which are fitted into an iron frame The frame supports the poles and coils and improves the magnet s efficiency The iron poles are fitted with adjusting mechanisms so that the air gap width can be set Lock mechanisms are provided to hold the poles in place after adjustment is made The poles faces have pole caps attached which provide the desired magnetic focus The size and shape of the pole caps are chosen according to the size of sample being tested and the magnetic field requirement
57. zero The remanence would be the upper limit to values for the remanent induction Note that no strict convention exists for the use of remanent induction and remanence and in some contexts the two terms may be used interchangeably remanent induction The remaining magnetic induction in a magnetic material after an applied field is reduced to zero Also see remanence repeatability The closeness of agreement among repeated measurements of the same variable under the same conditions resistance temperature detector RTD Resistive sensors whose electrical resistance is a known function of the temperature made of e g carbon glass germanium platinum or rhodium iron resolution The degree to which nearly equal values of a quantity can be discriminated 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 10 possible display values A resolution of n and one half digits has 2 x 10 possible values measurement resolution The ability of an instrument to resolve a measured quantity For digital instrumentation this is often defined by the analog to digital converter being used A n bit converter can resolve one part in 2 The smallest signal change that can be measured is the full scale input divided by 2 for any given range Resolution should not be confused with accuracy RhFe Rhodiu
58. 20 Recheck that all connectors have been reinstalled and confirm proper locations and orientations of each 21 Follow the top of enclosure installation procedure of Section 7 8 2 7 8 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual DIGITAL BOARD Cy Figure 7 5 Board Locations top view Service Lake Shore Model 642 Electromagnet Power Supply User s Manual S3IYVONOOAS YAWHOSSNVYL DNIJIIAFSNOH gt Z ar wo 89d POIVNY O a eu Cj E 89d OVIAA 111 278 A 642 DIGITAL PCB c 2006 LSCI cris P Se Joris YSAWYOSSNVHLL NIV aal UC o S ISE ABVIMIXAV veo soll y LaL o odo LOCATOR PINS Figure 7 6 Digital Board Parts Locations YOLOANNOO 3331 7 10 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 10 CONNECTOR AND CABLE DEFINITIONS All non po
59. 373 15 K 100 C 212 F Triple point of water 273 16 K Freezing point of water 273 15 K 0 32 F Absolute zero OK 273 15 C 459 67 F kelvin Celsius Fahrenheit To convert Kelvin to Celsius subtract 273 15 To convert Celsius to Fahrenheit multiply C by 1 8 then add 32 or F 1 8 x C 32 To convert Fahrenheit to Celsius subtract 32 from F then divide by 1 8 or C F 32 1 8 temperature coefficient measurement The measurement accuracy of an instrument is affected by changes in ambient temperature The error is specified as an amount of change usually in percent for every one degree change in ambient temperature tesla T The SI unit for magnetic flux density B 1 tesla 10 gauss thermal emf An electromotive force arising from a difference in temperature at two points along a circuit as in the Seebeck effect tolerance The range between allowable maximum and minimum values torr Unit of pressure 1 torr 1 mm of mercury 1 atmosphere 760 torr two lead Measurement technique where one pair of leads is used for both excitation and measurement of a sensor This method will not reduce the effect of lead resistance on the measurement 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 volt V
60. 42 The Model 642 monitors the switches and if an open is detected the output current is ramped to zero Flow switch monitoring depends on water valve mode setting See sections 4 12 and 4 13 for details Given the cost of the magnet it is prudent to use both temperature and flow switches Some installations use two flow switches one in the exhaust line of each coil so that if a clog occurs in only one coil it can be detected Figure 2 4 shows the typical flow and temperature switch connection CAUTION Care must be used in the selection of the flow switch Some switches use a sensitive reed switch which can be overpowered by stray flux from the magnet and will not open when the magnet is operating at high field The flow switch must be tested by turning off the water while the magnet is operating at full current THERMAL SWITCH Z THERMAL SWITCH gt TO 642 MAGNET CONNECTOR FLOW SWITCH CONTACTS X FLOW SWITCH ei TO 642 MAGNET CONNECTOR VALVE CONTACTS Leg WATER VALVE INLET OUTLET Figure 2 4 Typical Thermal Switch Flow Switch and Valve Wiring 2 3 4 Cooling Water and Water Valve The cooling water for the magnet can be drawn from the municipal water facility or from a dedicated re circulating water chiller designed for this purpose When water is drawn from the municipal water facility the water should be turned on only when it is required to reduce consumption and reduce the likelihood of scale build up i
61. 9 50 mm 1 97 in 50 8 mm 2 00 in 75 mm 2 95 in 100 mm 3 94 in 110 mm 4 33 in 70 Current A Figure 2 5 Typical Curves of Field vs Current for Various Air Gaps and Pole Cap Sizes Sheet 2 of 3 Magnet System Design Lake Shore Model 642 Electromagnet Power Supply User s Manual EM4 HVA 10 2 cm 4 in Pole Face Field Plot 25 5 mm 0 20 in 20 4 10 mm 0 39 in 15 mm 0 59 in 16 3 mm 0 64 in 15 4 20 mm 0 79 in 22 9 mm 0 90 in 25 mm 0 98 in 28 4 mm 1 12 in 38 1 mm 1 5 in 50 mm 1 97 in 50 8 mm 2 00 in 10 4 Magnetic Field kG 75 mm 2 95 in 100 mm 3 94 in 110 mm 4 33 in 0 10 20 30 40 50 60 70 Current A Figure 2 5 Typical Curves of Field vs Current for Various Air Gaps and Pole Cap Sizes Sheet 3 of 3 2 4 3 Operation Under Field Control To obtain a linear field ramp a magnetic sensor such as a Hall probe is placed in the air gap along with the sample being tested The sensor is connected to a Gaussmeter The output of the Gaussmeter is used to correct the programming input to the power supply In this way non linearity can be corrected Lakeshore manufactures probes and Gaussmeters for this purpose Magnet System Design 2 7 Lake Shore Model 642 Electromagnet Power Supply User s Manual 2 4 4 Avoiding Cooling Water Condensation If the temperature of the cooling water is too cool relative to the air temperature and humidity co
62. 91 2243 ext 131 Instrument Service Fax 614 818 1600 Sales 614 818 1609 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 21 7 2 RETURNING PRODUCTS TO LAKE SHORE If it is necessary to return the Model 642 for recalibration repair or replacement a Return Authorization RA number must be obtained from a factory representative or from the Lake Shore web site Do not return a product to Lake Shore without an RA number The following information must be provided to Lake Shore in order to obtain an RA number Instrument model and serial number User name company address phone number and e mail address Malfunction symptoms Po Zu bt k Description of the system in which the product is used If possible the original packing material should be retained for reshipment If not available a minimum of three inches of shock adsorbent packing material should be placed snugly on all sides of the instrument placed in a sturdy corrugated cardboard box The RA number should be included in the mailing label or written prominently on the outside of the box A copy of the customer contact information and RA number should be included inside the box Consult Lake S
63. Common commands all begin with an asterisk They generally relate to bus and instrument status and identification Common query commands end with a question mark Model 642 common commands are detailed in Paragraph 5 3 and summarized in Table 5 8 5 1 3 3 Device Specific Commands Device specific commands are addressed commands The Model 642 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 642 device specific commands are detailed in Paragraph 5 3 and summarized in Table 5 8 5 1 3 4 Message Strings A message string is a group of characters assembled to perform an interface function There are three types of message strings commands queries and responses The computer issues command and query strings through user programs the Instrument issues responses Two or more command strings or queries can be chained together in one communication but they must be separated by a semi colon The total communication string must not exceed 255 characters in length A command string is issued by the computer and instructs the instrument to either perform a function or change a parameter setting When a command is issued the computer is acting as talker and the instrument as listener The format is lt command mnemonic gt lt space gt lt par
64. Denionnicinninnnnccnnnc 5 14 5 1 5 IEEE 488 Interface Example Programs ooooccconncccnnnocccnnncccnonnnacccnnnnrn eran nenes 5 14 5 1 5 1 IEEE 488 Interface Board Installation for Visual Basic Program 5 14 5 1 5 2 Visual Basic IEEE 488 Interface Program Setup cccceeceeeeseeeeeeeeeneeeeeeeteeeseaeeteaeeseaeeseeeenaeene 5 16 5 1 5 3 Program Operativa ii a een id ecb lied 5 20 5 1 6 TOUS MN site eed ee abe ee eee ied ee ee te 5 20 5 2 SERIAL INTERFACE OVERVIEWo te ene taeda tend ee anit is tate nial 5 21 5 2 1 Changing Ba d CHE 5 21 5 2 2 Physical COnnectio Myrsine o ae Metin a it ete 5 21 5 2 3 le Ve GE 5 22 5 2 4 Character Fonmat gue S ee eege EE 5 22 5 2 5 Eine EE EE 5 22 5 2 6 Message Flow Controls seiners ENEE ee danos 5 23 5 2 7 Serial Interface Example Programs ccescceseceeeeeeeneeeeeeeeeseeeeaeeesaeeeeaeesaeeeeaeesaeeseaeessaeeseaeesaeesaas 5 23 5 2 7 1 Visual Basic Serial Interface Program Setup cooocccnnccincccnoncconocanancconncanancnnanc crac cnn nn ran cn ran cn rn 5 24 5 2 7 2 Program OpetatlOn RTE 5 27 5 2 8 PROUDIESMOOUNG BEE 5 27 5 3 COMMAND SUMMARY aaa atraitne haa aa aa r eate aaeeea aa e aa a E Eaa EEEo A aaa E CEA 5 28 5 3 1 Interface Commands Alphabetical Listing cececeseeeeeeeeeeeeeeeeeeeaeeeeaeeseaeeseaeeseaeessaeeseeeesaeenaees 5 29 6 OPTIONS AND ACCESSORIES ic lt lt icomiimciimiircinii o SEENEN Ee 6 1 6 0 GENERAL cuca AA lil gilt adie 6 1 6 1 ACCESSORIES INCLUDED cui
65. Kelvin Scale It is one of the base units of SI The word degree and its symbol are omitted from this unit See Temperature Scale for conversions Glossary of Terminology A 3 Lake Shore Model 642 Electromagnet Power Supply User s Manual Kelvin Scale The Kelvin Thermodynamic Temperature Scale is the basis for all international scales including the ITS 90 It is fixed at two points the absolute zero of temperature 0 K and the triple point of water 273 16 K the equilibrium temperature that pure water reaches in the presence of ice and its own vapor line regulation The maximum steady state amount that the output voltage or current changes as result of a specified change in input line voltage usually for a step change between 105 125 or 210 250 volts unless otherwise specified line voltage The RMS voltage of the primary power source to an instrument load regulation A steady state decrease of the value of the specified variable resulting from a specified increase in load generally from no load to full load unless otherwise specified lock in amplifier An amplifier that uses some form of automatic synchronization with an external reference signal to detect and measure very weak electromagnetic radiation at radio or optical wavelengths in the presence of very high noise levels M Symbol for magnetization See magnetization magnetic air gap The air space or non magnetic portion of a magnetic circuit magnetic f
66. Ki 8 NY EF 2 4 o o S O O Z Z S CON CN JN 3 o Va ei 2 2 a g Y P o et E 0 OF oy E 3 A o e EAS E O 7 S r 9 Y A Z N E J y JS w N el e ACCESS COVER CURRENT SETTING DIAL Figure 7 3 Circuit Breaker 7 Ifincorrect use a small straight blade screwdriver to reset according to Table 7 1 Close the circuit breaker access door 9 Replace the power wiring access panel using all perimeter screws 7 5 POWER LINE FUSE REPLACEMENT The Model 642 uses a low power start up power supply to provide power to the main contactor coil through multiple thermal safety switches The start up supply is energized any time the three phase power input voltage is connected to the Model 642 This section deals with the fuses for this supply If the power line fuses for this supply are open the Model 642 internal three phase contactor will not close and normal operation will not be possible If the Model 642 is connected to an input voltage that is higher than the selected voltage of the Model 642 these fuses are expected to clear and prevent operation of the Model 642 Proper voltage selection must be made before connection to the power mains Access to these fuses is through the power wiring access panel WARNING To avoid potentially lethal shocks turn off the power supply and disconnect it from AC power before performing this procedure CAUTION For continued protection against fire hazard replace only with same fuse
67. Model 642 Electromagnet Power Supply CAUTION To ensure the best possible performance and maintain operator safety read this entire chapter before installing the instrument and applying power Serious hazards can exist when an instrument of this power capacity is used incorrectly If you do not understand any section of this manual consult Lake Shore for clarification Lake Shore Cryotronics assumes no responsibility for damage or injuries incurred due to improper installation defeat of any of the safety features or misuse of this power supply 3 1 INSPECTION AND UNPACKING Inspect shipping containers for external damage before opening them Photograph any container that has significant damage before opening it If there is visible damage to the contents of the container contact the shipping company and Lake Shore immediately preferably within 5 days of receipt of goods Keep all damaged shipping materials and contents until instructed to either return or discard them Open the shipping container and keep the container and shipping materials until all contents have been accounted for Check off each item on the packing list as it is unpacked Instruments themselves may be shipped as several parts The items included with the Model 642 are listed below 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 bo
68. Pin Name Pin Name 1 NC 9 NC 2 Chassis 10 Chassis 3 Current Program 11 Current Program 4 Chassis 12 Chassis 5 Voltage Monitor 13 Voltage Monitor 6 Chassis 14 Chassis T Current Monitor 15 Current Monitor 8 Chassis Figure 3 15 Model 642 Analog Input Output Connector 3 9 1 External Current Programming The output current can be programmed externally using an AC or DC voltage This programming voltage can also be summed with the internal current setting or ramp Refer to Paragraph 4 15 to change the external current program mode The external current programming input is a differential input with a sensitivity of 10 V 70 A and an input impedance of gt 50 kQ The programming voltage is limited internally to approximately 10 1 V Category 1 but care must be taken to insure that maximum current capability of the magnet is never exceeded 3 9 2 Output Current and Voltage Monitors The output current and output voltage of the power supply can be monitored externally using the monitor output connections on the Analog I O connector Each output is a buffered differential analog voltage representation of the signal being monitored The current monitor has a sensitivity of 7 V 70 A and the voltage monitor has a sensitivity of 3 5 V 35V Both outputs have a source impedance of 20 Q 3 10 COMPUTER INTERFACE The Model 642 can be programmed externally with a computer Both RS 232C and IEEE 488 ports are provide
69. RIPTION bite acc dee eae eee ec Se ee eee ei 1 1 1 2 SPECIFICATIONS 3 cui egene ets ail parece sD eae a alli 1 3 1 3 SAFETY dE 1 7 1 4 SAFETY SNMBOLS EE 1 9 2 MAGNET SYSTEM DESIGN INSTALLATION AND OPERATION ccc ccseseessseeeseeeeeeeesseeeeseeesseeeeseeeseeeeneeeenenees 2 1 2 0 EEN EE EE 2 1 2 1 INTRODUCTION venetian ena Re Arn a a iw i et 2 1 2 2 MAGNET CONSTRUCTION ccoo A ads 2 2 2 3 CONNECTING THE MAGNET nc nn nc rn nn nn nc 2 2 2 3 1 Water Hose Gonnection iisen ir dados 2 2 2 3 2 Magnet Coil WINNI EE 2 2 2 3 3 Temperature Switches and Flow Switches A 2 4 2 3 4 Cooling Water and Water Valve AA 2 4 2 3 5 EI eu EE 2 4 2 3 6 Final ei EE 2 5 2 4 ELECTROMAGNET OPERATION cn nan nn rn rn ran rn rn carr rn nn ra rnn rc nn ra nnnccnnnninss 2 5 2 4 1 AirGap and Pole EE 2 5 2 4 2 Maximum Power and Current unci n 2 5 2 4 3 Operation Under Field Control vc 3 agefugties ere N E eet cna dain chara betes 2 7 2 4 4 Avoiding Cooling Water Condensation ccceecceseeeeeeeeeeeeeeeeeeseeeeeeeeeesaeeeaeeesaeeeeeeeseeeeneeesiaeeneeeeaees 2 8 3 INSTALLATION aa 3 1 3 0 GENERAL oi 3 1 3 1 INSPECTION AND UNPAGKING ssie A os 3 1 3 1 1 Moving and Handling ita AA a eee e ee 3 1 3 2 REAR PANEL DEFINITION 50 accio ti dl da 3 2 3 3 POWER WIRING AND SET UPeicnian iaa cavities aaa aid cala 3 3 3 3 1 line Voltage Selectii nks rhii aan A EE ENEE ab tas 3 3 3 3 2 Circuit Ende DEE 3 4 3 3 3 SAUS ii 3 5 3 3 4 Cable E aaa ese 3 5 3 3 5 Power Input Te
70. Ramp Rate 99 999 A s External Program Mode External Program Mode Internal Ramp Segments Ramp Segment sses Disabled Ramp Segments Current 0 ee OA Ramp Segments Rate 1 0000 A s Display Bresson 25 Keypad Locking A O detent Unlocked Lock Code 123 Computer Interface Bd AA ca 9600 TEEE 488 Address 12 TEEE 488 Terminators ocooconinnnccncn CR LF Modera ie Local Water Settings Magnet Water Disabled Internal Water oooooonnnncccnnnonccinnnnoos Disabled Indicates value is also initialized on power up 4 12 Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual CHAPTER 5 COMPUTER INTERFACE OPERATION 5 0 GENERAL This chapter provides operational instructions for the computer interface for the Lake Shore Model 642 Electromagnet Power Supply Either of the two computer interfaces provided with the Model 642 permit remote operation The first is the IEEE 488 Interface described in Paragraph 5 1 The second is the Serial Interface described in Paragraph 5 2 The two interfaces share a common set of commands detailed in Paragraph 5 3 Only one interface can be used at a time 5 1 IEEE 488 INTERFACE The IEEE 488 Interface is an instrumentation bus with hardware and programming standards that simplify instrument interfacing The Model 642 IEEE 488 Interface complies with the IEEE 488 2 1987 standard and incorporates its functional electrical and mechanica
71. Set summary bit indicates that an enabled hardware error event has occurred Operational Errors Summary OESB Bit 1 Set summary bit indicates that an enabled operational error event has occurred From Operation Condition Register From Standard Event Status Register From Output Buffer From Error Status Register Hardware From Error Status Register Operational Status Byte 7 Goi be E RETO ECO RN Oe Hst Register a a STB Hess Joss za Name Generate service RQS request Reset by serial poll Service Request z e i DECH EC EC EC 50781 Enable Register Figure 5 6 Status Byte Register and Service Request Enable Register 5 12 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 4 4 2 Service Request Enable Register The Service Request Enable Register is programmed by the user and determines which summary bits of the Status Byte may set bit 6 RQS MSS to generate a Service Request Enable bits are logically ANDed with the corresponding summary bits see Figure 5 6 Whenever a summary bit is set by an event register and its corresponding enable bit is set by the user bit 6 will set to generate a service request The Service Request Enable command SRE programs the Service Request Enable Register and the query command SRE reads it Reading the Service Request Enable Register will not clear it The register m
72. The magnetic field produced by electromagnets is not linear with current setting The best way to compensate for this is to use closed loop field control but if absolute accuracy is not necessary than some of this nonlinearity can be corrected by the use of the ramp segments feature The ramp segments feature can be used to increase the current ramp rate as the magnet saturates in an attempt to maintain the same field ramp rate This feature can change the output current ramp rate based on the output current setting As the output setting ramps through the segment boundary the new ramp rate will be used although it will still be limited by the maximum ramp rate setting Refer to Paragraph 4 11 2 to set the maximum ramp rate To use the ramp segment feature the ramp segments must be enabled and the ramp segment table must be setup to specify which ramp rate to use for each current setting The table should be setup in order of increasing current A current entry of 0 A indicates the end of the table and the instrument will not search any higher in the table Operation 4 5 Lake Shore Model 642 Electromagnet Power Supply User s Manual Ramp Segments Continued To configure the ramp segments press Ramp Segments The first ramp segments setup screen appears as a prompt for the ramp segments mode Use the A or Y key to select the ramp segments mode either Enable or Disable Press Enter to accept the new selection and continue to
73. Troubleshooting New Installation 1 Check instrument Baud rate 2 Make sure transmit TD signal line from the instrument is routed to receive RD on the computer and vice versa Use a null modem adapter if not 3 Always send terminators 4 Send entire message string at one time including terminators Many terminal emulation programs do not 5 Send only one simple command at a time until communication is established 6 Be sure to spell commands correctly and use proper syntax Old Installation No Longer Working 7 Power instrument off then on again to see if it is a soft failure 8 Power computer off then on again to see if communication port is locked up 9 Verify that Baud rate has not been changed on the instrument during a memory reset 10 Check all cable connections Intermittent Lockups 11 Check cable connections and length 12 Increase delay between all commands to 100 ms to make sure instrument is not being over loaded Computer Interface Operation 5 27 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 3 COMMAND SUMMARY This paragraph provides a listing of the IEEE 488 and Serial Interface Commands A summary of all the commands is provided in Table 5 9 All the commands are detailed in Paragraph 5 3 1 which is presented in alphabetical order Sample Command Format SETI Output Current Setting Command Input Format Remarks Sample Query Format SETI lt current gt term
74. aai laine alee dicen 5 2 5 1 3 IEEE 488 Command Structure cities 5 2 5 1 3 1 Bus Control Gommands cia deta 5 3 5 1 3 2 Common GOMMANAS veto cicle Niet Shae eked a ee dite 5 3 5 1 3 3 Device Specific Commands i Seriate esaiar andaren cd alin dae ees 5 3 5 1 3 4 MeSSage Strings EE 5 3 5 1 4 Status System was Siva A ee 5 4 5 1 4 1 ICO hie O ied ee a ees 5 4 5 1 4 1 1 ue RE EE 5 4 5 1 4 1 2 Event Ke EC 5 4 5 1 4 1 3 Enable Registers netsted tl E 5 4 5 1 4 1 4 Status Byte e EE 5 4 5 1 4 1 5 Service Request Enable PHeglster AAA 5 4 5 1 4 1 6 Reading E EE 5 7 5 1 4 1 7 Programming SE LCE 5 7 5 1 4 1 8 Clearing WE EE 5 7 vi Table of Contents Lake Shore Model 642 Electromagnet Power Supply User s Manual TABLE OF CONTENTS Continued Chapter Section Title Page 5 1 4 2 Status Register Sets sich ie een a ies ee eee 5 8 5 1 4 2 1 Standard Event Status Register AAA 5 8 5 1 4 2 2 Operation Event Register Get 5 9 5 1 4 3 Error Status Register Selina aye hs sav Regal 5 10 5 1 4 3 1 Hardware Error Status Register Get 5 10 5 1 4 3 2 Operational Error Status Register Get 5 11 5 1 4 4 Status Byte and Service Request GO 5 12 5 1 4 4 1 ETC EE 5 12 5 1 4 4 2 Service Request Enable PHeglster AAA 5 13 5 1 4 4 3 Using Service Request SRQ and Serial Poll 5 13 5 1 4 4 4 Using Status Byte Query STE 5 13 5 1 4 4 5 Using Message Available MAV Dm 5 13 5 1 4 4 6 Using Operation Complete OPC and Operation Complete Query OPC P
75. aller start up power supply is fused separately and discussed in Section 7 5 If the breaker trips it will reset within a few minutes and the unit can be restarted If the unit trips again after a short time the circuit breaker trip current may be set incorrectly Table 7 1 shows required voltage and current settings Table 7 1 Voltage and Current Selection Nominal Voltage Voltage Tap Circuit Breaker 200 V 204 V 18A 208 V 204 V 18A 220 V 225 V 17A 230 V 225 V 17A 380 V 380 V 12A 400 V 408 V 12A 415 V 408 V 12A WARNING To avoid potentially lethal shocks turn off the power supply and disconnect it from AC power before performing this procedure CAUTION For continued protection against fire hazard use only the recommended current setting for the line voltage selected Use the following procedure to verify or change the circuit breaker current setting Identify the power wiring access panel on the rear of the Model 642 Turn the front panel line power switch OFF O Disconnect the power cable at the plug end for safety Remove the perimeter screws holding the power wiring access panel Refer to Figure 7 1 to locate the circuit breaker detailed in Figure 7 3 ON Be eee Lift the circuit breaker setting access door and visually confirm the setting as shown in Figure 7 3 Service 7 3 Lake Shore Model 642 Electromagnet Power Supply User s Manual O N zZ
76. am 5 26 5 9 Command Summary aisea Sidhe eee ieee oo ee etek 5 29 7 1 Voltage and Current Selection ssc s cincean a dt eee 7 3 7 2 Instrument Hardware Error Sissies pi aa a a aaa E a ea Ea A aaaea E te eiaa Aa SEERE aaa Taa 7 5 7 3 Operational o E A AT A A E ET 7 6 B 1 Conversion from CGS to SI Units coooccconccconccnonccnannnnnononannnnnnnc e E EE E E iea B 1 B 2 Recommended SI Values for Physical Constants no ncnrannnrancnrarr nr rnrrnn B 2 x Table of Contents Lake Shore Model 642 Electromagnet Power Supply User s Manual CHAPTER 1 INTRODUCTION 1 0 GENERAL This chapter provides an introduction to the Model 642 Electromagnet Power Supply The Model 642 was designed and manufactured in the United States of America by Lake Shore Cryotronics Inc The Model 642 features include the following e True 4 quadrant bipolar 70 A 35 V output 0 1 mA output setting resolution Linear regulation minimizes noise and ripple to 0 007 of maximum current into a 0 50 Q load e 1 0 mA stability per hour 5 mA per 24 hour e CE compliance to both the low voltage directive and the electromagnetic compatibility EMC directive 1 1 DESCRIPTION The Model 642 Electromagnet Power Supply is the ideal supply for small to medium sized magnets used in high sensitivity materials research applications The Model 642 is a practical alternative to both the larger one size fits all magnet supplies and the endless adaptations of generic power sup
77. ameter data gt lt terminators gt Command mnemonics and parameter data necessary for each one is described in Paragraph 5 3 Terminators must be sent with every message string Computer Interface Operation 5 3 Lake Shore Model 642 Electromagnet Power Supply User s Manual Message Strings Continued A query string is issued by the computer and instructs the instrument which response to send Queries are issued similar to commands with the computer acting as talker and the instrument as listener The query format is lt query mnemonic gt lt gt lt space gt lt parameter data gt lt terminators gt Query mnemonics are often the same as commands with the addition of a question mark Parameter data is often unnecessary when sending queries Query mnemonics and parameter data if necessary is described in Paragraph 5 3 Terminators must be sent with every message string Issuing a query does not initiate a response from the instrument A response string is sent by the instrument only when it is addressed as a talker and the computer becomes the listener The instrument will respond only to the last query it receives The response can be a reading value status report or the present value of a parameter Response data formats are listed along with the associated queries in Paragraph 5 3 5 1 4 Status System 5 1 4 1 Overview The Model 642 implements a status system compliant to the IEEE 488 2 1992 stand
78. amming Input The actual current output from this input is specified to a 1 tolerance and is not adjustable It is NOT necessary to engage the External Programming feature of the Model 642 for this calibration 1 Connect a new 9 V alkaline battery to the external current programming input lines positive to positive input 2 Send CALG 7 1 To set the external programming voltage reading gain constant to 1 3 Get the Model 642 external programming voltage reading and record V reading NOTE To get this reading from the Model 642 press and hold the Status key on the front panel until the display goes dark 3 seconds When the key is then released a diagnostics display will be seen The upper right reading Ext Prog is the reading needed for this step 4 Measure the voltage directly across the 9 V battery and record Vineasured 5 Calculate the gain constant per the following equation Programming Voltage Reading Gain Constant V measurea V reading 6 Verify the gain constant to be 1 0 05 7 Send CALG 7 constant 8 Verify the Model 642 external programming voltage reading to match the measured 9 V battery voltage within 0 0005 V 9 Send CALSAVE to write this calibration to non volatile memory 7 11 4 Calibration Specific Interface Commands The following interface commands are only used during calibration and are in addition to those listed in Chapter 5 CALG Gain Calibration Constant
79. an iron free solenoid in which the field is produced along the axis of the coil or an iron cored structure in which the field is produced in an air gap between pole faces The coil can be water cooled copper or aluminum or superconductive electrostatic discharge ESD A transfer of electrostatic charge between bodies at different electrostatic potentials caused by direct contact or induced by an electrostatic field error Any discrepancy between a computed observed or measured quantity and the true specified or theoretically correct value or condition excitation Either an AC or DC input to a sensor used to produce an output signal Common excitations include constant current constant voltage or constant power Fahrenheit F Scale A temperature scale that registers the freezing point of water as 32 F and the boiling point as 212 F under normal atmospheric pressure See Temperature for conversions feedback control system A system in which the value of some output quantity is controlled by feeding back the value of the controlled quantity and using it to manipulate an input quantity so as to bring the value of the controlled quantity closer to a desired value Also known as closed loop control system A 2 Glossary of Terminology Lake Shore Model 642 Electromagnet Power Supply User s Manual four lead measurement technique where one pair of excitation leads and an independent pair of measurement leads are used to me
80. ard The status system provides a method of recording and reporting instrument information and is typically used to control the Service Request SRQ interrupt line A diagram of the status system is shown in Figure 5 1 The status system is made up of register sets the Status Byte register and the Service Request Enable register Each register set consists of three types of registers condition event and enable 5 1 4 1 1 Condition Registers Each register set except the Standard Event Register set includes a condition register as shown in Figure 5 1 The condition register constantly monitors the instrument status The data bits are real time and are not latched or buffered The register is read only 5 1 4 1 2 Event Registers Each register set includes an event register as shown in Figure 5 1 Bits in the event 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 cleared by a query command such as ESR or a CLS command The register is read only 5 1 4 1 3 Enable Registers Each register set includes an enable register as shown in Figure 5 1 An enable register determines which bits in the corresponding event register 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
81. ary is described in Paragraph 5 3 Terminators must be sent with every message string The computer should expect a response very soon after a query is sent A response string is the instruments response or answer to a query string The instrument will respond to the last query or queries it receives The response can be a reading value status report or the present value of a parameter Response data formats are listed along with the associated queries in Paragraph 5 3 The response is sent as soon as possible after the instrument receives the query Typically it takes 10 ms for the instrument to begin the response Some responses take longer 5 2 6 Message Flow Control It is important to remember that the user program is in charge of the serial communication at all times The instrument cannot initiate communication determine which device should be transmitting at 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 e Properly format and transmit the command including terminators as one string e 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 issuing queries or queries and commands together the user program should e Properly format and transmit the query including terminators as one string e Prepare to receive a resp
82. asure a sensor This method reduces the effect of lead resistance on the measurement gamma A cgs unit of low level flux density where 100 000 gamma equals one oersted or 1 gamma equals 10 oersted gauss G The cgs unit for magnetic flux density B 1 gauss 10 tesla Named for Karl Fredrich Gauss 1777 1855 a German mathematician astronomer and physicist gaussian system units A system in which centimeter gram second units are used for electric and magnetic qualities general purpose interface bus GPIB Another term for the IEEE 488 bus germanium Ge A common temperature sensing material fabricated from doped germanium to make the Lake Shore GR family of resistance temperature sensor elements gilbert Gb A cgs electromagnetic unit of the magnetomotive force required to produce one maxwell of magnetic flux in a magnetic circuit of unit reluctance One gilbert is equal to 10 4m ampere turn Named for William Gilbert 1540 1603 an English physicist hypothesized that the Earth is a magnet gilbert per centimeter Practical cgs unit of magnet intensity Gilberts per cm are the same as oersteds Greek alphabet The Greek alphabet is defined as follows Alpha a A Iota 1 I Rho p P Beta B B Kappa K K Sigma o x Gamma Y T Lambda A A Tau T T Delta A Mu u M Upsilon v Y Epsilon D E Nu v N Phi o KU Zeta E Z Xi E Chi H X Eta n H Omicron o O Psi y Y Theta 0 Pi T Il Omega o Q ground A conducting connection whether intentio
83. at Operational Status Query OPST term lt bit weighting gt term nnn The integer returned represents the sum of the bit weighting of the operational status bits Refer to Paragraph 5 1 4 2 2 for a list of operational status bits Operational Status Enable Command OPSTE lt bit weighting gt term nnn Each bit has a bit weighting and represents the enable disable mask of the corresponding operational status 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 5 1 4 2 2 for a list of operational status bits Operational Status Enable Query OPSTE term lt bit weighting gt term nnn Refer to Paragraph 5 1 4 2 2 for a list of operational status bits Operational Status Register Query OPSTR term lt bit weighting gt term nnn The integers returned represent the sum of the bit weighting of the operational status bits These status bits are latched when the condition is detected This register is cleared when it is read Refer to Paragraph 5 1 4 2 2 for a list of operational status bits Output Current Ramp Rate Setting Command RATE lt rate gt term n nnnn lt rate gt Specifies the rate at which the current will ramp at when a new output current setting is entered 0 0001 99 999 A s Sets the ou
84. ata entry keys that are printed on the key tops Data entry keys include numbers from 0 to 9 sign and decimal point The labels printed above the keys describe the key function during normal operation When one of the keys is pressed and a data entry sequence is started the keys follow the data entry functions printed on the key tops Once the correct parameter value is entered press Enter to accept the change and advance 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 a value for Related setting selection and data entry sequences are often chained together under a single key To skip over a parameter without changing its value press Enter before pressing an arrow or number key To return to the normal display in the middle of a setting sequence press Escape before pressing an arrow or number key Changes entered before Escape is pressed are kept 4 5 DISPLAY SETUP The Display Setup allows the user to set the display brightness The vacuum fluorescent VF display on the Model 642 has four brightness settings between 25 and 100 that can be changed from the front panel The brightness setting changes the entire VF display but does not affect the LED annunciators to the right of the display Continuous use of the instrument at 100 brightness will reduce the operating life of the
85. aterial parameter which is the ratio of the magnetic induction B to the magnetic field strength H u B H Also see Initial Permeability and Differential Permeability platinum Pt A common temperature sensing material fabricated from pure platinum to make the Lake Shore PT family of resistance temperature sensor elements polynomial fit A mathematical equation used to fit calibration data Polynomials are constructed of finite sums of terms of the form aixi where a is the i fit coefficient and x is some function of the dependent variable positive temperature coefficient PTC Refers to the sign of the temperature sensitivity For example the resistance of a PTC sensor increases with increasing temperature pounds per square inch psi A unit of pressure 1 psi 6 89473 kPa Variations include psi absolute psia measured relative to vacuum zero pressure where one atmosphere pressure equals 14 696 psia and psi gauge psig where gauge measured relative to atmospheric or some other reference pressure ppm Parts per million e g 4x 10 is four parts per million precision Careful measurement under controlled conditions which can be repeated with similar results See repeatability Also means that small differences can be detected and measured with confidence See resolution prefixes SI prefixes used throughout this manual are as follows Factor Prefix Symbol Factor Prefix Symbol 10 yotta Y 107 deci d 107 zet
86. ay be cleared by the user by sending SRE 0 5 1 4 4 3 Using Service Request SRQ and Serial Poll When a Status Byte summary 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 will automatically clear RQS of the Status Byte Register This allows subsequent serial polls to monitor bit 6 for an SRQ occurrence generated by other event types After a serial poll the same event or any event that uses the same Status Byte summary bit will not cause another SRQ unless the event register that caused the first SRQ has been cleared typically by a query of the event register The serial poll does not clear MSS The MSS bit stays set until all enabled Status Byte summary bits are cleared typically by a query of the associated event register refer to Paragraph 5 1 4 4 4 The programming example in Table 5 3 initiates an SRQ when a command error is detected by the instrument Table 5 3 Programming Example to Generate an SRQ Command or Operation Description ESR Read and clear the Standard Event Status Register ESE 32 Enable the Command Error CME bit in the Standard Event Status R
87. bas b Vbib 32 bas NOTE If the files in Steps 2 and 3 are not installed on your computer they may be copied from your National Instruments setup disks or they may be downloaded from www ni com 4 Configure the GPIB by selecting the System icon in the Windows Control Panel located under Settings on the Start Menu Configure the GPIB Settings as shown in Figure 5 7 Configure the DEV12 Device Template as shown in Figure 5 8 Be sure to check the Readdress box 5 14 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual System Properties 1x General Device Manager Hardware Profiles Perform MAN ES IS HE General GPIB Settings Resources View devices by type View devices by col m Computer y AT GPIB TNT Plug and Play amp CDROM H E Disk drives MISA PnP Serial Number 004D7F 40 E a Display adapters 2 2 Floppy disk controllers Interface Name m Termination Methods Hard disk controllers GPIB y IV Send EOI at end of Write H E Keyboard 7 2 Monitor GPIB Address MV Terminate Read on EOS H A Mouse i P P E y National Instruments GPIB Interfaces Ga EE AT GPIB TNT Plug and Play FT 8 bit EOS Compare D 7 Network adapters Secondary 2 4 Ports COM amp LPT 10 EOS Byte o BR System devices NONE Z m si 140 Timeout 10sec y Properties Refresh Remove IV System Controller OK
88. c bags approved for storage of ESD material 6 Do not handle ESDS devices unnecessarily or remove from the packages until actually used or tested 7 8 ENCLOSURE TOP PANEL REMOVAL AND REPLACEMENT WARNING To avoid potentially lethal shocks set current output to 0 A turn off the power supply and disconnect it from AC power line before performing this procedure Only qualified personnel should perform this procedure 7 8 1 Removal 1 Set power switch to Off O and disconnect power cord from the power outlet 2 Remove the Model 642 from rack if necessary to gain easy access to the top panel 3 Remove and retain the 17 flat head Phillips screws securing the top panel of the Model 642 4 Remove and retain the two truss head Phillips screws and nylon washers from the top edge of the front panel that secure the top panel to the front panel 5 Carefully remove the top panel from the unit 7 8 2 Installation 1 Replace the top panel on the Model 642 with the folded lip of the panel toward the front of the unit 2 Replace and secure the 17 flat headed Phillips screws Do not use excessive torque 3 Replace the two Phillips head screws securing the top panel lip to the top edge of the front panel 4 Replace the Model 642 in the rack if used 5 Reconnect the Model 642 to the power outlet Apply power via the front panel button I 7 9 FIRMWARE REPLACEMENT There are two integrated circuits IC that may potentially require replacem
89. 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 summary bit of the Status Byte register 5 1 4 1 4 Status Byte Register The Status Byte register typically referred to as simply the Status Byte is a non latching read only register that contains all of the summary bits from the register sets The status of the summary bits are controlled from the register sets as explained above The Status Byte also contains the Request for Service RQS Master Summary Status MSS bit This bit is used to control the Service Request hardware line on the bus and to report if any of the summary bits are set via the STB command The status of the RQS MSS bit is controlled by the summary bits and the Service Request Enable Register 5 1 4 1 5 Service Request Enable Register The Service Request Enable Register determines which summary bits in the Status Byte will set the RQS MSS bit of the Status Byte The user may write to or read from the Service Request Enable Register Each Status Byte summary bit is logically ANDed to the corresponding enable bit of the Service Request Enable Register When a Service Request Enable Register bit is set by the user and the corresponding summary bit is set in the Status Byte the RQS MSS bit of the Status Byte will be set which in turn sets the Service Reque
90. d 3 10 1 RS 232C Interface Connection An RS 232C port has been provided to allow remote computer control of the power supply Refer to Chapter 5 Computer Interface Operation 3 10 2 IEEE 488 Interface Connection An IEEE 488 port has been provided to allow remote computer control of the power supply Refer to Chapter 5 Computer Interface Operation 3 11 CHASSIS CONNECTION A 6 32 screw has been provided for attaching an optional chassis ground connection This connection is normally not required However occasionally there are noise problems associated with a floating magnet or other ancillary equipment Installation 3 11 Lake Shore Model 642 Electromagnet Power Supply User s Manual 3 12 DETACHABLE HANDLES The Model 642 is supplied with 4 detachable handles to enable handling The handles should normally remain attached to the unit However in some cases it may be necessary to remove the handles to enable mounting in an equipment rack In this case handles may be removed but they should be stored in the rack with the power supply so that they may be reattached if the unit must be returned for service Heavy duty handles have been installed to carry the weight of the power supply No substitutions should be made Light duty handles may fail when moving the supply causing the risk of injury to personnel and damage to equipment 3 13 RACK MOUNTING The Model 642 can be installed in a standard 19 inch rack mount cabinet and
91. d pair with NDAC 21 GND9 Ground Wire Twisted pair with IFC 22 GND10 Ground Wire Twisted pair with SRQ 23 GND 11 Ground Wire Twisted pair with ATN 24 GND Logic Ground Figure 7 12 IEEE 488 Connector Details Service Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 11 CALIBRATION Lake Shore maintains a fully automated calibration fixture for the Model 642 that measures existing performance of the unit and then recalibrates the using NIST traceable resistance and voltage standards In addition non calibration features are verified for proper operation by a full battery of extensive tests Although this testing is very complete it requires the return of the Model 642 to Lake Shore to perform the recalibration In some instances however it may be necessary to recalibrate the Model 642 in the field Calibration information for the following operating parameters is provided Output Current Output Current Reading e Output Voltage Reading e External Programming Voltage Reading These calibrations are done through the computer interface and the calibration constants are stored in the non volatile memory in the instrument The cover does not have to be removed to calibrate the instrument The remaining features of the Model 642 do not require calibration to operate within their specified tolerances Uncalibrated default values for gains are 1 while offsets are 0 Operation w
92. d primary addresses range Type of compare on EOS i from 0 to 30 00H to 1EH Send EOI at end of Write Adding 32 to the primary address forms the Listen Address LA Enable Repeat Addressing Adding 64 to the primary address forms the Talk Address TA EXAMPLE Selecting a primary address of 10 yields the following 10 32 42 Listen address 10 64 74 Talk address Fl Help F6 Reset Value F9 Esc Return to Map Ctl PgUp PgDn Next Prev Board IBCONF EXE eps Figure 5 9 Typical National Instruments GPIB Configuration from IBCONF EXE Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 5 3 Program Operation Once the running try the following commands and observe the response of the instrument Input from the user is shown in bold and terminators are added by the program The word term indicates the required terminators included with the response ENTER COMMAND IDN Identification query Instrument will return a string identifying itself RESPONSE LSCI MODELModel 642 1234567 06122006 term ENTER COMMAND SETI Output current setting query Instrument will return a string with the present output current setting RESPONSE 20 0545 term ENTER COMMAND XPGM 0 External program mode command Instrument will set program mode to internal No response will be sent ENTER COMMAND XPGM External program mode query Instrument will return a string wit
93. das 6 1 6 2 ACGESSORIES AVAILABLE EE 6 1 Te SERVICE adonde 7 1 7 0 EIS EE 7 1 7 1 CONTACTING LAKE SHORE CRYOTRONICS A 7 1 7 2 RETURNING PRODUCTS TO LAKE SHORE AA 7 1 7 3 LINE VOLTAGE SELECTION scuste0 ci ite orrei esor E a esras edd 7 2 7 4 CIRCUIT BREAKER SETTING iiicce cece naib eters en eee 7 3 7 5 POWER LINE FUSE REPLAGEMENT detresse dE deed E ative ete cetyl ed 7 4 7 6 ERROR MESSAGE S ger seet fester AE a ia a aia 7 5 7 7 ELECTROSTATIC DISCHARGE cot ea doe a ete dio alin 7 6 7 7 1 Identification of Electrostatic Discharge Sensitive Components ooooooncccncccnnccconcnconcnonnnnnancnnannncancnnnna 7 6 7 7 2 Handling Electrostatic Discharge Sensitive COMPONENTS oooooocncccnnccccoccconnnoncconnnnnancncnnnnnancnnannnnancnnnns 7 7 7 8 ENCLOSURE BOTTOM REMOVAL AND REPLACEMENT A 7 7 7 8 1 MOV WEE 7 7 7 8 2 UC HE e ieee AA ee ee A 7 7 Table of Contents vil Lake Shore Model 642 Electromagnet Power Supply User s Manual TABLE OF CONTENTS Continued Chapter Section Title Page 7 9 FIRMWARE REPLACEMENT seo Geine aetta see arenes Geers eaten are era tented 7 7 7 10 CONNECTOR AND CABLE DEFINITIONS A 7 11 7 10 1 Analog VO Conn eC OT cscs EE 7 11 7 10 2 Magnet Connector racinas NENNEN ee 7 11 7 10 3 Auxiliary nl e EE 7 12 7 10 4 Power Supply Conector micosis a age 7 13 7 10 5 RS 232C Serial Interface Connector oooconcconoccconcccnnncconcnonnnncononcnnonnanc nro cnn nc rra nc 7 13 7 10 6 Serial Interface Cable Wir a
94. data entry operations These displays are illustrated in their individual operation paragraphs A typical display is shown below A3 LED ANNUNCIATORS There are five LED annunciators on the front panel that are used to indicate the status of the instrument These provide easy verification of the operation of the instrument See Figure 4 2 for LED locations Table 4 1 Model 642 LED Descriptions Fault On when a hardware fault condition exists blinking when a soft fault condition exists Compliance On when maximum compliance voltage is reached Power Limit On when power in internal devices reaches the maximum limit Ramping On when output current is ramping blinking when ramp is paused Remote On when instrument is in remote computer interface mode 4 3 1 Fault LED The Fault LED will light whenever an error condition is encountered It may also be accompanied by an alarm depending on the fault Refer to Table 7 2 Instrument Hardware Errors and Table 7 3 Operational Errors 4 3 2 Compliance LED The Compliance LED lights whenever the maximum output voltage is reached This can happen when attempting to rapidly ramp a magnet with higher than usual voltage required to overcome the magnet s inductance The led will go out when the condition clears 4 3 3 Power Limit LED The Model 642 has a hardware power limit to protect the internal power MOSFETs If the power supply is driving a load which has a
95. dure to develop the Serial Interface Program in Visual Basic Start VB6 Choose Standard EXE and select Open Resize form window to desired size On the Project Menu click Components to bring up a list of additional controls available in VB6 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 1 2 3 4 Er 6 7 a b c d Select the Comm control and add it to the form Add controls to form Add three Label controls to the form Add two TextBox controls to the form Add one CommandButton control to the form Add one Timer control to the form 8 On the View Menu select Properties Window 9 In the Properties window use the dropdown list to select between the different controls of the current project Label1 Command1 ia Serial Interface Program Label3 Label2 10 Set the properties of the controls as defined in Table 5 7 11 Save the program 5 24 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual Table 5 7 Serial Interface Program Control Properties Current Name Property New Value Label Name IbIExitProgram Caption Type exit to end program Label2 Name IblCommand Caption Command Label3 Name IblResponse Caption Response Textl Name txtCommand Text lt blank
96. e instrument Return the instrument to an authorized Lake Shore representative for service to ensure that safety features are maintained Prevent Cooling Water Condensation Do not operate the power supply when cooling water temperature is at or lower than the dew point for local atmospheric conditions Condensation on cooling water lines inside the power supply can cause severe damage Refer to Section 2 4 4 for additional details Cleaning Do not submerge instrument Clean only with a damp cloth and mild detergent on exterior surfaces only Moving and Handling Four handles are provided for ease of moving and handling the Model 642 The handles can be used in place of lifting lugs when cloth straps are used Always use all four handles when moving the unit Because of its weight the Model 642 should be handled by mechanical means If for some reason it is necessary to move it by hand a minimum of two people is required CAUTION To avoid injury to personnel always observe proper lifting techniques in accordance with OSHA and other regulatory agencies 1 8 Introduction Lake Shore Model 642 Electromagnet Power Supply User s Manual Safety Summary Continued 1 4 SAFETY SYMBOLS Number 1 10 11 12 13 14 15 16 None Symbol Ny x 37N ZV gt oO O AE Publication IEC 417 No 5031 IEC 417 NO 5032 IEC 417 No 5033 IEC 617 2 No 02 02 06 IEC 417 No 5017 IEC 417 No
97. ection Continued Changing line voltage is accomplished by moving four wires to the required voltage terminals The required location is shown in Figure 3 2 To change the voltage setting loosen the four terminal screws in the voltage change terminal block to which the wires are connected and move the wires to the required voltage position The wires are held in place ina locator card to maintain their spacing and prevent mis wiring The screws in the new terminal location must be loosened four full turns to allow the entry of the wires Move all four wires at once by lifting the locator card to extract the wires from the terminals Move the card and wires to the correct location and insert the wires completely so that the card rests against the terminals While holding the locator card in place to keep the wires fully inserted tighten the terminal screws The recommended torque requirement is 0 5 Nm Also tighten the four terminals where the wires were previously VOLTAGE SELECTOR CARD VOLTAGE INDICATOR KEY AAA E JF a WIRE FERRULE i i egeee2egegeegede TERMINAL SCREW z ado codo Ww AAS Figure 3 2 Voltage Change Detail 3 3 2 Circuit Breaker Setting The circuit breaker is an important safety feature of the Model 642 The required current setting depends on the voltage for which the unit is wired Refer to Table 3 2 Verify that the circuit breaker is set correctly for the line voltage being applied to the unit
98. ed one bit at a time rather than one byte character at a time as in a parallel interface RS 232C is the most common serial interface SI Systeme International d Unit s See International System of Units stability The ability of an instrument or sensor to maintain a constant output given a constant input strain relief A predetermined amount of slack to relieve tension in component or lead wires Also called stress relief susceptance In electrical terms susceptance is defined as the reciprocal of reactance and the imaginary part of the complex representation of admittance suscept ibility conduct ance susceptibility x Parameter giving an indication of the response of a material to an applied magnetic field The susceptibility is the ratio of the magnetization M to the applied field H x M H In both SI units and cgs units the volume susceptibility is a dimensionless parameter Multiply the cgs susceptibility by 47 to yield the SI susceptibility See also Initial Susceptibility and Differential Susceptibility As in the case of magnetization the susceptibility is often seen expressed as a mass susceptibility or a molar susceptibility depending upon how M is expressed temperature scales See Kelvin Scale Celsius Scale and ITS 90 Proper metric usage requires that only Kelvin and degrees Celsius be used However since degrees Fahrenheit is in such common use all three scales are delineated as follows Boiling point of water
99. egister SRE 32 Enable the Event Summary Bit ESB to set the RQS ABC Send improper command to instrument to generate a command error Monitor bus Monitor the bus until the Service Request interrupt SRQ is sent Serial Poll the bus to determine which instrument sent the interrupt and clear the RQS bit Initiate Serial Poll in the Status Byte Read and clear the Standard Event Status Register allowing an SRQ to be generated on ESR 8 another command error 5 1 4 4 4 Using Status Byte Query STB The Status Byte Query STB command is similar to a Serial Poll except it is processed like any other instrument command The STB command returns the same result as a Serial Poll except that the Status Byte bit 6 RQS MSS is not cleared In this case bit 6 is considered the MSS bit Using the STB command does not clear any bits in the Status Byte Register 5 1 4 4 5 Using Message Available MAV Bit Status Byte summary bit 4 MAV indicates that data is available to read into your bus controller This message may be used to synchronize information exchange with the bus controller The bus controller can for example send a query command to the Model 642 and then wait for MAV to set If the MAV bit has been enabled to initiate an SRQ the user s program can direct 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 Computer Inter
100. eighting gt term Format nnn Refer to command for description ESR Standard Event Status Register Query Input ESR term Returned lt bit weighting gt 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 CLS command Refer to Paragraph 5 1 4 2 1 IDN Identification Query Input IDN term Returned lt manufacturer gt lt model gt lt serial gt lt firmware version gt term Format aaaa aaaaaaaa aaaaaaa n n n n lt manufacture gt Manufacturer ID lt model gt Instrument model number lt serial gt Serial number lt firmware version gt Instrument firmware version main firmware DAC firmware Example LSCI MODEL642 1234567 1 0 1 0 OPC Operation Complete Command Input OPC term Remarks Used in conjunction with bit 0 OPC of the Standard Event Status Register If sent as the last command in a command sequence bit 0 will be set when the instrument completes the operation that was initiated by the command sequence Refer to Paragraph 5 1 4 4 6 for more information OPC Operation Complete Query Input OPC term Returned 1 term Remarks Has no interaction with bit 0 OPC of the Standard Event Status Register If sent at the end of a command sequence the bus will be held until the instrument comple
101. en the programming voltage is less than 0 025 V or the instrument is changed to internal current programming mode Calibration Invalid The instrument has either not been calibrated or calibration data has been corrupted This error can be cleared at any time by pressing both ESC and ENTER keys on the keypad simultaneously The instrument can still be used in this state but there is no guarantee that it is operating within specifications The instrument must be recalibrated to properly correct this error condition 7 7 ELECTROSTATIC DISCHARGE Electrostatic Discharge ESD may damage electronic parts assemblies and equipment ESD is a transfer of electrostatic charge between bodies at different electrostatic potentials caused by direct contact or induced by an electrostatic field The low energy source that most commonly destroys Electrostatic Discharge Sensitive ESDS devices is the human body which generates and retains static electricity Simply walking across a carpet in low humidity may generate up to 35 000 volts of static electricity Current technology trends toward greater complexity increased packaging density and thinner dielectrics between active elements which results in electronic devices with even more ESD sensitivity Some electronic parts are more ESDS than others ESD levels of only a few hundred volts may damage electronic components such as semiconductors thick and thin film resistors and piezoelectric cr
102. ent See Figure 7 6 for respective locations e Main Firmware Erasable Programmable Read Only Memory EPROM U35 Contains the user interface software Has a sticker on top labeled MModel 642F HEX and a date e DAC Microcontroller U51 Contains software that controls the output DAC Has a sticker on top labeled MModel 642DACF HEX and a date Use the following procedure to replace either or both of these ICs 1 Follow the top of enclosure removal procedure of Section 7 8 1 2 Refer to Figure 7 5 and locate the Digital Board assembly 3 Disconnect the housekeeping transformer connector from J 1 Service 1A Lake Shore Model 642 Electromagnet Power Supply User s Manual Firmware Replacement Continued 4 Disconnect the ribbon cable to the Analog Board assembly from J 2 Disconnect the cable to the fan from J 3 Disconnect the ribbon cable to the Keypad Board assembly from J 4 Disconnect the main transformer connector from J 7 e A E Remove all connections from the IEEE 488 RS232C Power Supply Auxiliary and Magnet Water connectors on the back of the Model 642 9 Remove and retain the hexagonal mounting standoffs from the IEEE 488 and RS232C connectors on the back of the Model 642 10 Locate remove and retain the two 6 32 pan head machine screws holding the Digital Board in place See Figure 7 6 11 Remove the Digital Board by pulling it toward the front to clear the rear connectors from t
103. er or fuse The rating of the protection device shall be a value equal to that of the internal breaker or the next higher commercially available value See Table 3 2 If the Model 642 is connected with permanent wiring a disconnect switch shall be installed The disconnect switch shall be located within 3 meters 10 feet of the Model 642 be clearly marked in layman s language and be easily accessible 3 4 MAGNET CONNECTOR The magnet connector provides terminals for an optional magnet temperature switch or magnet water flow switch and an optional magnet water control solenoid valve The flow or temperature switch must have a normally closed contact rated at 5 V at 10 mA A contact closure is required to enable the Model 642 output If a switch is not used a jumper is required 24 VAC at 1 A is provided to operate a solenoid water valve for the magnet This output is controlled by the power supply either automatically via software or manually through the Magnet Water menu Water control is desirable to reduce water consumption when the water comes from a municipal facility Turning the water off when it is not required also reduces the probability of condensation on the magnet or connecting hoses If the cooling water comes from a facility chiller system condensation is not usually a problem and a control valve is not required In this case it is appropriate to install a flow switch optional or temperature switch optional to monitor the water
104. erface Operation 5 9 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 4 3 Error Status Register Sets As shown in Figure 5 1 there are two register sets in the error status system of the Model 642 Hardware Error Status Register and Operational Error Status Register 5 1 4 3 1 Hardware Error Status Register Set The Hardware Error Status Register reports the following instrument hardware error events temperature fault output over voltage output over current DAC processor not responding and output control failure Any or all of these events may be reported in the standard event summary bit through the enable register see Figure 5 4 The Hardware Error Status Register is the first value of the two values associated with the Error Status Registers The Error Status Enable command ERSTE programs the enable register and the query command ERSTE reads it ERSTR reads and clears the Error Status Register The used bits of the Error Status Event Register are described as follows Temperature Fault TF Bit 4 This bit is set if the internal temperature of the instrument exceeded the maximum safe value of 45 C The instrument will shut down within 10 seconds of detecting this fault Output Over Voltage OOV Bit 3 This bit is set if the output voltage exceeded the compliance voltage limit setting Output Over Current OOC Bit 2 This bit is set if the output current is above 62 A exceeding the maximu
105. esirable effects in circuits of control systems in which they occur normalized sensitivity For resistors signal sensitivity dR dT is geometry dependent i e dR dT scales directly with R consequently very often this sensitivity is normalized by dividing by the measured resistance to give a sensitivity sr in percent change per Kelvin sp 100 R dR dT K where T is the temp in Kelvin and R is the resistance in ohms normally closed N C A term used for switches and relay contacts Provides a closed circuit when actuator is in the free unenergized position normally open N O A term used for switches and relay contacts Provides an open circuit when actuator is in the free unenergized position oersted Oe The cgs unit for the magnetic field strength H 1 oersted 10 47 ampere meter 79 58 ampere meter ohm Q The SI unit of resistance and of impedance The ohm is the resistance of a conductor such that a constant current of one ampere in it produces a voltage of one volt between its ends open loop A control system in which the system outputs are controlled by system inputs only and no account is taken of actual system output pascal Pa The SI unit of pressure equal to 1 N m Equal to 1 45 x 10 psi 1 0197 x 10 kgr cm 7 5 x 107 torr 4 191 x 10 inches of water or 1 x 107 bar A 4 Glossary of Terminology Lake Shore Model 642 Electromagnet Power Supply User s Manual permeability M
106. etic induction B in a magnetic material to zero coercivity generally used to designate the magnetic field strength H required to reduce the magnetic induction B in a magnetic material to zero from saturation The coercivity would be the upper limit to the coercive force cryotronics The branch of electronics that deals with the design construction and use of cryogenic devices Curie temperature Tc Temperature at which a magnetized sample is completely demagnetized due to thermal agitation Named for Pierre Curie 1859 1906 a French chemist current source A type of power supply that supplies a constant current through a variable load resistance by automatically varying its compliance voltage A single specification given as compliance voltage means the output current is within specification when the compliance voltage is between zero and the specified voltage curve A set of data that defines the temperature response of a temperature sensor It is used to convert the signal from the sensor to temperature demagnetization when a sample is exposed to an applied field H poles are induced on the surface of the sample Some of the returned flux from these poles is inside of the sample This returned flux tends to decrease the net magnetic field strength internal to the sample yielding a true internal field Hine given by Hin Ha DM where M is the volume magnetization and D is the demagnetization factor D is dependent
107. f more instruments or cable length is required a bus expander must be used Computer Interface Operation 5 1 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 1 Changing IEEE 488 Interface Parameters Two interface parameters address and terminators must be set from the front panel before communication with the instrument can be established Other interface parameters can be set via the interface using the device specific commands provided in Paragraph 5 3 To set the IEEE 488 parameters press the Computer Interface key and press Enter to skip past Serial Interface Baud Rate The following computer interface screen appears as a prompt for the IEEE 488 address Use the A or Y key to select an address between 1 and 30 The default is twelve 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 computer interface screen appears as a prompt for the IEEE 488 terminators Use the A or Y key to select one of the following terminators CR LF LF CR LF and EOI The default is Cr Lf 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 5 1 2 Remote Local Operation Normal operations from the keypad are referred to as Local operations The Model 642 can also be configured for
108. f of the appropriate type and size must be provided by the installing agency CAUTION Failure to install a strain relief bushing is a hazard and could cause injury or death to operating personnel in the event of a fault Lake Shore reserves the right to void the warranty of any instrument not properly installed A typical cable entry with bushing is shown in Figure 3 5 CABLE COMPRESSION COLLAR CONDUIT BUSHING SLIP WASHER LOCKING RING COMPRESSION GROMMET 642 REAR PANEL BUSHING BODY Figure 3 5 Typical Cable Entry with Bushing 3 3 5 Power Input Terminals The Model 642 requires a 4 conductor power cord not included The input to the Model 642 is wired in a delta configuration but will operate from a delta or wye source If operating from a wye source the neutral line N is not used The ground the green yellow ground terminal connects the instrument chassis to the electrical ground safety ground and is required to prevent fault conditions which may be hazardous to operating personnel In no case should the safety ground line be omitted In no case should a neutral line be used as a safety ground If a detachable cord is used always plug the power cord into a properly grounded receptacle to ensure safe operation of the instrument All wiring must comply with the code requirements of the locality in which the instrument is installed Figure 3 6 shows typical input wiring The wire ferrules shown are not required but are recommended
109. f the instrument Input from the user is shown in bold and terminators are added by the program The word term indicates the required terminators included with the response ENTER COMMAND IDN Identification query Instrument will return a string identifying itself RESPONSE LSCI MODELModel 642 1234567 06122006 term ENTER COMMAND SETI Output current setting query Instrument will return a string with the present output current setting RESPONSE 20 0545 term ENTER COMMAND XPGM 0 External program mode command Instrument will set program mode to internal No response will be sent ENTER COMMAND XPGM External program mode query Instrument will return a string with the present external program mode setting RESPONSE 0 term ENTER COMMAND XPGM 1 XPGM External program mode command followed by a query Instrument will change to external programming mode then return a string RESPONSE 1 term with the present setting The following are additional notes on using either IEEE 488 Interface program e Ifyou 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 e 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 5 2 8
110. face Operation 5 13 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 4 4 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 OPC command is used in conjunction with bit 0 OPC of the Standard Event Status Register If OPC is sent as the last command in a command sequence bit 0 will be set when the instrument completes the operation that was initiated by the command sequence Additional commands may be sent between the instrument and the bus controller while waiting for the initial pending operation to complete A typical use of this function would be to enable the OPC bit to generate an SRQ and include the OPC command when programming the instrument The bus controller could then be instructed to look for an SRQ allowing additional communication with the instrument while the initial process executes The OPC query has no interaction with bit 0 OPC of the Standard Event Status Register If the OPC query is sent at the end of a command sequence the bus will be held until the instrument completes the operation that was initiated by the command sequence Additional commands except RST should not be sent until the operation is complete as erratic operation will occur Once the sequence is complete a 1 will be
111. ficate CAL 642 DATA Instrument recalibration with certificate and data 1 3 SAFETY SUMMARY Observe these safety precautions during all phases of instrument operation service and repair Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design manufacture and intended instrument use Lake Shore assumes no liability for Customer failure to comply with these requirements The Model 642 protects the operator and surrounding area from electric shock or burn mechanical hazards excessive temperature and spread of fire from the instrument Environmental conditions outside of the conditions below may pose a hazard to the operator and surrounding area e Indoor use e Maximum relative humidity 80 for temperature up to e Altitude to 2000 meters 31 C decreasing linearly to 50 at 40 C e Temperature for safe operation 5 C to 40 C e Power supply voltage fluctuations not to exceed 10 Over voltage category II of the nominal voltage e Pollution degree 2 Power and Ground Connections This instrument must be connected to a dedicated three phase power circuit with proper size of circuit breaker Refer to Chapter 3 Installation Verify that the unit has been configured for the correct input voltage The neutral line if available is not used The unit may be hard wired or connected with a flexible cable and plug In all cases the correct size wire must be cho
112. flow and protect the magnet in the event of a water flow interruption Figure 3 8 shows examples of typical magnet connector wiring FLOW FLOW dn FLOW FLOW SWITCH SWITCH J a SWITCH SWITCH WATER WATER Jr E WATER WATER _ gt S VALVE VALVE E o VALVE VALVE NO VALVE OR SWITCH VALVE ONLY SWITCH ONLY VALVE AND SWITCH Figure 3 8 Typical Magnet Connector Wiring 3 5 AUXILIARY CONNECTOR The Auxiliary connector provides terminals for an emergency stop contacts for a remote alarm remote enable and a chassis connection The Emergency Stop must have a normally closed contact rated at 24 V at 1 A When the contact is opened it turns off the Model 642 If an Emergency Stop switch is not used a jumper is required A normally closed or normally open contact is provided to control a remote alarm annunciator This set of contacts is rated at 30 V 1 A If it is desirable to have a remotely located alarm to echo the internal alarm these contacts can be used with an external power source and external alarm The Remote Enable switch must have a normally closed contact rated at 5 V at 10 mA contact closure is required to enable the Model 642 output If a remote enable switch is not used a jumper is required Figure 3 8 shows some typical auxiliary connector wiring A chassis terminal is provided in the event that any of the wires require a shield to minimize noise Figure 3 9 shows some typical Auxiliary Connector wiring EMERGENCY E
113. for the Warranty Period specified above the Warranty Period If Lake Shore receives notice of any such defects during the Warranty Period and the Product is shipped freight prepaid Lake Shore will at its option either repair or replace the Product if it is so defective without charge to the owner for parts service labor or associated customary return shipping cost Any such replacement for the Product may be either new or equivalent in performance to new Replacement or repaired parts will be warranted for only the unexpired portion of the original warranty or 90 days whichever is greater Lake Shore warrants the Product only if it has been sold by an authorized Lake Shore employee sales representative dealer or original equipment manufacturer OEM The Product may contain remanufactured parts equivalent to new in performance or may have been subject to incidental use The Warranty Period begins on the date of delivery of the Product or later on the date of installation of the Product if the Product is installed by Lake Shore provided that if you schedule or delay the Lake Shore installation for more than 30 days after delivery the Warranty Period begins on the 31st day after delivery This limited warranty does not apply to defects in the Product resulting from a improper or inadequate maintenance repair or calibration b fuses software and non rechargeable batteries c software interfacing parts or other sup
114. fy Inu 65 A 0 010 A 0 015 43 Set the Model 642 output current to 0 A 44 Send CALSAVE to write this calibration to non volatile memory Service 7 19 Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 13 3 6 Calibrate Current Reading Gain Send CALG 0 1 To set the output current reading gain constant to 1 Set the Model 642 output current to 20 A Ramp rate 30 A s nominal Wait 30 seconds Measure the actual voltage across the shunt and record V hunt Calculate and record Imeasuredneg V shunt Rshunt Get the Model 642 output current reading by front panel or interface and record Ireadingneg Set the Model 642 output current to 70 A Ramp rate 30 A s nominal Wait 30 seconds Measure the actual voltage across the shunt and record V hunt SEN ve AEGON Oe e BO A he Calculate and record Imeasuredpos V shunt R shunt Get the Model 642 output current reading by front panel or interface and record Ireadingpos he N Calculate gain constant per the following equation Current Reading Gain Constant Imeasuredpos Imeasuredneg Treadingpos Teadingneg 13 Verify gain factor to be 1 0 02 14 Send CALG 0 gain constant 15 Verify the Model 642 output current reading to equal Imeasuredpos F0 010 A 16 Set the Model 642 output current to 0 A 17 Send CALSAVE to write this calibration to non volatile memory
115. g Information Part Number 7 U high 19 in rack mount with integral rack mount ears 25 mm 1 in air space required on each side for ventilation 483 mm W x 310 mm H x 572 mm D 19 in x 12 2 in x 22 5 in with front handles removed 74 kg 163 lb 635 mm W x 559 mm H x 736 mm D 25 in x 22 In x 29 in 79 5 kg 175 Ib 15 C to 35 C at rated accuracy 5 C to 40 C at reduced accuracy Non condensing 30 min at output current setting CE mark low voltage compliance to EN61010 3 EMC compliance to EN55022 1 1 year Ordering Information 642 204 Model 642 70 A 35 V 2 5 kW 204 208 VAC 642 225 Model 642 70 A 35 V 2 5 kW 220 230 VAC 642 380 Model 642 70 A 35 V 2 5 kW 380 VAC 642 408 Model 642 70 A 35 V 2 5 kW 400 415 VAC Options 6041 Water flow switch 2 gallons min 6042 64X MPS water valve with mounting bracket and hose barb fittings 1 6 Introduction Lake Shore Model 642 Electromagnet Power Supply User s Manual Accessories included MAN 642 Model 642 user manual 6031 Two front handles 6032 Two rear handles 6051 Terminal block 4 pin 6052 Terminal block 8 pin 6252 15 pin D sub mating connector analog I O 108 654 Strain relief bushing kit 2225 Calibration certificate Accessories available 6201 1 m 3 3 ft long IEEE 488 GPIB computer interface cable 6261 3 m 10 ft magnet cable kit AWG 4 6262 6 m 20 ft magnet cable kit AWG 4 CAL 642 CERT Instrument recalibration with certi
116. g this procedure Identify the power wiring access panel on the rear of the Model 642 Turn the front panel line power switch OFF O Disconnect the power cable at the plug end for safety Remove the perimeter screws holding the power wiring access panel Observe the 4 voltage selection wires held by the clear plastic wiring guide See Figure 7 2 Loosen the screw terminals presently holding the four wires Relocate the 4 wires using the wiring guide to the desired voltage position Refer to Table 7 1 Place the wires into the appropriate screw terminals and tighten SOT GO E et A e Verify solid tight screw connections to these four wires o Replace the power wiring access panel using all perimeter screws hb hb Verify the voltage indicator in the window of the power wiring access panel 722 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual VOLTAGE SELECTOR CARD VOLTAGE INDICATOR KEY we HS WIRE FERRULE 208 230 0 415 208 230 0 415 208 230 0 415 E is a EES a E ES ez EY 200 208 Es 220 230 S 380 ES 400 415 200 220 S ES 400 200 S 220 400 y 200 S 220 S 400 TERMINAL SCREW DE Ol Y DE a zZz a Zz a Zz a SE deg deg deg d Figure 7 2 Voltage Change Detail 7 4 CIRCUIT BREAKER SETTING The main three phase input power is protected by an automatic reset circuit breaker within the instrument A sm
117. h 4 6 Ramp Rate Sets the output current ramp rate Refer to Paragraph 4 7 Pause Ramp Pauses the output ramp and holds the current where 1t was pause pressed Press again to continue ramp Refer to Paragraph 4 9 Zero Output Ramps the current to 0 A at the programmed ramp rate Refer to Paragraph 4 10 Remote Places the instrument to Remote mode Refer to Paragraph 5 1 2 Local Returns the instrument to Local mode if in Remote Refer to Paragraph 5 1 2 Operation 4 3 Lake Shore Model 642 Electromagnet Power Supply User s Manual 4 4 1 General Keypad Operation The Model 642 uses three basic keypad operations direct operation setting selection and data entry for the majority of operator interface A few specialized keypad operations such as ramp segment entry are described in the individual operation paragraphs Direct Operation Key functions occur immediately when the key is pressed Pause Ramp and Zero Output and are examples of keys that operate this way Setting Selection Allows the user to select from a finite list of parameter values During setting selection the _ and keys are used to select a parameter value Enter is used to accept the change and advance to the next parameter Escape will cancel the change to that parameter and return to the normal display Setting selection screens always include the message Select with Data Entry Allows the user to enter numeric parameter values using the d
118. h ON and black extended OFF push buttons Introduction Lake Shore Model 642 Electromagnet Power Supply User s Manual Specifications Continued Interface TEEE 488 2 interface Features SH1 AHI T5 L4 SR1 RL1 PPO DC1 DTO CO El Reading rate To 10 rdg s Software support National Instruments Lab VIEW driver consult Lake Shore for availability Serial interface Electrical format RS 232C Baud rates 9600 19200 38400 57600 Reading rate To 10 rdg s Connector 9 pin D sub DTE Output current monitor Sensitivity 7 V 710 A Accuracy 1 of full scale Noise 1 mV RMS Source impedance 200 Connector Shared 15 pin D sub Output voltage monitor Sensitivity 3 5 V 35 V Accuracy 1 of full scale Noise 1 mV RMS Source impedance 200 Connector Shared 15 pin D sub Power supply cooling water Remote enable input TTL low or contact closure to enable output jumper required if unused Valve power output 24 VAC at 1 A maximum automatic or manual control Connector Shared 4 pin detachable terminal block Flow switch and water valve optional Magnet cooling water Remote enable input TTL low or contact closure to enable output jumper required if unused Valve power output 24 VAC at 1 A maximum automatic or manual control Connector Shared 4 pin detachable terminal block Flow switch temperature switch and water valve not included Auxiliary Emergency stop Requires 1 A 24 VAC normally closed NC contact to enable p
119. h the present external program mode setting RESPONSE 0 term ENTER COMMAND XPGM 1 XPGM External program mode command followed by a query Instrument will change to external programming mode then return a string RESPONSE 1 term with the present setting The following are additional notes on using either IEEE 488 Interface program e 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 e 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 5 1 6 Troubleshooting New Installation Check instrument address Always send terminators Send entire message string at one time including terminators Send only one simple command at a time until communication is established Be sure to spell commands correctly and use proper syntax ont WN gt Attempt both Talk and Listen functions If one works but not the other the hardware connection is working so look at syntax terminators and command format 7 Ifonly one message is received after resetting the interface check the repeat addressing setting It should be enabled Old Installation No Longer Working 8 Power instrument off then on again to see
120. he Model 642 assumes that no valve is installed and the line for Internal Water status will not be displayed The internal water flow switch is monitored whenever the water valve is energized It is also monitored continuously when in Disabled mode to allow the use of a flow switch even when no water valve is used If no flow switch or water valve is present then a jumper must be installed across the flow switch contacts for proper operation 4 14 ERROR STATUS DISPLAY Error messages appear in the center of the instrument display when a problem is identified during operation The Fault LED will also light to indicate error conditions blinking for operational errors on continuously for instrument hardware errors Refer to Paragraph 7 6 for a listing of all the error conditions When an error condition occurs the name of the error is shown in the display alternately with Press Status Key for More Info Pressing the Status key will bring up a screen that will show an extended description of the error To enter the error status display press Status while in the main display A screen similar to the one shown below appears This screen will differ depending on the error that is being displayed If there are no errors to report the display will show No errors reported The following example shows the description for External Current Program Error 4 8 Operation Lake Shore Model 642 Electromagnet Power Supply User
121. he Status Byte bit 6 RQS MSS is not cleared Refer to paragraph 5 1 4 4 4 Self Test Query TST term lt status gt term n lt status gt 0 No errors found 1 Errors found The Model 642 reports status based on test done at power up Wait to Continue Command WAI term This command is not supported in the Model 642 RS 232C Baud Rate Command BAUD lt bps gt term n lt bps gt Specifies Baud rate 0 9600 Baud 1 19200 Baud 2 38400 Baud 3 57600 Baud RS 232C Baud Rate Query BAUD term lt bps gt term n Refer to command for description Computer Interface Operation 5 31 Lake Shore Model 642 Electromagnet Power Supply User s Manual DFLT Factory Defaults Command Input DELT 99 term Remarks Sets all configuration values to factory defaults and resets the instrument The instrument must be at zero amps for this command to work The 99 is included to prevent accidentally setting the unit to defaults DISP Display Parameter Command Input DISP lt brightness gt term Format n lt brightness gt Specifies display brightness 0 25 1 50 2 75 3 100 DISP Display Parameter Query Input DISP term Returned lt brightness gt term Format n Refer to command for definition ERCL Error Clear Command Input ERCL term Remarks This command will clear the operational errors The errors will only be cleared if the error conditions have been removed Hardware
122. he bit weighting of the error bits These error bits are latched when an error condition is detected This register is cleared when it is read Refer to Paragraph 5 1 4 3 for a list of error bits Use the ERRCL command to clear the operational errors Hardware errors cannot be cleared IEEE ITEEE 488 Interface Parameter Command Input IEEE lt terminator gt lt EOI enable gt lt address gt term Format n n nn lt terminator gt Specifies the terminator Valid entries 0 lt CR gt lt LF gt 1 lt LF gt lt CR gt 2 lt LF gt 3 No terminator must have EOI enabled lt EOI enable gt Sets EOI mode 0 Enabled 1 Disabled lt address gt Specifies the IEEE address 1 30 Address 0 and 31 are reserved Example IEEE 0 0 4 term After receipt of the current terminator the instrument uses lt CR gt lt LF gt as the new terminator uses EOI mode and responds to address 4 IEEE IEEE 488 Interface Parameter Query Input IEEE term Returned lt terminator gt lt EOI enable gt lt address gt term Format n n nn Refer to command for description lt mode gt 0 Manual Off 1 Manual On 2 Auto 3 Disabled INTWTR Internal Water Mode Command Input INTWTR lt mode gt term Format n lt mode gt 0 Manual Off 1 Manual On 2 Auto 3 Disabled Example INTWTR 2 term Places the internal water mode to Auto which will automatically control the power supply water valve based on the internal power dissipation a
123. he product or property damage caused by this product or its failure to work 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 made to the code is at the user s risk Lake Shore will assume no responsibility for damage or errors incurred as result of any changes made to the firmware Under the terms of this agreement you may only use the Model 642 firmware as physically installed in the instrument Archival copies are strictly forbidden You may not decompile disassemble or reverse engineer the firmware If you suspect there are problems with the firmware return the instrument to Lake Shore for repair under the terms of the Limited Warranty specified above Any unauthorized duplication or use of the Model 642 firmware in whole or in part in print or in any other storage and retrieval system is forbidden TRADEMARK ACKNOWLEDGMENT Many manufacturers and sellers claim designations used to distinguish their products as trademarks Where those designations appear in this manual and Lake Shore was aware of a trademark claim they appear with initial capital letters and the or symbol CalCu
124. heir back panel holes and then carefully lifting the Board assembly out of the unit 12 Locate the appropriate IC s on the main circuit board See Figure 7 6 Note orientation of existing IC CAUTION The ICs are Electrostatic Discharge Sensitive ESDS devices Wear shock proof wrist straps resistor limited to lt 5 mA to prevent injury to service personnel and to avoid inducing an Electrostatic Discharge ESD into the device 13 Use IC puller to remove existing IC s from the socket 14 Noting orientation of new IC s use an IC insertion tool to place new device s into socket s Ensure that no pins are allowed to bend CAUTION a gt LA ESD Sensitive Device g Match notch on IC to notch Typical IC in socket 15 Reinstall the Digital Board into the unit taking care to properly locate the bottom edge of the board between the four locator pins on the bottom of the instrument Push the Digital Board carefully rearward taking care to locate the rear connectors through the rear panel of the unit 16 Attach the Digital Board using the two 6 32 pan head Phillips screws removed earlier 17 Remount the IEEE 488 and RS232C connectors using the hexagonal mounting standoffs removed earlier 18 Reinstall all appropriate rear panel connections that were removed earlier Take care NOT to interchange the Magnet and Power Supply connectors 19 Reinstall all Digital Board connections removed earlier See Figure 7 6
125. his case Pin 3 on one DTE connector used for transmit must be wired to Pin 2 on the other used for receive Cables that swap the complementing lines are called null modem cables and must be used between two DTE wired devices Null modem adapters are also available for use with straight through cables Paragraph 7 10 5 illustrates suggested cables that can be used between the instrument and common computers The instrument uses drivers to generate the transmission voltage levels required by the RS 232C standard These voltages are considered safe under normal operating conditions because of their relatively low voltage and current limits The drivers are designed to work with cables up to 50 feet in length Computer Interface Operation 5 21 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 2 3 Hardware Support The Model 642 interface hardware supports the following features Asynchronous timing is used for the individual bit data within a character This timing requires start and stop bits as part of each character so the transmitter and receiver can be resynchronized between each character Half duplex transmission allows the instrument to be either a transmitter or a receiver of data but not at the same time Communication speeds of 9600 19200 38400 or 57600 Baud are supported The Baud rate is the only interface parameter that can be changed by the user Hardware handshaking is not supported by the instrument Handsha
126. hore with questions regarding shipping and packing instructions Service 7 1 Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 3 LINE VOLTAGE SELECTION The Model 642 may be configured for four basic AC power configurations 208 VAC 230 VAC 380 VAC and 415 VAC Proper voltage selection must be made before connection to the power mains Each configuration requires the appropriate wiring within the power wiring access panel on the rear of the instrument Nominal line voltages and appropriate selections are shown in Table 7 1 See Section 3 3 1 for further details See Figure 7 1 for general locations x FLOW TOA MAX 43 V MAX Be switch ZS WATER 2 1 DS OUTPUT CS5 32554 EMERGENCY STOP c CHASSIS FAULTNO FAULT COM FAULTNC REMOTE ENABLE FLOW 114A 114A SWITCH wea rea vea Teo WATER P VALVE A NDS GND ZN WARNING REPLACE cover BEFORE APPLYING POWER WATER Flow Rate 4 L 1 5 gal min Minimum Pressure 552 kPa 80 psi Maximum 3 NE VOLTAGE S CURRENITO T3A 220 230V 12A y TA 2 a 5 ae 6A OUT IN fo WF 10 VOLTAGE S060 RZ ATN i Figure 7 1 Model 642 Rear Panel shown with wiring cover removed Use the following procedure to change the instrument line voltage WARNING To avoid potentially lethal shocks turn off the power supply and disconnect it from AC power before performin
127. ield strength H The magnetizing force generated by currents and magnetic poles For most applications the magnetic field strength can be thought of as the applied field generated for example by a Electromagnet The magnetic field strength is not a property of materials Measure in SI units of A m or cgs units of oersted magnetic flux density B Also referred to as magnetic induction This is the net magnetic response of a medium to an applied field H The relationship is given by the following equation B pel M for SI and B H 4xM for cgs where H magnetic field strength M magnetization and uo permeability of free space 4r x 10 H m magnetic hysteresis The property of a magnetic material where the magnetic induction B for a given magnetic field strength H depends upon the past history of the samples magnetization magnetic induction B See magnetic flux density magnetic moment m This is the fundamental magnetic property measured with dc magnetic measurements systems such as a vibrating sample magnetometer extraction magnetometer SQUID magnetometer etc The exact technical definition relates to the torque exerted on a magnetized sample when placed in a magnetic field Note that the moment is a total attribute of a sample and alone does not necessarily supply sufficient information in understanding material properties A small highly magnetic sample can have exactly the same moment as a larger weakly magnetic sample
128. if it is a soft failure 9 Power computer off then on again to see if the IEEE 488 card is locked up 10 Verify that the address has not been changed on the instrument during a memory reset 11 Check all cable connections Intermittent Lockups 12 Check cable connections and length 13 Increase delay between all commands to 50 ms to make sure instrument is not being over loaded 5 20 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 2 SERIAL INTERFACE OVERVIEW The serial interface used in the Model 642 is commonly referred to as an RS 232C interface RS 232C is a standard of the Electronics Industries Association EIA that describes one of the most common interfaces between computers and electronic equipment The RS 232C standard is quite flexible and allows many different configurations However any two devices claiming RS 232C compatibility cannot necessarily be plugged together without interface setup The remainder of this paragraph briefly describes the key features of a serial interface that are supported by the instrument A customer supplied computer with similarly configured interface port is required to enable communication 5 2 1 Changing Baud Rate To select the Serial Interface Baud Rate press the Computer Interface key The first computer interface screen appears as a prompt for Baud Use the A or Y key to select 9600 19200 38400 or 57600 Baud The defau
129. ion Complete Query 0 0 eee 30 MAGWTR Magnet Water Mode Commanid 34 RST Reset Instrument Cmd eeeeeeeneeeee 30 MAGWTR Magnet Water Mode Query ccoococciccicnconccns 34 SRE Service Request Enable Cmd s seseseseees 31 MODE IEEE Interface Mode Cd 34 SRE Service Request Enable Query 31 MODE IEEE Interface Mode Query coococcccocccnccnnono 34 STB Status Byte Query oooonoococococonncoonoonconocnnonos 31 OPST Operational Status Ouer 35 TST Self Test Query ccocooononnccnonocononononnconocononnonno 31 OPSTE Operational Status Enable Cmd WAI Wait To Continue Cmd cooooncccccnoccconconcnnnono 31 OPSTE Operational Status Enable Query BAUD RS 232C Baud Rate Cmd wel OPSTR Operational Status Register Query BAUD RS 232C Baud Rate Query e eee 31 RATE Current Ramp Rate Setting Cmd DFLT Factory Defaults Cmd eeeeeeteereeeees 32 RATE Current Ramp Rate Setting Query DISP Display Parameter Cmd cooooonionicnnocinocicncono 32 RDGI Current Output Reading Query DISP Display Parameter Query 32 RDGV Output Voltage Reading Query L ERCL Error Clear Cistitis 32 RSEG Ramp Segments Enable Cmd ERST Error Status Query cecccescceeseeesseeseeeenes 32 RSEG Ramp Segments Enable Query ERSTE Error Status Enable Cmd cece RSEGS Ramp Segments Parameters Cmd ERSTE Error Status Enable Query RSEGS Ram
130. ith these values is possible but the accuracy will be reduced to as much as 2 of full scale generally If the Model 642 is used in closed loop operation and programmed through the external input regular calibration may not be required 7 11 1 Calibration Interface Computer interface commands are included in the Model 642 specifically for calibration These commands work with either the IEEE 488 or RS 232C interface Refer to Section 7 13 4 for a complete description of each calibration command It is always recommended to read out old calibration coefficients using the CALZ and CALG interface queries before attempting to calibrate This will give the operator experience with the interface command data formatting and typical values If the old values are saved they can be reloaded in the case of accidental loss of data during calibration New calculated calibration coefficients should be very similar to the old values Discrepancy between the old and new values of more than 0 1 of gain calibration coefficients or 0 1 of range for zero coefficients could indicate an error in the calibration procedure or a hardware failure Do not attempt to recalibrate a damaged instrument The instrument will use the new calibration coefficients as soon as they are sent with the either the CALZ or CALG interface command but they are not saved permanently until the CALSAVE command is issued If a mistake is made in the calibration process turn the instrumen
131. jo IS American Wire Gage AWG Wiring sizes are defined as diameters in inches and millimeters as follows AWG Dia In Dia mm AWG Dia In Dia mm AWG Dia In Dia mm AWG Dia In Dia mm 1 0 2893 7 348 11 0 0907 2 304 21 0 0285 0 7230 31 0 0089 0 2268 2 0 2576 6 544 12 0 0808 2 053 22 0 0253 0 6438 32 0 0080 0 2019 3 0 2294 5 827 13 0 0720 1 829 23 0 0226 0 5733 33 0 00708 0 178 4 0 2043 5 189 14 0 0641 1 628 24 0 0207 0 5106 34 0 00630 0 152 5 0 1819 4 621 15 0 0571 1 450 23 0 0179 0 4547 35 0 00561 0 138 6 0 1620 4 115 16 0 0508 1 291 26 0 0159 0 4049 36 0 00500 0 127 7 0 1443 3 665 17 0 0453 1 150 27 0 0142 0 3606 37 0 00445 0 1131 8 0 1285 3 264 18 0 0403 1 024 28 0 0126 0 3211 38 0 00397 0 1007 9 0 1144 2 906 19 0 0359 0 9116 29 0 0113 0 2859 39 0 00353 0 08969 10 0 1019 2 588 20 0 0338 0 8118 30 0 0100 0 2546 40 0 00314 0 07987 ambient temperature The temperature of the surrounding medium such as gas or liquid which comes into contact with the 1 apparatus ampere The constant current 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 x 107 newton per meter of length 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 a conducting loop carrying a current of one ampere
132. king is often used to guarantee that data message strings do not collide and that no data is transmitted before the receiver is ready In this instrument appropriate software timing substitutes for hardware handshaking User programs must take full responsibility for flow control and timing as described in Paragraph 5 2 6 5 2 4 Character Format A character is the smallest piece of information that can be transmitted by the interface Each character is 10 bits long and contains data bits bits for character timing and an error detection bit The instrument uses 7 bits for data in the ASCII format One start bit and one stop bit are necessary to synchronize consecutive characters Parity is a method of 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 5 6 Serial Interface Specifications Connector Type 9 pin D style connector plug Connector Wiring DTE Voltage Levels EIA RS 232C Specified Transmission Distance 50 feet maximum Timing Format Asynchronous Transmission Mode Half Duplex Baud Rate 9600 19200 38400 57600 Handshake Software timing Character Bits 1 Start 7 Data 1 Parity 1 S
133. l specifications 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 642 performs the functions of TALKER and LISTENER but cannot be a BUS CONTROLLER The BUS CONTROLLER is the digital computer which tells the Model 642 which functions to perform Below are Model 642 IEEE 488 interface capabilities e SL Source handshake capability e RL1 Complete remote local capability e DCL Full device clear capability e DTO No device trigger capability e CO No system controller capability e T5 Basic TALKER serial poll capability talk only unaddressed to talk if addressed to listen e L4 Basic LISTENER unaddressed to listen if addressed to talk e SRl Service request capability AHl Acceptor handshake capability e PPO No parallel poll capability El Open collector electronics Instruments are connected to the IEEE 488 bus by a 24 conductor connector cable as specified by the standard Refer to Paragraph 7 12 2 Cables can be purchased from Lake Shore or other electronic suppliers Cable lengths are limited to 2 meters for each device and 20 meters for the entire bus The Model 642 can drive a bus with up to 10 loads I
134. lement such commands do so simultaneously upon command transmission These commands transmit with the Attention ATN line asserted low The Model 642 recognizes two Multiline commands LLO Local Lockout Prevents the use of instrument front panel controls DCL Device Clear Clears Model 642 interface activity and puts it into a bus idle state Finally Addressed Bus Control Commands are Multiline commands that must include the Model 642 listen address before the instrument responds Only the addressed device responds to these commands The Model 642 recognizes four of the Addressed Bus Control Commands SDC Selective Device Clear The SDC command performs essentially the same function as the DCL command except that only the addressed device responds GTL Go To Local The GTL command is used to remove instruments from the remote mode With some instruments GTL also unlocks front panel controls if they were previously locked out with the LLO command SPE Serial Poll Enable and SPD Serial Poll Disable Serial polling accesses the Service Request Status Byte Register This status register contains important operational information from the unit requesting service The SPD command ends the polling sequence 5 1 3 2 Common Commands Common Commands are addressed commands which create commonalty between instruments on the bus All instruments that comply with the IEEE 488 1987 standard share these commands and their format
135. liance RE 4 2 4 3 3 Power Limit PED ege dE decke Ad ee A A aoe eae ieee 4 2 4 3 4 Ramping LED EE 4 2 4 3 5 aloa RE 4 2 4 4 KEYPAD DEFINITION EE EE A A AAAA 4 3 4 4 1 General Keypad Operation 4 4 4 5 DISPLAY SETUP reion R A AA A aa 4 4 4 6 SETTING OUTPUT CURRENT ccoo iia air edad 4 4 4 7 CURRENT RAMP RATE cusiiardicai dai ita 4 5 4 8 RAMP SEGMENTS eeben ee as Dee e Est 4 5 4 9 PAUSE RAM Piscina 4 6 4 10 ebe AR RE 4 6 4 11 MAXIMUM SETTING LIMITS ssc heels an ata tacos 4 7 4 11 1 Maximum e tte 4 7 4 11 2 Maximum Current Ramp Rate AAA 4 7 4 12 MAGNET WATER E E A E E E E A TE E 4 8 4 13 INTERNALWATER cite sit esate tire Atel a r ii a at 4 8 4 14 ERROR STATUS DISPLAY E 4 8 4 15 EXTERNAL CURRENT PROGRAMMING A 4 9 4 16 LOCKING THE KEYPAD EE 4 9 4 17 COMPUTER INTERFACE iaer oie en EE Ae ed 4 10 4 17 1 Changing Serial Bald Rate iii Seats cease Sek A ee ete 4 10 4 17 2 Changing IEEE 488 Interface parameters ceccceeeceeeneeeeeeeeeneeeeaeeeeaeeeeaeeseaeeseaeeeeaeeseaeeseaeeseaeeseeetes 4 11 4 18 DEFAULT PARAMETER VALUES i iech tev ita il 4 11 5 COMPUTER INTERFACE OPERATI N isos ccccccsscccecteccncecetangsccteccet cnutiesdeeteccwcoueseeadusdnacsspustdnedecceasetevesacavsueesecettenctees 5 1 5 0 EISE EE 5 1 5 1 IEE E488 INTERFACE zoranos vaeni aries seasonal a EE fede geo EENS Eed ENEE 5 1 5 1 1 Changing IEEE 488 Interface Parameiers cn nan ca nn cc nnn cnn nc rnn cnn rra 5 2 5 1 2 Remote Local Operation c 0 c0 808 aira a ahi
136. lt is 9600 Baud 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 5 2 2 Physical Connection The Model 642 has a 9 pin D Subminiature plug on the rear panel for serial communication The original RS 232C standard specifies 25 pins but both 9 and 25 pin connectors are commonly used in the computer industry Many third party cables exist for connecting the instrument to computers with either 9 or 25 pin connectors Paragraph 7 10 5 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 642 The instrument serial connector is the plug half of a mating pair and must be matched with a socket on the cable Ifa cable has the correct wiring configuration but also has a plug end a gender changer can be used to mate two plug ends together The letters DTE near the interface connector stand for Data Terminal Equipment and indicate the pin connection of the directional pins such as transmit data TD and receive data RD Equipment with Data Communications Equipment DCE wiring can be connected to the instrument with a straight through cable As an example Pin 3 of the DTE connector holds the transmit line and Pin 3 of the DCE connector holds the receive line so the functions complement It is likely both pieces of equipment are wired in the DTE configuration In t
137. m output current of the instrument DAC Processor Not Responding DAC Bit 1 This bit is set to indicate that communication to the DAC processor has failed Output Control Failure OCF Bit 0 This bit is set if there is a failure on the output control board as ae fe rejas Condition Register ERST 0510808 ve EE Error Status 7 T6 SSESRSSS 5 4 3 Event Register N EA E ERSTR Uses Usea Ussa TF oov ooc pac ocr Name To Bit 2 HESB of Status Byte Register See Figure 5 1 Error Status Enable Register ERSTE ERSTE Figure 5 4 Hardware Error Status Register 5 10 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 4 3 2 Operational Error Status Register Set The Operational Error Status Register reports the following instrument operational error events remote enable fault detected power supply flow switch fault detected magnet flow switch fault detected high line voltage low line voltage temperature high external current program error calibration error Any or all of these events may be reported in the standard event summary bit through the enable register see Figure 5 5 The Operational Error Status Register is the second value of the two values associated with the Error Status Registers The Error Status Enable command ERSTE programs the enable register and the query command ERSTE reads i
138. m iron Rhodium alloyed with less than one atomic percent iron is used to make the Lake Shore RF family of sensors Rhodium iron is a spin fluctuation alloy which has a significant temperature coefficient of resistance below 20 K where most metals rapidly lose sensitivity root mean square RMS The square root of the time average of the square of a quantity for a periodic quantity the average is taken over one complete cycle Also known as effective value RS 232C Bi directional computer serial interface standard defined by the Electronic Industries Association EIA The interface is single ended and non addressable Glossary of Terminology A 5 Lake Shore Model 642 Electromagnet Power Supply User s Manual Seebeck effect The development of a voltage due to differences in temperature between two junctions of dissimilar metals in the same circuit self heating Heating of a device due to dissipation of power resulting from the excitation applied to the device The output signal from a sensor increases with excitation level but so does the self heating and the associated temperature measurement error sensitivity The ratio of the response or change induced in the output to a stimulus or change in the input Temperature sensitivity of a resistance temperature detector is expressed as S dR dT setpoint The value selected to be maintained by an automatic controller serial interface A computer interface where information is transferr
139. m the water lines and magnet It can also be used to turn on the water in advance of a test to bring the magnet temperature to equilibrium The Off menu selection can be used to turn it off In the Disabled mode the Model 642 assumes that no valve is installed and the line for Magnet Water status will not be displayed The magnet water flow switch is monitored whenever the water valve is energized It is also monitored continuously when in Disabled mode to allow the use of a flow switch even when no water valve is used If no flow switch or water valve is present then a jumper must be installed across the flow switch contacts for proper operation 4 13 INTERNAL WATER The Model 642 provides power to control an external water solenoid control valve to control the cooling water for the power supply The setup of the valve control is available in the Internal Water menu The four menu selections are Auto On Off and Disabled with Disabled being the default setting In the Auto mode the water valve will be energized when the power in the internal power devices exceeds 100 W When the power drops below 100 W the valve will remain energized for an additional minute to remove any residual heat build up In the On mode the valve will be energized whenever the power supply is on This feature can also be used when the Model 642 is first installed to purge air from the lines The Off menu selection can be used to turn it off In the Disabled mode t
140. measured and its actual value R Shunt used to determine the actual current flow For example if the resistor is measured at 0 99661 mQ the actual current flowing is calculated by the following equation Isnunt Votuni 0 99661 x 10 or Ignunt 1000 x Vsnuni 0 99661 This resistor must withstand the full current of the Model 642 and do so with a minimum of heating that can easily change the resistance and therefore the current measurement At 70 A this resistor only dissipates 4 9 W Even so it is highly recommended to mount the resistor on a heat sink with forced air cooling to minimize temperature rise and related value changes during calibration Alpha PSBWR0010F is suggested 2 Magnet Load The Model 642 is designed for a nominal magnet load of 0 5 ohms and 0 5 H For calibration purposes the magnet can easily be used as the calibration load The calibration shunt resistor is wired in series with the positive output terminal using a cable of similar current handling capability as the normal magnet lines An alternative to this is the use of a resistor bank with total resistance of 0 5 ohms capable of safely dissipating 2 450 W of heat the equivalent of a medium sized space heater This procedure assumes the use of the water cooled magnet as a calibration load 3 DC Voltmeter DVM The voltmeter must measure VDC accurately to 10 s of uV if resolution to 10 s of mA from the Model 642 The Agilent Model 34401 DMM or better is
141. n and return to the normal display When output current is called for using the Output Setting key the output will ramp to the desired current using the ramp segment set points 4 9 PAUSE RAMP The Pause Ramp key will pause the output current ramp within two seconds after the key is pressed While the output current ramp is paused the Ramping LED will blink Pressing the Pause Ramp key again will continue the ramping Pressing the Enter key while the ramp is paused will set the current at the paused setting and exit the Pause Ramp mode 4 10 ZERO OUTPUT The Zero Output key on the front panel can be used to set the output current to 0 A When the Zero Output key is pressed the current output will begin to ramp down using the current ramp rate This key is equivalent to using the Output Setting key and entering 0 A except that it works even when the Model 642 is being programmed externally Refer to Paragraph 4 6 to set the output current NOTE The current ramp rate applies only to the internal current output setting When the Model 642 is programmed externally the drop to zero output when the Zero Output key is pressed will be quite rapid 1 second and limited primarily by the magnet reactance and the Model 642 voltage compliance limit The voltage compliance LED may light during the change 4 6 Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 4 11 MAXIMUM SETTING LIMITS The Model 642 offers a maximum
142. n the magnet The water can be turned on and off manually when the magnet is used or automatically with a solenoid valve The Model 642 provides automatic control and a 24 VAC at 1 A output for this purpose The optional water valve is shown in Figure 2 2 The water inlet line should also be fitted with a sediment filter not shown to reduce scale build up in the magnet coils and connecting lines 2 3 5 Grounding A ground connection tapped hole is usually available at the rear of the electromagnet frame This ground point is provided for customers who would like to use the electromagnet frame as a signal ground or will be bringing hazardous live voltages near the electromagnet and would like to make it an electrical safety ground Please verify suitability for such a function and compatibility with local and national electrical codes before making ground connections Scrape off excess paint near the connecting screw to ensure a good electrical contact with the bare steel of the electromagnet frame 2 4 Magnet System Design Lake Shore Model 642 Electromagnet Power Supply User s Manual 2 3 6 Final Check Out When all of the connections have been made the system should be tested to be sure it is operating correctly The settings for the magnet water should be checked to verify that they are correct for the configuration which has been installed Refer to Section 4 12 Magnet Water The maximum current setting for the magnet should be set
143. nal or accidental by which an electric circuit or equipment is connected to the Earth or to some conducting body of relatively large extent that serves in place of the Earth Note It is used for establishing and maintaining the potential of the Earth or of the conducting body or approximately that potential on conductors connected to it and for conducting ground current to and from the Earth or of the conducting body H Symbol for magnetic field strength See Magnetic Field Strength Hall effect The generation of an electric potential perpendicular to both an electric current flowing along a thin conducting material and an external magnetic field applied at right angles to the current Named for Edwin H Hall 1855 1938 an American physicist hertz Hz A unit of frequency equal to one cycle per second hysteresis The dependence of the state of a system on its previous history generally in the form of a lagging of a physical effect behind its cause Also see magnetic hysteresis IEC International Electrotechnical Commission IEEE Institute of Electrical and Electronics Engineers TEEE 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 at H 0 and M 0 infrared IR For p
144. nd temperature INTWTR Internal Water Mode Query Input INTWTR term Returned lt mode gt term Format n Refer to command for description KEYST Keypad Status Query Input KEYST term Returned lt code gt term Format nn Remarks Returns a number descriptor of the last key pressed since the last KEYST Returns 01 after initial power up Returns 00 if no key pressed since last query Computer Interface Operation 5 33 Lake Shore Model 642 Electromagnet Power Supply User s Manual LIMIT Input Format Remarks LIMIT Input Returned Format LOCK Input Format Remarks Example LOCK Input Returned Format Limit Output Settings Command LIMIT lt current gt lt rate gt term nn nnnn nn nnnn lt current gt Specifies the maximum output current setting allowed 0 70 1000 A lt rate gt Specifies the maximum output current ramp rate setting allowed 0 0001 99 999 A s Sets the upper setting limits for output current compliance voltage and output current ramp rate This is a software limit that will limit the settings to these maximum values Limit Output Settings Query LIMIT term lt current gt lt rate gt term nn nnnn nn nnnn Refer to command for description Keypad Lock Command LOCK lt state gt lt code gt term n nnn lt state gt 0 Unlock 1 Lock All 2 Lock Limits lt code gt Specifies lock out code
145. ndensation can occur Condensation inside the power supply can cause severe damage To avoid condensation the power supply operator must remain cognizant of the ambient air temperature cooling water temperature and the relative humidity Lake Shore defines the limits of these conditions as follows ambient temperature 18 28 C 64 82 F cooling water temperature 15 25 C 59 77 F and humidity 20 80 non condensing Knowing the actual state of these conditions the operator can calculate the dew point or temperature at which condensation will occur Tables 2 1 and 2 2 are included to aid in dew point calculation Table 2 1 Dew Point Calculation Table In Degrees Celsius Relative Humidity C 100 S 9 Bil HAY 727 6 CO 55 5 4 40 3 30 25 20 1 B5 10 32 32 31 31 29 28 27 26 24 23 22 20 18 17 15 12 9 6 2 0 29 29 28 27 27 26 24 23 22 21 19 18 16 14 12 10 7 3 0 S 27 27 26 25 24 23 22 21 19 18 17 15 13 12 10 7 4 2 0 7 24 24 23 22 21 20 19 18 17 16 14 13 11 5 2 0 21 21 20 19 18 17 16 15 14 13 12 10 8 3 0 S 0 18 18 17 17 16 15 14 13 12 10 9 7 6 N sl O IN BEB J 16 16 14 14 13 12 11 10 9 7 6 5 3 Table 2 2 Dew Point Calculation Table In Degrees Fahrenheit
146. ng and lifting 3 2 Installation Lake Shore Model 642 Electromagnet Power Supply User s Manual QUTPUT a COOS A A re ANALOGIO g FAULT GOM 114A ua zeng 2 le ie g ZN WARNING REPL cover serore apatyna PONER WATER Flow Rate 4 L 1 5 gal min Minimum Pressure 552 kPa 80 psi Maximum OUT IN 15 44 e 13 5 a 45 Figure 3 1 Model 642 Rear Panel shown with wiring cover removed 3 3 POWER WIRING AND SET UP This section describes how to properly connect the Model 642 to the line power Please follow these instructions carefully to ensure proper operation of the instrument and the safety of operators 3 3 1 Line Voltage Selection The Model 642 has four AC line voltage configurations covering seven different input voltages The nominal voltage and voltage tap setting as well as the circuit breaker current setting for each configuration is shown in Table 3 2 Verify that the unit is configured correctly for the voltage being applied to the unit before applying power Table 3 2 Voltage and Current Selection Nominal Voltage Circuit Voltage Tap Breaker 200 V 204 V 18A 208 V 204 V 18A 220 V 225 V 17A 230 V 225 V 17A 380 V 380 V 12A 400 V 408 V 12A 415V 408 V 12A Installation 3 3 Lake Shore Model 642 Electromagnet Power Supply User s Manual Line Voltage Sel
147. ng point The temperature at which a substance in the liquid phase transforms to the gaseous phase commonly refers to the boiling point at sea level and standard atmospheric pressure calibrate To determine by measurement or comparison with a standard the correct value of each scale reading on a meter or other device or the correct value for each setting of a control knob Carbon Glass A temperature sensing material fabricated from a carbon impregnated glass matrix used to make the Lake Shore Carbon Glass Resistor CGR family of sensors Celsius C Scale A temperature scale that registers the freezing point of water as 0 C and the boiling point as 100 C under normal atmospheric pressure Celsius degrees are purely derived units calculated from the Kelvin Thermodynamic Scale Formerly known as centigrade See Temperature for conversions Cernox A Lake Shore resistance temperature detector based on a ceramic oxy nitride resistance material cgs system of units A system in which the basic units are the centimeter gram and second Chebychev polynomials A family of orthogonal polynomials which solve Chebychev s differential equation Chebychev differential equation A special case of Gauss hypergeometric second order differential equation 1 x f x xf x nf x 0 closed loop See feedback control system coercive force coercive field The magnetic field strength H required to reduce the magn
148. nstrument does an internal diagnostic and makes sure everything is working Most of the instrument setup parameter values are retained when power is off with a few exceptions The output current will always be set to 0 A anytime the instrument is powered up When the instrument is powered on for the first time parameter values are set to their defaults as listed in Table 4 3 When initialization is complete the instrument will begin its normal reading cycle Current and voltage readings should appear on the display Any error messages will appear in the center of the display Messages listed in Table 7 2 Instrument Hardware Errors are related to the instrument hardware and may require help from Lake Shore service The messages listed in Table 7 3 Operational Errors are related to instrument operation and may be corrected with user intervention The Model 642 should be allowed to warm up for a minimum of 30 minutes to achieve rated accuracy Operation 4 1 Lake Shore Model 642 Electromagnet Power Supply User s Manual 4 2 DISPLAY DEFINITION The Model 642 has an 8 line by 40 character vacuum fluorescent VF display capable of showing both text and graphic images The features displayed during normal operation include current measurement voltage measurement current programming ramp rate magnet water status internal water status program mode and internal temperature Other display configurations appear during parameter setting and
149. o move it by hand a minimum of two people is required CAUTION To avoid injury to personnel always observe proper lifting techniques in accordance with OSHA and other regulatory agencies Installation 3 1 Lake Shore Model 642 Electromagnet Power Supply User s Manual 3 2 REAR PANEL DEFINITION This paragraph defines the rear panel of the Model 642 Refer to Table 3 1 Readers are referred to paragraphs that contain installation instructions and connector pin outs for each feature CAUTION Verify that the Model 642 has been set up for the proper line voltages CAUTION Make rear panel connections with the instrument power off Table 3 1 below highlights the connections to be made on the rear panel Figure 3 1 shows the rear panel and identifies the connectors Table 3 1 Rear Panel Connector Identification 1 VOLTAGE 16 DIN terminals are provided behind a wiring cover to facilitate setting the correct input SELECTION voltage 2 CIRCUIT An adjustable current auto resetting circuit breaker is provided behind a wiring cover to BREAKER protect main power circuits 3 FUSES Ya A Class CC fuses 2 are provided behind a wiring cover to protect the start up circuit 4 CABLE ENTRY A 34 mm 1 3 inch hole is provided for power cable entry and strain relief bushing 5 POWER Four DIN terminals are provided behind a wiring cover for connection of power wirin TERMINALS K 6 MAGNET A 4 pin
150. onse immediately e Receive the entire response from the instrument including the terminators e Guarantee that no other communication is started during the response or for 50 ms after it completes e Not initiate communication more than 20 times per second Failure to follow these simple rules will result in inability to establish communication with the instrument or intermittent failures in communication 5 2 7 Serial Interface Example Programs A Visual BASIC program is included to illustrate the serial communication functions of the instrument Refer to Paragraph 5 2 7 1 for instructions on how to setup the program The Visual Basic code is provided in Table 5 8 Refer to Paragraph 5 2 7 2 for instructions on how to setup the program A description of operation is provided in Paragraph 5 2 7 2 While the hardware and software required to produce and implement these programs not included with the instrument the concepts illustrated apply to almost any application where these tools are available Computer Interface Operation 5 23 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 2 7 1 Visual Basic Serial Interface Program Setup The serial interface program works with Visual Basic 6 0 VB6 on an IBM PC or compatible with a Pentrum 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 proce
151. onstant value Remarks Items marked with a are for internal diagnostic use only and should always be set to a value of 0 default CALZ Zero Offset Calibration Constant Query Input CALZ lt type gt term Format nn lt type gt 0 10 Returned lt value gt term Format nnnnnnn Refer to command for description 7 22 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual APPENDIX A GLOSSARY OF TERMINOLOGY accuracy The degree of correctness with which a measured value agrees with the true value electronic accuracy The accuracy of an instrument independent of the sensor sensor accuracy The accuracy of a temperature sensor and its associated calibration or its ability to match a standard curve American Standard Code for Information Interchange ASCII A standard code used in data transmission in which 128 numerals letters symbols and special control codes are represented by a 7 bit binary number as follows DO COIN DU A Ww mu O D Illu Fitalb l jO Jia a j lt x z lt fe gt om y o DS lt ix E lt ciAjuojajojo u lolololololololo olololo lololo lo H olo o o olo lolo g lol o o o Jo s o Jo Jol o 3 3 x e 5 o alo ajo ojala o Olzlz r ixic nHiiio aimojojo r MY LAT ke mo
152. orts the voltage at the output terminals with a resolution of 0 1 mV All output readings can be prominently displayed on the front panel and read over the computer interface Protection The Model 642 continuously monitors the line voltage load power internal power and load resistance as well as a variety of other internal circuit parameters for signs of trouble Some fault conditions result in a warning message while others will provide a warning message and zero the output When hazardous conditions exist the Model 642 will shut itself off NOTE The Model 642 is equipped with a high line lockout circuit which will prevent the unit from being turned on if it is connected to a voltage source that is much higher than the voltage for which it is configured fae Ges BI akeShore Mode 642 Electromagnet Power Supply Figure 1 1 Model 642 Front Panel 1 2 Introduction Lake Shore Model 642 Electromagnet Power Supply User s Manual Description Continued Interfaces The Model 642 includes IEEE 488 and RS 232C interfaces that provide access to operating data stored parameters and remote control of all front panel operated functions A keypad lock out feature is provided to prohibit any changes made from the front panel The Model 642 can then be operated solely with the computer via the RS 232C or IEEE 488 interface The Model 642 provides two analog outputs
153. output setting is set to 0 A and no current entry will be allowed The error message will flash for 10 seconds then the Model 642 will turn itself off Output Over Voltage The measured output current exceeded 73 A The output setting is set to 0 A and no Output Over Current current entry will be allowed The error message will flash for 10 seconds then the Model 642 will turn itself off The processor that controls the output DAC is not responding or is responding incorrectly The output setting is set to 0 A and no current entry will be allowed Cycle power to attempt to clear DAC Processor not Responding One of the internally monitored voltages is beyond an acceptable range on power up Output Control Failure The output setting is set to 0 A and no current entry will be allowed Cycle power to clear attempt to clear Service 7 5 Lake Shore Model 642 Electromagnet Power Supply User s Manual Table 7 3 Operational Errors Remote Enable Fault Detected The Remote Enable connection loop is not closed The output setting is set to 0 A and no current entry will be allowed Once the loop is closed the error is cleared by pressing the STATUS key or sending ERCL over computer interface Power Supply Flow Switch Fault Detected The Power Supply Flow Switch connection loop is not closed The output setting is set to 0 A and no current entry will be allowed Once the loop is closed the error is clea
154. ower up jumper required if unused Fault output Relay with normally open NO or normally closed NC contact 30 VDC at 1 A Remote enable TTL low or contact closure to enable output jumper required if unused Connector Shared 8 pin detachable terminal block Emergency stop and enable switches not included Introduction Lake Shore Model 642 Electromagnet Power Supply User s Manual Specifications Continued General Line power Power Voltage and current Protection Frequency Configuration Connector 5500 VA max 200 208 VAC 10 13 A phase 220 230 VAC 10 12 A phase 380 VAC 10 7 A phase 400 415 VAC 10 6 5 A phase Three phase thermal relay with adjustable current setting Two class CC 1 4 A fuses Over voltage lockout circuit 50 Hz or 60 Hz 3 phase delta 4 pin terminal block Line voltage must be specified at time of order but is field reconfigurable Cable from power supply to facility power not included Cooling water Flow rate Pressure range Pressure drop Temperature Connection 5 7 L 1 5 gal min minimum 34 kPa 5 psi to 552 kPa 80 psi 10 kPa 1 5 psi at 5 7 L 1 5 gal minute minimum for power supply only 15 C to 30 C non condensing Two 10 mm 0 38 in hose barbs CAUTION Internal condensation can cause damage to the power supply Enclosure type Size Weight Shipping size Shipping weight Ambient temperature Humidity Warm up Approvals Calibration schedule Orderin
155. p Segments Parameters Query ERSTR Error Status Register Query c cceeees SETI Output Current Setting Cd IEEE IEEE 488 Interface Parameter Cmd 33 SETI Output Current Setting Query eee IEEE IEEE 488 Interface Parameter Query 33 STOP Stop Output Current Ramp Cmd 37 INTWR Internal Water Mode Command 33 XPGM External Program Mode Cmd 00 37 XPGM External Program Mode Query 37 5 3 1 Interface Commands Alphabetical Listing CES Input Remarks ESE Input Format Remarks Clear Interface Command CLS term Clears the bits in the Status Byte Register and Standard Event Status Register and terminates all pending operations Clears the interface but not the instrument The related instrument command is RST Standard Event Status Enable Register Command ESE lt bit weighting gt term nnn The Standard Event Status Enable Register determines which bits in the Standard Event Status Register will set the summary bit in the Status Byte This command programs the enable register using a decimal value that corresponds to the binary weighted sum of all bits in the register Refer to Paragraph 5 1 4 2 1 Computer Interface Operation 5 29 Lake Shore Model 642 Electromagnet Power Supply User s Manual ESE Standard Event Status Enable Register Query Input ESE term Returned lt bit w
156. placed in the output buffer This function is typically used to signal a completed operation without monitoring the SRQ It is also used when it is important to prevent any additional communication on the bus during a pending operation 5 1 5 IEEE 488 Interface Example Programs A Visual Basic program is included to illustrate the IEEE 488 communication functions of the instrument Instructions for setting up the IEEE 488 Board is included in Section 5 1 5 1 Refer to Section 5 1 5 2 for instructions on how to setup the program The Visual Basic code is provided in Table 5 5 A description of program operation is provided in Section 5 1 5 3 While the hardware and software required to produce and implement these programs not included with the instrument the concepts illustrated apply to most applications 5 1 5 1 IEEE 488 Interface Board 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 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 These files will be used during the development process of a Visual Basic program a Niglobal
157. plies By optimizing output power Lake Shore was able to concentrate on the performance requirements of the most demanding magnet users The resulting Model 642 provides high precision low noise safety and convenience Precision in magnetic measurements is typically defined as smooth continuous operation with high setting resolution and low drift Achieving these goals while driving an inductive load requires unique solutions The Model 642 delivers up to 70 A at a nominal voltage of 35 V with the supply acting as either a source or a sink in true 4 quadrant operation Its current source output architecture with analog control enables both smooth operation and low drift A careful blending of analog and digital circuits provides high setting resolution of 0 1 mA and flexible output programming Lake Shore chose linear input and output power stages for the nominal 2450 W output of the Model 642 Linear operation eliminates the radiated radio frequency RF noise associated with switching power supplies allowing the Model 642 to reduce the overall noise in its output and the noise radiated into surrounding electronics Safety should never be an afterthought when driving an inductive load The Model 642 incorporates a variety of hardware and firmware protection features to ensure the safety of the magnet and supply For improved operator safety the power supply was also designed for compliance with the safety requirements of the CE mark including both
158. plies not furnished by Lake Shore d unauthorized modification or misuse e operation outside of the published specifications or f improper site preparation or maintenance TO THE EXTENT ALLOWED BY APPLICABLE LAW THE ABOVE WARRANTIES ARE EXCLUSIVE AND NO OTHER WARRANTY OR CONDITION WHETHER WRITTEN OR ORAL IS EXPRESSED OR IMPLIED LAKE SHORE SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OR CONDITIONS OF MERCHANTABILITY SATISFACTORY QUALITY AND OR FITNESS FOR A PARTICULAR PURPOSE WITH RESPECT TO THE PRODUCT Some countries states or provinces do not allow limitations on an implied warranty so the above limitation or exclusion might not apply to you This warranty gives you specific legal rights and you might also have other rights that vary from country to country state to state or province to province TO THE EXTENT ALLOWED BY APPLICABLE LAW THE REMEDIES IN THIS WARRANTY STATEMENT ARE YOUR SOLE AND EXCLUSIVE REMEDIES EXCEPT TO THE EXTENT PROHIBITED BY APPLICABLE LAW IN NO EVENT WILL LAKE SHORE OR ANY OF ITS SUBSIDIARIES AFFILIATES OR SUPPLIERS BE LIABLE FOR DIRECT SPECIAL INCIDENTAL CONSEQUENTIAL OR OTHER DAMAGES INCLUDING LOST PROFIT LOST DATA OR DOWNTIME COSTS ARISING OUT OF THE USE INABILITY TO USE OR RESULT OF USE OF THE PRODUCT WHETHER BASED IN WARRANTY CONTRACT TORT OR OTHER LEGAL THEORY AND WHETHER OR NOT LAKE SHORE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES Your use of the Product is entirel
159. ractical purposes any radiant energy within the wavelength range 770 to 10 nanometers is considered infrared energy The full range is usually divided into three sub ranges near IR far IR and sub millimeter interchangeability Ability to exchange one sensor or device with another of the same type without a significant change in output or response international system of units SI A universal coherent system of units in which the following seven units are considered basic meter kilogram second ampere Kelvin mole and candela The International System of Units or Syst me International d Unit s SI was promulgated in 1960 by the Eleventh General Conference on Weights and Measures For definition spelling and protocols see Reference 3 for a short convenient guide interpolation table A table listing the output and sensitivity of a sensor at regular or defined points which may be different from the points at which calibration data was taken intrinsic coercivity The magnetic field strength H required to reduce the magnetization M or intrinsic induction in a magnetic material to zero intrinsic induction The contribution of the magnetic material B to the total magnetic induction B B B poH SI B B H cgs isolated neutral system A system that has no intentional connection to ground except through indicating measuring or protective devices of very high impedance Kelvin K The unit of temperature on the
160. read using the appropriate query command Some registers clear when read others do not Refer to Paragraph 5 1 4 1 7 The response to a query will be a decimal value that corresponds to the binary weighted sum of all bits in the register Refer to Table 5 1 The actual query commands are described later in this section Reading Registers Table 5 1 Binary Weighting of an 8 Bit Register Position B7 B6 BS B4 B3 B2 Bl BO Decimal 128 64 32 16 8 4 2 1 Weighting 2 2 2 a 2 de 2 7 Example If bits 0 2 and 4 are set a query of the register will return a decimal value of 21 1 4 16 5 1 4 1 7 The only registers that may be programmed by the user are the enable registers All other registers in the status system are read only registers To program an enable register send a decimal value which corresponds to the desired binary weighted sum of all bits in the register Refer to Table 5 1 The actual commands are described later in this section Programming Registers 5 1 4 1 8 Clearing Registers The methods to clear each register are detailed in Table 5 2 Table 5 2 Register Clear Methods Register Method Example Condition Registers None registers are not latched Event Registers Standard Event Status Register Operation Event Register Error Status Event Register Enable Registers Standard Event Status Enable Register Operation Event Enable Register E
161. record Imaxnegtrim Nam Raum 23 Send CALG 10 100 To set the output current gain trim constant to minimum 24 Wait 10 seconds 25 Measure the actual voltage across the shunt and record V sunt 26 Calculate and record Iminnegtrim VshuntR shunt 27 Send CALG 10 0 To return the output current gain trim constant to 0 28 Set the Model 642 output current to 0 A 29 Calculate the gain constant per the following equation Current Output Gain Constant 200 Lmax Lmin 130 CImaxpostrim Iminpostrim Imaxnegtrim Iminnegtrim 30 Send CALG 10 gain constant This method while somewhat lengthy averages the trim spans between negative and positive settings to split the error between positive and negative operation This gain calibration may shift the initial zero calibration for the Current Output DAC slightly It is best to repeat the current zero calibrations at this point 31 Recalibrate Current Output Zero refer to Section 7 13 3 1 32 Recalibrate Current Reading Zero refer to Section 7 13 3 2 33 Set the Model 642 output current to 65 A ramp rate 30 A s nominal 34 Wait 30 seconds 35 Measure the actual voltage across the shunt and record V srun 36 Calculate and record lout V shun Rshunt 37 Verify Le 65 A 0 010 A 0 015 39 Set the Model 642 output current to 65 A ramp rate 30 A s nominal 40 Wait 30 seconds 41 Calculate and record Jou Vstun R shunt 42 Veri
162. red by pressing the STATUS key or sending ERCL over computer interface Magnet Flow Switch Fault Detected The Magnet Flow Switch connection loop is not closed The output setting is set to 0 A and no current entry will be allowed Once the loop is closed the error is cleared by pressing the STATUS key or sending ERCL over computer interface High Line Voltage Detected The Output Stage Voltage Out Stg V is greater than 66 V The most likely cause is a power mains voltage that is too high This error will clear when the power mains voltage is within specified tolerances Continued operation is allowed but may not be optimal Low Line Voltage Detected The Output Stage Voltage Out Stg V is less than 44 V The most likely cause is a power mains voltage that is too low This error will clear when the power mains voltage is within specified tolerances Continued operation is allowed but may not be optimal Internal Temperature High Cold Plate temperature is over 40 C The output setting is set to 0 A and no current entry will be allowed The error will clear when the Cold Plate temperature falls below 40 C This may be indicative of low cooling water flow or high water temperature External Current Program Error The instrument was not allowed to change to external or sum current programming modes including power up because the programming voltage was greater than 0 025 V This error can be cleared wh
163. resistance lower than the supply s rated minimum the power required may be higher than the devices can safely handle If this happens the power in the devices is prevented from exceeding the safe limit and the Power Limit LED will light to alert the operator to the condition The led will go out when the condition clears 4 3 4 Ramping LED The Ramping LED lights whenever the internal control circuitry is changing the output current When the ramp is completed and the current is at the desired point the LED goes out The LED does not light when the output current is being controlled by an external source 4 3 5 Remote LED The Remote LED is lit when the Remote key has been pressed to accept remote computer programming input or upon receiving the first command over the IEEE bus When the LED is lit the main keypad is locked out Pressing the Local key will return the unit to the local mode and reestablish keypad functions 4 2 Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 4 4 KEYPAD DEFINITION The Model 642 has 22 keys separated into 3 groups on the instrument front panel The sixteen keys in the center of the grouping combines instrument setup and data entry The keys below control the output current and ramping The keys to the right control the computer interface mode of the instrument See Figure 4 2 for key locations Refer to Table 4 2 for keypad descriptions Magnet Internal Display Water Water Set
164. rminals cia A a 3 5 3 3 6 WIFI COVER aio al Sead steelhead je eee gi et 3 6 3 3 7 Mains Wining DEE 3 7 3 4 MAGNET CONNECTOR eii e eee eran Date eee 3 7 3 5 AUXILIARY CONNECTOR wy exten coheed tind eh ai death Bint eee a eee Sa 3 7 3 6 POWER SUPPLY CONNECTOR icon ainda atienda 3 8 3 7 GCOOLING WATER cocinado to os ES e e an RES 3 8 3 8 MAGNET CABLE CONNECTIONS oococcocccconccnoncnonnnonancnnancnnoncnnnnncnnnnnnnnn cnn rare rc rn rare rn nn rn nnnr cnn na rnnnnraniens 3 9 3 9 ANALOG INPUT OUTPUT CONNECTIONS AA 3 11 3 9 1 External Current Programming nono nr arc a aa rca 3 11 3 9 2 Output Current and Voltage Monitors cecceeeceeeseeeeeeeeeneeeeeeeeaeeeeaeeeeaeeeeaeeeeaeeseaeeseaeeseaeeseaeeeeeeaas 3 11 3 10 COMPUTER INTERFAGE sucios ridad 3 11 3 10 1 RS 2320 Interface COMEN nas 3 11 3 10 2 IEEE 488 Interface Connection i ca iinis neieiet identeeon he ea rra 3 11 3 11 CHASSIS CONNECTION 4328 diced ie dee Ad 3 11 3 12 DETACHABLE HANDLES ue ae tenn nian ee ee ee eee 3 12 3 13 RACK MOUNTING nieces A a etn et eo ee ed dE 3 12 Table of Contents Lake Shore Model 642 Electromagnet Power Supply User s Manual TABLE OF CONTENTS Continued Chapter Section Title Page d OPERATION in 4 1 4 0 GENERAL ada ta aaa 4 1 4 1 TURNING ROWER ON eegen ebessen idee geesde AER 4 1 4 2 DISPLAY DERIN ON Leger gege ERR 4 2 4 3 LED ANNUNGIATORS iii ad eddie iio 4 2 4 3 1 Fault EDs tee pian ie se acs SSS Ee EE A Dh e ge aa 4 2 4 3 2 Comp
165. rror Status Enable Register Service Request Enable Register Query the event register Send CLS ESR clears Standard Event Status register CLS clears all three registers Power on instrument Write 0 to the enable register ESE 0 clears Standard Event Status Enable register Power on instrument Status Byte There are no commands that directly clear the Status Byte as the bits are non latching To clear individual summary bits clear the event register that corresponds to the summary bit Sending CLS will clear all event registers which in turn clears the status byte If bit 5 ESB of the Status Byte is set send ESR to read the Standard Event Status Register and bit 5 will clear Power on instrument Computer Interface Operation 5 7 Lake Shore Model 642 Electromagnet Power Supply User s Manual 5 1 4 2 Status Register Sets As shown in Figure 5 1 there are five register sets in the status system of the Model 642 Standard Event Status Register Operation Event Register Hardware Error Status Register Operational Error Status Register and the Persistent Switch Error Register 5 1 4 2 1 Standard Event Status Register Set The Standard Event Status Register reports the following interface related instrument events power on detected command syntax errors command execution errors query errors operation complete Any or all of these events may be reported in
166. rve Cernox Duo Twist Quad Lead Quad Twist Rox and SoftCal are trademarks of Lake Shore Cryotronics Inc MS DOS and Windows are trademarks of Microsoft Corp NI 488 2 is a trademark of National Instruments PC XT AT and PS 2 are trademarks of IBM Copyright 2006 by Lake 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 ii Lake Shore Model 642 Electromagnet Power Supply User s Manual CE DECLARATION OF CONFORMITY Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville OH 43082 8888 USA hereby declare that the equipment specified conforms to the following Directives and Standards 73 23 EEC 89 336 EEC EN 61010 1 2001 Overvoltage II Pollution Degree 2 EN 61326 A2 2001 Class A Annex B Model Numbers coe ee eee ee ees 642 gd Valf sei Edward Maloof Printed Name Vice President of Engineering Position 111 Lake Shore Model 642 Electromagnet Power Supply User s Manual This Page Intentionally Left Blank iv Lake Shore Model 642 Electromagnet Power Supply User s Manual TABLE OF CONTENTS Chapter Section Title Page 1 INTRODUCTION oae eege dai 1 1 1 0 GENERAL ee Eesen eeh eta OG E chs cca eeneg Ee 1 1 1 1 DESC
167. s Manual 4 15 EXTERNAL CURRENT PROGRAMMING The output current of the Model 642 can be set internally externally or by the sum of the external and internal settings Normally the current is controlled internally by entering a setting from the front panel using the Output Setting key Refer to Paragraph 4 6 to set the output current When the external program mode is set to External the front panel setting is fixed at 0 A and the output current is set using an external voltage where 10 V 70 A When the external program mode is set to Sum the internal and external settings are summed together to set the output current When using the External or Sum modes care must be taken to insure that the output current does not exceed the maximum current for the magnet The software maximum setting limits cannot limit the output current or ramp rate that is set when using the External or Sum modes A 3 dB 40 Hz two pole low pass filter limits the bandwidth of the external current programming input The bandwidth of the output is also limited by the compliance voltage and the inductance of the magnet To configure the external current program mode press External Program The following setup screen appears as a prompt for the external current program mode Use the A or Y key to select the external current program mode Internal External or Sum Press Enter to accept the new selection and return to the normal display Press Escape to cancel
168. sage available bit The bits of the Status Byte Register are described as follows Operation Summary OSB Bit 7 Set summary bit indicates that an enabled operation event has 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 bus is set this is the RQS function of the bit See Paragraph 5 1 4 4 3 In addition the status of the bit may be read with the STB query which returns the binary weighted sum of all bits in the Status Byte this is the MSS function of the bit Performing a serial poll will automatically clear the RQS function but not the MSS function A STB will read the status of the MSS bit along with all of the summary bits but also will not clear it To clear the MSS bit either clear the event register that set the summary bit or disable the summary bit in the Service Request Enable Register Event Summary ESB Bit 5 Set summary bit indicates that an enabled standard event has occurred Message Available MAV Bit 4 Set summary bit indicates that a message is available in the output buffer Bit 3 Not used Hardware Errors Summary HESB Bit 2
169. sen for the current drawn and the length of cable used To minimize shock hazard the electrical ground safety ground lead must be connected If a flexible cable and plug are used plug the power cable into an approved electrical outlet The power jack and mating plug of the power cable must meet Underwriters Laboratories UL and International Electromechanical Commission IEC safety standards Power wiring must comply with electrical codes of the locality in which the unit is installed Ventilation The instrument has ventilation holes in its side panels Do not block these holes when the instrument is operating Provide at least 25 mm 1 in of air space on each side for ventilation Do Not Operate In An Explosive Atmosphere Do not operate the instrument in the presence of flammable gases or fumes Operation of any electrical instrument in such an environment constitutes a definite safety hazard Keep Away From Live Circuits Operating personnel must not remove instrument covers Refer component replacement and internal adjustments to qualified maintenance personnel Do not replace components with power cable connected To avoid injuries always disconnect power and discharge circuits before touching them Introduction 1 7 Lake Shore Model 642 Electromagnet Power Supply User s Manual Safety Summary Continued Do Not Substitute Parts Or Modify Instrument Do not install substitute parts or perform any unauthorized modification to th
170. setting limit for output current and ramp rate Typical properties of the magnet will dictate these parameters These maximum parameters should be entered before the magnet system is used to prevent damage 4 11 1 Maximum Output Current Maximum Output Current limits the output current that can be entered This setting will only limit the internal output current setting If the output current is being programmed by an external voltage then some external provision must be made to insure that the programming voltage will never exceed the desired output current See Paragraph 4 15 to setup the External Current Programming mode To set the maximum output current limit press Max Settings The first maximum setting screen appears as a prompt for the maximum output current limit Use the data entry keys to enter the maximum output current limit value between 0 0000 and 70 0000 A Press Enter to accept the new value Press Escape to restart the setting sequence and enter a different value Press Escape again to leave the setting sequence NOTE The maximum output current limit value can be set as high as 70 1000 A This can be used to compensate for variances in calibration The output current is guaranteed to reach a minimum of 70 A into a 0 5 ohm load but may not be able to reach 70 1 A in all circumstances 4 11 2 Maximum Current Ramp Rate Maximum Current Ramp Rate limits the maximum current ramp rate that can be entered This setting
171. siatica td dle 7 14 7 10 7 IEEE 488 Parallel Interface Connector ooooconncccnnccconccconcnnonccconononnnnnanc crono nrnnc crac nr cnn rca nc rra nc 7 14 7 11 CALIBRA TON EE 7 16 7 11 1 E lee lef ur TEE 7 16 7 11 2 Calibration See TEE 7 17 7 11 3 Calibration Procedure sci cities lista ageet ethene ded peed vei eich ve eh ie 7 17 7 11 3 1 Calibrate Current Qutp t Zero ee aces tdt std heated bs het etn 7 17 7 11 3 2 Calibrate Current Reading Zero AAA 7 17 7 11 3 3 Calibrate Output Voltage Reading Zero 7 18 7 11 3 4 Calibrate External Program Voltage Reading Zem 7 18 7 11 3 5 Calibrate Output Current Gain Span ooonccccnccinnccnonccnncncnonnnnnrnnnnnc crac narran arrancar 7 18 7 11 3 6 Calibrate Current Reading Gan 7 20 7 11 3 7 Calibrate Voltage Reading Gan 7 20 7 11 3 8 Calibrate External Current Programming Voltage Reading Gain cecceeseeeneeeteeteneeteneeteaees 7 21 7 11 4 Calibrate Specific Interface Commandes 7 21 APPENDIX A GLOSSARY OF TERMINOLOGY cccssesseeeeseeeeseeeeeeeeaseeensneeaseeenseeeaseeeasaneaseeeasaeeaseeeeseeesseenseeeeeeeeas A 1 APPENDIX B UNITS FOR MAGNETIC PROPERTIES ccssccsseecseeeeeseeeeeneeneeeeneeaenseeeaseaeaseeeaseasaseeeaseaeaeeeeaseeseeeees B 1 viii Table of Contents Lake Shore Model 642 Electromagnet Power Supply User s Manual Figure No 1 1 2 1 2 2 2 3 2 4 2 5 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 3 10 3 11 3 12 3 13 3 14 3
172. ss and hold the Status key on the front panel until the display goes dark 3 seconds When the key is then released a diagnostics display will be seen The upper right reading EXT PROG is the reading needed for this step 4 Calculate zero offset constant external programming voltage reading 5 Send CALZ 7 zero offset constant 6 Verify the Model 642 external programming voltage reading to be 0 0 0001 V 7 Send CALSAVE to write this calibration to non volatile memory 7 11 3 5 Calibrate Output Current Gain Span This calibration is the most difficult and most important of the procedure It first requires measuring the span of the trim range which changes from unit to unit within 1 2 to determine the trim adjustment range that corresponds to a 100 calibration trim change In other words we adjust the calibration in from 100 to 100 but the size of the calibration trim range changes slightly for each unit We first measure the span of the calibration trim range and then measure the full span of the instrument with the calibration trim set to 0 We have adopted the use of as the unit name for the trim calibration since it corresponds to only the percent of trim range and not the full span of the instrument The 65 A set point for calibration is chosen because the maximum trim range at 70 A forces the current past the 70 1 A internal analog limit and therefore creates significant error The shunt
173. st hardware line on the bus 5 4 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual Standard Event Status Register ESR Bit Name Standard Event 7 J e s 4 3 2 7 0 Status Enable ESE ESE PON Power on CME Command Error EXE Execution Error QYE Query Error Output OPC Operation Complete Buffer Status Byte 7 T 6 Ts Je pspepifojar egister N N STB Used HESB OESB Uses Name Generate service AND RQS request Reset by serial poll AND MSS Read by STB SE 7 6e s 4 3 2 1 0 Bi nabile Register Not Not SC SRE SRE MAV Used HESB OESB usea Name OSB Operation Summary Bit RQS Service Request MSS Master Summary Status Bit ESB Event Status Sumary Bit MAV Message Available Summary Bit HESB Hardware Error Summary Bit OESB Operational Error Summary Bit Operation Condition 7 6 5 4 3 2 fo bt Operation Ee deca Event 7 6 5 4 3 2 14 0 Bit Register Not Not Not Not Not opstne dis PRIM RAV conP Name AND AND AND 7 Iesst COMP Operation Event Enable Register Not Not Not Not OPSTE Used Used PRLM RAMP OPSTE PRLM Power Limit RAMP Ramp Done COMP Compliance Figure 5 1 Model 642 Status System Sheet 1 of 2
174. t ERSTR reads and clears the Error Status Register The used bits of the Error Status Event Register are described as follows Remote Enable Fault Detected REF Bit 7 This bit is set if a fault condition is detected on the remote enable interlock Power Supply Flow Switch Fault Detected PFF Bit 6 This bit is set if a fault condition is detected on the power supply flow switch interlock Magnet Flow Switch Fault Detected MFF Bit 5 This bit is set if a fault condition is detected on the magnet flow switch interlock High Line Voltage HLV Bit 4 This bit is set if the power line voltage exceeds an acceptable amplitude Operation can continue but additional heat may be dissipated by the instrument Low Line Voltage LLV Bit 3 This bit is set if the power line voltage drops below an acceptable amplitude Operation can continue but output voltage may not reach maximum specification Temperature High OOV Bit 2 This bit is set if the internal temperature of the instrument exceeded 40 C The output current will be set to zero and will not be settable until the fault is cleared External Current Program Error EPE Bit 1 This bit is set if the instrument cannot go into external or sum current programming modes because the programming voltage is too high The output current will be set to zero and will not be settable until the fault is cleared Calibration Error CAL Bit 0 This bit is
175. t power off and on again before CALSAVE is issued to restore the old calibration constants Once CALSAVE is issued old values cannot be retrieved from the instrument If calibration coefficients are left at default or are outside of the normal calibration range the following error message will appear in the instrument display when the instrument is turned on Calibration Invalid This error message must be bypassed to allow calibration of the instrument Press both Enter and Escape keys simultaneously to bypass the error message Operation in this state is possible but at least one calibration is known to be out of proper range and measurement is likely to be erroneous Simple communications program examples are shown in Sections 5 1 5 2 and 5 2 7 1 Some time should be spent becoming familiar with the calibration commands before beginning a calibration Although the calibration factors are sent to the Model 642 over the computer interface this procedure is written to obtain the Model 642 readings solely by visual observation of the front panel 7 16 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 11 2 Calibration Equipment 1 Calibration Shunt Resistor The output current of the Model 642 must be measured externally as the primary reference for calibration When current is measured it is the result of the current through the known resistance of the calibration resistor This resistor must be accurately
176. t pressure through varying material thickness due to heating The magnet leads should be dressed straight down to allow the installation of the protective lug cover Lug cover installation is shown in Figure 3 14 Table 3 3 Current Capacity and Total Lead Lengths AWG Area Capacity Resistivity Distance to Magnet mm A 421000 feet Max Output of 70 A 0 53 5 245 0 09827 22 M 72 ft 2 33 6 180 0 1563 14 M 45ft 4 21 2 135 0 2485 8 5 M 28 ft 6 13 3 100 0 3951 5 5 M 18 ft 8 8 4 75 0 6282 3 4M 11 ft Installation 3 9 Lake Shore Model 642 Electromagnet Power Supply User s Manual NN D CH Y i d f J BOLT NUT BELLEVILLE WASHER PLAIN WASHER A OUTPUT LUG d MAGNET CABLE Figure 3 13 Output Cable Connection yt AT e e i9 d LUG COVER 38 mm 1 5 in MOUNTING SCREWS Figure 3 14 Output Lug Cover Installation 3 10 Installation Lake Shore Model 642 Electromagnet Power Supply User s Manual 3 9 ANALOG INPUT OUTPUT CONNECTIONS The Analog I O connector provides connections to analog signals used to monitor or control the power supply A Current Program input is provided to control the current output Two outputs are also provided to monitor the output current and the output voltage The connector and pin out table is shown in figure 3 15 Specific information on each function is provided in paragraphs 3 9 1 and 3 9 2 1 5 e 8 a GI
177. ta Z 10 centi c 10 8 exa E 107 milli m 10 peta P 10 micro u 10 tera T 10 nano n 10 giga G 10 pico p 10 mega M 10 femto f 10 kilo k 1078 atto a 10 hecto h 107 zepto Z 10 deka da 10 yocto y probe A long thin body containing a sensing element which can be inserted into a system in order to make measurements Typically the measurement is localized to the region near the tip of the probe proportional integral derivative PID A control function where output is related to the error signal in three ways Proportional gain acts on the instantaneous error as a multiplier Integral reset acts on the area of error with respect to time and can eliminate control offset or droop Derivative rate acts on the rate of change in error to dampen the system reducing overshoot rack mount An instrument is rack mountable when it has permanent or detachable brackets that allow it to be securely mounted in an instrument rack The standard rack mount is 19 inches wide A full rack instrument requires the entire width of the rack Two half rack instruments fit horizontally in one rack width relief valve A type of pressure relief device which is designed to relieve excessive pressure and to reclose and reseal to prevent further flow of gas from the cylinder after reseating pressure has been achieved remanence The remaining magnetic induction in a magnetic material when the material is first saturated and then the applied field is reduced to
178. te Ramp segments Operation Protection 0 1 mA 20 bit 600 ms for 1 step to within 1 mA of internal setting 10 mA 0 05 of setting Keypad computer interface Programmable current setting limit 0 1 mA s to 99 999 A s compliance limited 23 7 increments s 5 Keypad computer interface Programmable ramp rate limit External current programming Sensitivity Resolution Accuracy Input resistance Operation Limits Connector Readings Output current Resolution Accuracy Update rate 10 V 70 A Analog 10 mA 1 of setting 20 KQ Voltage program through rear panel can be summed with internal current setting Internally clamped at 10 1 V and bandwidth limited at 40 Hz to protect output Shared 15 pin D sub 0 1 mA 5 mA 0 05 of rdg 2 5 rdg s display 10 rdg s interface Output voltage at supply terminals Resolution Accuracy Update rate Front panel Display type Display readings Display settings Display annunciators LED annunciators Audible annunciator Keypad type Keypad functions Power ImV 5 mV 0 05 of rdg 2 5 rdg s display 5 rdg s interface 8 line by 40 character graphic vacuum fluorescent display module Output current output voltage and internal water temperature Output current and ramp rate Status and errors Fault Compliance Power Limit Ramping Remote Errors and faults 26 full travel keys Direct access to common operations menu driven setup White flus
179. terface Program Public gSend As Boolean Global used for Send button state Private Sub cmdSend Click gSend True End Sub Routine to handle Send button press Set Flag to True Private Sub Form Load Dim strReturn As String Dim strHold As String Dim Term As String Dim ZeroCount As Integer Dim strCommand As String frmSerial Show Term Chr 13 amp Chr 10 ZeroCount 0 strReturn strHold vn True Then False If frmSerial MSComml PortOpen frmSerial MSComm1 PortOpen End If frmSerial MSComm1 CommPort frmSerial MSComml Settings frmSerial MSComm1 InputLen frmSerial MSComm1 PortOpen 1 9600 0 7 1 1 True Do Do DoEvents Loop Until gSend gSend False True frmSerial txtCommand Text nu strCommand strReturn strCommand UCase strCommand If strCommand EXIT Then End End If frmSerial MSComm1 Output strCommand amp Term If InStr strCommand lt gt 0 Then While ZeroCount lt 20 And strHold lt gt Chr 10 If frmSerial MSComml InBufferCount 0 Then frmSerial Timerl Enabled True Do DoEvents Loop Until frmSerial Timerl Enabled ZeroCount ZeroCount 1 Else ZeroCount 0 strHold frmSerial MSComml1 Input strReturn strReturn strHold End If Wend If strReturn lt gt Then strReturn Mid strReturn 1 InStr strReturn Else strReturn No Response End If frmSerial txtResponse Text strReturn strHold vn ZeroCount 0 End
180. tes the operation that was initiated by the command sequence Once the sequence is complete a 1 will be placed in the output buffer Refer to Paragraph 5 1 4 4 6 for more information RST Reset Instrument Command Input RST term Remarks Sets controller parameters to power up settings Use the DFLT command to set factory defaults 5 30 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual SRE Input Format Remarks SRE Input Returned Format STB Input Returned Format Remarks TST Input Returned Format Remarks WAT Input Remarks BAUD Input Format BAUD Input Returned Format Service Request Enable Register Command SRE lt bit weighting gt term nnn The Service Request Enable Register determines which summary bits of the Status Byte may set bit 6 RQS MSS of the Status Byte to generate a Service Request This command programs the enable register using a decimal value that corresponds to the binary weighted sum of all bits in the register Refer to Paragraph 5 1 4 4 Service Request Enable Register Query SRE term lt bit weighting gt term nnn Refer to command for description Status Byte Query STB term lt bit weighting gt term nnn This command is similar to a Serial Poll except it is processed like any other instrument command It returns the same result as a Serial Poll except that t
181. th 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 against damage during shipment but a timely claim must be filed before Lake Shore will take further action Procedures vary slightly with shipping companies Keep all shipping materials and damaged contents until instructed to either return or discard them If the instrument must be returned for recalibration replacement or repair a returned goods authorization RA number must be obtained from a factory representative prior to return The Lake Shore RA procedure is given in Paragraph 7 2 Items Included with Model 642 Electromagnet Power Supply 1 Model 642 Instrument 1 Model 642 User s Manual 2 Front Handles shipped attached 2 Rear Handles shipped attached 1 Analog I O Mating Connector 1 Output Terminal Fasteners set 1 Wiring Cover Plate and Screws 2 4 Pin Detachable Terminal Blocks 1 8 Pin Detachable Terminal Block 2 Hose Clamps 1 Output Lug Cover and Screws 3 1 1 Moving and Handling Four handles are provided for ease of moving and handling the Model 642 The handles can be used in place of lifting lugs when cloth straps are used Always use all four handles when moving the Model 642 Because of its weight the Model 642 should be handled by mechanical means If for some reason it is necessary t
182. the low voltage and the electromagnetic compatibility EMC directive Instrument users have come to rely on Lake Shore equipment for convenience and ease of use The Model 642 includes features such as built in current and power limits internal cooling water and magnet water control to minimize condensation current ramping and the capability to modulate the output current Computer interfaces are also integrated for automation of the magnet system The Model 642 is truly an excellent one box solution for controlling an electromagnet Output Architecture True 4 quadrant output capability of the Model 642 is ideal for the charge and discharge cycling of electromagnets for both positive and negative fields Tightly integrated analog control of the 4 quadrant output provides smooth current change with very low overshoot on output change The Model 642 has the ability to charge and discharge magnets up to a 50 A per second rate into a nominal 0 5 Q 0 5 H load True 4 quadrant operation eliminates the need for external switching or operator intervention to reverse the current polarity significantly simplifying system operation The transition through zero current is smooth and continuous allowing the user to readily control the magnetic field as polarity changes At static fields output current drift is also kept low by careful attention in the analog control circuits and layout The high stability and low noise of the Model 642 provides a quiet and
183. ting correctly refer to Paragraph 5 1 5 1 Use the following procedure to develop the TEEE 488 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 CommandButton control to the form 6 Onthe View Menu select Properties Window 7 Inthe Properties window use the dropdown list to select between the different controls of the current project 10 Set the properties of the controls as defined in Table 5 4 11 Save the program 5 16 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual Table 5 4 IEEE 488 Interface Program Control Properties Current Name Property New Value Labell Name IbIExitProgram Caption Type exit to end program Label2 Name lblCommand Caption Command Label3 Name IbIResponse Caption Response Textl Name txtCommand Text lt blank gt Text2 Name txtResponse Text lt blank gt Command1 Name cmdSend Caption Send Default True Form Name From IEEE 488 Caption IEEE 488 Interface Program 12 Add code provided in Table 5 5 a In the Code Editor window under
184. to monitor the output current and voltage Each output is a buffered differential analog voltage representation of the signal being monitored The current monitor has a sensitivity of 7 V 70 A while the voltage monitor has a sensitivity of 3 5 V 35 V Display and Keypad The Model 642 incorporates a large 8 line by 40 character vacuum fluorescent display Output current and output voltage readings are displayed simultaneously Five LEDs on the front panel provide quick verification of instrument status including ramping power limit compliance fault and computer interface mode Error conditions are indicated on the main display along with an audible tone Extended error descriptions are available in an error message screen by pressing the Status key The keypad is arranged logically to separate the different functions of the instrument The most common functions of the power supply are accessed using a single key press The keypad can be locked to either lock out all changes or to lock out just the instrument setup parameters allowing the output of the power supply to be changed 1 2 SPECIFICATIONS Output Type Current generation Current range Compliance voltage DC Power Nominal load Maximum load resistance Minimum load resistance Load inductance range Current ripple Current ripple frequency Temperature coefficient Line regulation Stability 1 h gt Stability 24 h Isolation Slew rate Compliance voltage AC Se
185. to protect the Model 642 from loss of water flow Pins 1 amp 2 must be closed for normal operation Pins 3 amp 4 supply 24 VAC at 1 A for operation of a water control valve FLOW SWITCH WATER VALVE 4 POWER SUPPLY Name 1 Flow Switch Com 2 Flow Switch 3 Power Supply Water Valve A 4 Power Supply Water Valve B Figure 7 10 Power Supply Connector Details 7 10 5 RS 232C Serial Interface Connector This connector provides one of two means of computer interface Command descriptions are found in Section 5 1 6 Di E e N ise Cd N a gt g Model 642 Electromagnet Power Supply Typical Computers DE 9P DTE DB 25P DTE DE 9P DTE Pin Description Pin Description Pin Description 1 NC 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 Chassis common 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 DCD in 7 RTS out 8 NC 20 DTR out 8 CTS in 9 NC 22 Ring in in 9 Ring in in Figure 7 11 RS232C DTE Connector Details Service 7 13 Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 10 6 Serial Interface Cable Wiring The following are suggested cable wiring diagrams for
186. top Parity Odd Terminators CR ODH LF OAH Command Rate 20 commands per second maximum 5 2 5 Message Strings A message string is a group of characters assembled to perform an interface function There are three types of message strings commands queries and responses The computer issues command and query strings through user programs the instrument issues responses Two or more command or query strings can be chained together in one communication but they must be separated by a semi colon The total communication string must not exceed 255 characters in length A command string is issued by the computer and instructs the instrument to perform a function or change a parameter setting The format is lt command mnemonic gt lt space gt lt parameter data gt lt terminators gt Command mnemonics and parameter data necessary for each one is described in Paragraph 5 3 Terminators must be sent with every message string 5 22 Computer Interface Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual Message Strings Continued A query string is issued by the computer and instructs the instrument to send a response The query format is lt query mnemonic gt lt gt lt space gt lt parameter data gt lt terminators gt Query mnemonics are often the same as commands with the addition of a question mark Parameter data is often unnecessary when sending queries Query mnemonics and parameter data if necess
187. tput current ramp rate This value will be used in both the positive and negative directions Setting value is limited by LIMIT Output Current Ramp Rate Setting Query RATE term lt rate gt term n nnnn Refer to command for description Current Output Reading Query RDGI term lt current gt term nn nnnn lt current gt Actual measured output current Computer Interface Operation 5 35 Lake Shore Model 642 Electromagnet Power Supply User s Manual RDGV Output Voltage Reading Query Input RDGV term Returned lt voltage gt term Format n nnnn lt voltage gt Actual output voltage measured at the power supply terminals RSEG Ramp Segments Enable Command Input RSEG lt enable gt term Format n term lt enable gt Specifies if ramp segments are to be used 0 Disabled 1 Enabled Remarks Ramp segments are used to change the output current ramp rate based on the output current Ramp segments need to be setup first using the RSEGS command RSEG Ramp Segments Enable Query Input RSEG term Returned lt enable gt term Format n Refer to command for description RSEGS Ramp Segments Parameters Command Input RSEGS lt segment gt lt current gt lt rate gt term Format n nn nnnn n nnnn term lt segment gt Specifies the ramp segment to be modified 1 5 lt current gt Specifies the upper output current setting that will use this segment 0 0000 70 1000A lt rate
188. ttling time Modulation response Attenuation Protection Connector Bipolar 4 quadrant DC current source Fully linear regulation with digital setting and analog control 70 A 35 V nominal 2450 W nominal 0 5 Q 0 5 H 0 6 Q for 70 A DC operation at 10 to 5 line voltage 0 4 Q for 70 A at 5 to 10 line voltage 0Hto1H 5 mA RMS 0 007 at 70 A into nominal load Dominated by the line frequency and its harmonics 15 ppm of full scale C 60 ppm of full scale 10 line change 1 mA h after warm up 5 mA 24 h typical dominated by temperature coefficient and line regulation Differential output is optically isolated from chassis to prevent ground loops 50 A s into nominal load 650 A s maximum into a resistive load 43 V at 10 to 5 line lt 1 s for 10 step to within 1 mA of output into nominal load lt 0 17 Hz at 70 A sine wave into nominal load lt 0 02 THD lt 10 Hz at 10 A sine wave into nominal load lt 0 10 THD 0 5 dB at 10 Hz Short circuit line loss low line voltage high line voltage output over voltage output over current and over temperature Two lugs with 6 4 mm 0 25 in holes for M6 or 0 25 in bolts Introduction Lake Shore Model 642 Electromagnet Power Supply User s Manual Specifications Continued Output programming Internal current setting Resolution Settling time Accuracy Operation Protection Internal current ramp Ramp rate Update ra
189. ument The cable has 24 conductors with an outer shield The connectors are 24 way Amphenol 57 Series or equivalent with piggyback receptacles to allow daisy chaining in multiple device systems The connectors are secured in the receptacles by two captive locking screws with metric threads The total length of cable allowed in a system is 2 meters for each device on the bus or 20 meters maximum The Model 642 can drive a bus of up to 10 devices A connector extender is required to use the IEEE 488 Interface and Relay Terminal Block at the same time Figure 7 12 shows the IEEE 488 Interface connector pin and signal names as viewed from the Model 642 rear panel 7 14 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual 1 13 Lu O lt LC oc Lu E zZ co Y LU LL Lu 12 24 Pin Symbol Description 1 DIO1 Data Input Output Line 1 2 DIO2 Data Input Output Line 2 3 DIO3 Data Input Output Line 3 4 DIO4 Data Input Output Line 4 5 EOI End Or Identify 6 DAV Data Valid 7 NRFD Not Ready For Data 8 NDAC Not Data Accepted H IFC Interface Clear 10 SRQ Service Request 11 ATN Attention 12 SHIELD Cable Shield 13 DIOS Data Input Output Line 5 14 DIO6 Data Input Output Line 6 15 DIO7 Data Input Output Line 7 16 DIO8 Data Input Output Line 8 17 REN Remote Enable 18 GND6 Ground Wire Twisted pair with DAV 19 GND7 Ground Wire Twisted pair with NRFD 20 GND8 Ground Wire Twiste
190. up Escape Fault 7 8 9 External Computer Program Interface Remote Compliance 4 5 6 A Ramp Max Segments Settings Status Power Limit 1 2 3 V Ramping Output Setting Figure 4 2 Model 642 Keypad and LED Layout Table 4 2 Model 642 Key Descriptions Magnet Water Selects the magnet water setup menu Refer to Paragraph 4 12 Internal Water Selects the internal water setup menu Refer to Paragraph 4 13 Display Setup Sets the display brightness Refer to Paragraph 4 5 Exits from parameter setting sequence without changing the parameter value Press and hold to Escape reset parameters to default values Refer to Paragraph 4 18 External Program Setup the external current programming mode Refer to Paragraph 4 15 Computer Interface Setup RS 232C and IEEE 488 computer interfaces Refer to Paragraph 4 17 Ramp Segments Setup ramp segment values Refer to Paragraph 4 8 Max Settings Setup maximum setting limits for output current and ramp rate Refer to Paragraph 4 11 Status Displays a summary of the instrument status Refer to Paragraph 4 14 Enter Accepts a new parameter value Press and hold to lock keypad Refer to Paragraph 4 16 0 9 Numeric data entry within a setting sequence Up Increments a parameter selection or value Down Decrements a parameter selection or value Output Setting Sets the output current Refer to Paragrap
191. ut Lug Cover Installation viciosa ni a a Zei 3 10 Analog Input Output Gonnector dees Rda ia 3 11 Mounting Hole GC EE 3 12 Model 642 Power Push Buttons AAA 4 1 Model 642 Keypad and LED Layout eee esseeeeeeneeeeseeeeeeeeeeeeeeaeeeeesaeeeeseneeeeesaeeeteaeeeeseneeeeeeeeerenaeees 4 3 Model 642 Status System enge heres cei Mei eege Eed oie oi lea 5 5 Standard Event Status EE E 5 8 Operation Event Register lat lali davai ae 5 9 Hardware Error Status Register caca cdi dret ibid 5 10 Operational Error Status Register acicate dada ads 5 11 Status Byte Register and Service Request Enable Register A 5 12 GPIBO Setting Bei ils E le TEE 5 15 DEV 12 Device Template Configuration oooconccinnicinnnonncccnonncnnnncnonncnnncc nono narrar rn rar 5 15 Typical National Instruments GPIB Configuration from IBCONF ENEE 5 19 Model 642 Rear ET EE 7 2 Voltage COMIDA daa 7 3 Eller 7 4 Fuse Holder Detalla A ee es eo Mi ee 7 5 Board Locations E A A A E R 7 9 Digital Board Parts Location Ssi e EES cones lle Mga SOERENSEN Bixee reece aatal 7 10 Analog UO Connector Details ecceeecceeeeeeeseeeeeeeeeneeeeeeeeeseeeseneeeaeeeseeeeeaeeesaeeeeaeeesaeeeeeeeseeesneeeseeeseneeess 7 11 Magnet Gonnector Detalls s inon ah a here ee Heh dada 7 11 Auxiliary Connector Detail cion ita tdt haan 7 12 Power Supply Connector Detallada Alar 7 13 RS 2326 DT E Connector Details ide EEN deeg 7 13 EEE 488 Connector DetallS ccoo AD daa 7 15 Table of Contents
192. uter for automated control or data taking Refer to Chapter 5 4 17 1 Changing Serial Baud Rate To select the Serial Interface Baud Rate press the Computer Interface key The first computer interface screen appears as a prompt for Baud Use the A or Y key to select 9600 19200 38400 or 57600 Baud Default is 9600 Baud Press Enter to accept the new selection and continue to the next screen Press Escape to cancel the new selection and return to the normal display 4 10 Operation Lake Shore Model 642 Electromagnet Power Supply User s Manual 4 17 2 Changing IEEE 488 Interface Parameters Two interface parameters address and terminators must be set from the front panel before IEEE 488 communication with the instrument can be established Other interface parameters can be set via the interface using the device specific commands provided in Paragraph 5 3 To set the IEEE 488 parameters press the Computer Interface key and press Enter to skip past Serial Interface Baud Rate The following computer interface screen appears as a prompt for the IEEE 488 address Use the A or Y key to select an address between 1 and 30 The default is twelve 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 computer interface screen appears as a prompt for the IEEE 488 terminators Use the A or Y
193. wer electrical connections to the rear of the Model 642 are detailed in this section 7 10 1 Analog UO Connector The Analog I O connector provides the connections for the External Programming voltage as well as Analog representations of the current and voltage output levels Although these inputs outputs are electronically balanced to minimize ground loops the common mode voltage should not exceed 5 V on the outputs and 2 V on the input fe 15 DA 3 e WA O PERK Es z lt 3 1 Pin Name Pin Name 1 NC 9 NC 2 Chassis common 10 Chassis common 3 Current Program 11 Current Program 4 Chassis common 12 Chassis common 5 Voltage Monitor 13 Voltage Monitor 6 Chassis common 14 Chassis common 7 Current Monitor 15 Current Monitor 8 Chassis common Figure 7 7 ANALOG I O Connector Details 7 10 2 Magnet Connector The Magnet Water connector provides the means to connect a water control valve 24 VAC and an associated water flow switch closed during flow to protect the magnet from loss of water flow Pins 1 amp 2 must be closed for normal operation Pins 3 amp 4 supply 24 VAC at 1 A for operation of a water control valve 1 FLOW Er SWITCH Ww d WATER VALVE 4 Pin Name 1 Flow Switch Com 2 Flow Switch 3 Magnet Water Valve A 4 Magnet Water Valve B Figure 7 8 Magnet Connector Details Service 7 11 Lake Shore Model 642 Electromagnet Power Suppl
194. will only limit the internal output current ramp setting If ramp segments are being used this setting will also limit the ramp rate that can be set by aramp segment Refer to Paragraph 4 8 to setup Ramp Segments To enter a value for the maximum current ramp rate limit continue from the maximum current screen or press Max Settings then Enter until the following display setup screen appears as a prompt for the maximum current ramp rate limit Use the data entry keys to enter the maximum current ramp rate limit value between 0 0001 and 99 999 A s Press Enter to accept the new value Press Escape to restart the setting sequence and enter a different value Press Escape again to leave the setting sequence Operation 4 7 Lake Shore Model 642 Electromagnet Power Supply User s Manual 4 12 MAGNET WATER The Model 642 provides power to control an external magnet water solenoid control valve The setup of the valve control is available in the Magnet Water menu The four menu selections are Auto On Off and Disabled with Auto being the default setting In the Auto mode the water valve will be energized when the power in the magnet exceeds 100 W When the power drops below 100 W the valve will remain energized for an additional minute to remove any residual heat build up In the On mode the valve will be energized whenever the power supply is on This feature can be used when the system is first installed to purge air fro
195. y Computer interface instructions are in Chapter 5 4 1 TURNING POWER ON Verify that the AC line voltage indicator on the rear panel of the unit shows the appropriate AC line voltage before turning the instrument on The instrument may be damaged if it is turned on with the incorrect voltage selected Instructions for checking line voltage selection are given in Paragraph 3 3 1 CAUTION Be sure the unit is connected to an appropriate load before applying power Note The Model 642 will not turn on if an Emergency Stop Switch is not connected or a jumper is not put in its place on the Auxiliary connector at the rear of the unit The unit will not turn on if it is connected to a voltage source more than 10 greater than the voltage for which it is configured The power ON and OFF buttons are located in the lower left corner of the front panel Press the ON button to energize the Model 642 The Model 642 can be de energized by pressing the OFF button by pressing an optional remote Emergency Stop button or by the Model 642 software when a hazardous fault condition is detected The ON and OFF buttons are illustrated in Figure 4 1 S wer POWER ON BUTTON 7 POWER OFF BUTTON Figure 4 1 Model 642 Power Push Buttons When the Model 642 is turned on the display shows the Lake Shore logo and the alarm beeper sounds briefly After a few seconds a Checking Hardware message will appear in the center of the logo display while the i
196. y User s Manual 7 10 3 Auxiliary Connector The Auxiliary Connector provides connections for three functions 1 Emergency Stop This normally closed circuit turns off power to the Model 642 just as if the OFF O button was pressed on the front panel when opened Normal operation requires a closed connection between the pins Fault Relay The fault relay can be used to communicate the presence of a Model 642 fault to external equipment The relay follows the operation of the Fault light on the front panel Both normally open and normally closed configurations are provided The contacts are electrically isolated from the Model 642 chassis Remote Enable These contacts are similar in function to the flow switch inputs Normal enabled operation requires a closed connection between the pins EMERGENCY E 5 STOP J o CHASSIS In FAULTNO In FAULTCOM FAULTNC o REMOTE Jo ENABLE CH a AUXILIARY Pin Name Emergency Stop A Emergency Stop B 1 2 3 Chassis common 4 Fault NO 5 6 7 Fault Com Fault NC Chassis common 8 Remote Enable Figure 7 9 Auxiliary Connector Details 7 12 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 10 4 Power Supply Connector The Power Supply connector provides the means to connect a water control valve 24 VAC and an associated water flow switch closed during flow
197. y at your own risk Some countries states and provinces do not allow the exclusion of liability for incidental or consequential damages so the above limitation may not apply to you LIMITED WARRANTY STATEMENT Continued 9 EXCEPT TO THE EXTENT ALLOWED BY APPLICABLE LAW THE TERMS OF THIS LIMITED WARRANTY STATEMENT DO NOT EXCLUDE RESTRICT OR MODIFY AND ARE IN ADDITION TO THE MANDATORY STATUTORY RIGHTS APPLICABLE TO THE SALE OF THE PRODUCT TO YOU CERTIFICATION Lake Shore certifies that this product has been inspected and tested in accordance with its published 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 642 firmware is as free of errors as possible and that the results you obtain from the instrument are accurate and reliable However as with any computer based software the possibility of errors exists In any important research as when using any laboratory equipment results should be carefully examined and rechecked before final conclusions are drawn Neither Lake Shore nor anyone else involved in the creation or production of this firmware can pay for loss of time inconvenience loss of use of t
198. ystals during testing handling repair or assembly Discharge voltages below 4000 volts cannot be seen felt or heard 7 7 1 Identification of Electrostatic Discharge Sensitive Components The following are various industry symbols used to label components as ESDS nO d CAUTION A A 69 ESD SENSITIVE DEVICE 7 6 Service Lake Shore Model 642 Electromagnet Power Supply User s Manual 7 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 surface and discharge paths As a minimum observe these precautions De energize or disconnect all power and signal sources and loads used with unit 2 Place unit on a grounded conductive work surface 3 Ground the technician through a conductive wrist strap or other device using 1 MQ series resistor to protect operator 4 Ground any tools such as soldering equipment that will contact unit Contact with operator s hands provides a sufficient ground for tools that are otherwise electrically isolated 5 Place ESDS devices and assemblies removed from a unit on a conductive work 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 plasti

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