Model No. 120CS - Lake Shore Cryotronics, Inc.
Contents
1. connection in Paragraph 2 4 sensor installation recommendations in Paragraph 2 5 and rack mounting in Paragraph 2 6 24 INSPECTION AND UNPACKING Inspect shipping containers for external damage Make all claims for damage apparent or concealed or partial loss of shipment in writing to Lake Shore within five 5 days from receipt of goods If damage or loss is apparent please notify the shipping agent immediately Open the shipping containers Use the packing list included with the system to verify receipt of the instrument sensor accessories and manual Inspect for damage Inventory all components supplied before discarding any shipping materials If there is freight damage to the instrument file proper claims promptly with the carrier and insurance company and notify Lake Shore Notify Lake Shore immediately of any missing parts Lake Shore cannot be responsible for any missing parts unless notified within 60 days of shipment Refer to the standard Lake Shore Warranty on the A Page immediately behind the title page 22 REPACKAGING FOR SHIPMENT To return the Model 120CS or accessories for repair or replacement obtain a Return Goods Authorization RGA number from Technical Service in the United States or from the authorized sales service representative from which the product was purchased Instruments may not be accepted without a RGA number When returning an instrument for service Lake Shore must have the following inform2. User s Manual Model 120CS Current Source EL akeShore Lake Shore Cryotronics Inc 575 McCorkle Boulevard Westerville Ohio 43082 8888 USA Internet Addresses salesQ lakeshore com service lakeshore com Internet Addresses wwwlakeshore com Fax 614 891 1392 Telephone 614 891 2243 Methods and apparatus discosed and described herein have bean developed solely on company funds of Lake Shore Cryotronice Inc No government or other contractual support or relationship whatsoever has usted which ih any way afiect or mitigates proprietary gts of Lara Shore Cryotronies Inc in hess developments Methods and apparatus closed heran may be subject sting or applied for Lake Shore Cryotronics Inc reserves tha ight lo add fy or withdraw functions design modifications or products a any time without Shore shall not be Babie for eror contained herein or or ncidental or consequenti damages in connection with fumshing perfomance or use of this material Rev 1 3 PIN 119 016 3 December 2004 Lake Shore Model 120CS User s Manual LIMITED WARRANTY STATEMENT WARRANTY PERIOD ONE 1 YEAR 1 Lake Shore warrants that this Lake Shore prodot be rodoc wil be Boc fum dels materi sd workmanship R the Warranty Ped specified abone e Warranty Period I Lake Shore receives lc ofany such defects duin e Warranty Period ad he Product hip freight prepaid Lake Shire il tks option eer ea s replace he Prodat if
3. 24 Load Connection 22 25 Sensor Installation Recommendations 22 254 Connecting Sensor Leads 23 252 Sensor Mounting 23 253 Measurement Errors Due To AC Noise 24 26 Rack Mounting 2 5 3 OPERATION 30 General 34 34 Front Panel Features and Functions 3 4 32 Rear Panel Features and Functions 32 33 Selecting Output Current Value Fixed Ranges 3 2 34 Program Mode 33 4 40 General 44 44 Fuse Replacement 44 42 Line Voltage Configuration 44 43 10 pA Current Calibration 42 m PRGM Mode Calibration 43 444 Current Calibration Using DC Amp Range 43 442 Current Calibration Using DC Volt Range 44 Table of Contents Lake Shore Model 120CS User s Manual Figure 24 22 44 Table 4 3 4 LIST OF ILLUSTRATIONS Title Model 2090 Rack Mounting Model 120CS Front Panel Model 120CS Rear Panel Fuse Replacement and Jumper Configurations LIST OF TABLES Title Model 120CS Specifications Output Currents and Corresponding 1 Resistances Page 2 6 22 42 Page 12 ES Table of Contents Lake Shore Model 120CS User s Manual CHAPTER 1 INTRODUCTION 10 GENERAL Lake Shore Cryotronics Inc designed and manufactures the Model 120CS in the USA A general description of the instrument is provided in Paragraph 1 1 handling liquid helium and nitrogen in Paragraph 1 2 electrostatic discharge in Paragraph 1 3 safety summary in Paragraph 1 4 and safety symbols in Paragraph 1 5 We welcome comments on this manual
4. Although we try to keep it error free some may occur To report an error describe it briefly and include the appropriate paragraph figure table and page number Send comments to Lake Shore Cryotronics Attn Technical Publications 575 McCorkle Blvd Westerville Ohio 43082 8888 This manual is subject to change without notice 11 GENERAL DESCRIPTION The Model 120CS is an ideal current source for quick accurate stable outputs for sensor excitation or other applications Compliance voltage of 11 volts assures constant current under a wide range of load conditions The instrument features 1 pA to 100 mA Output Current Front panel OUTPUT switch to easily reverse polarity Red CMPL light to alert user when compliance limit is reached Capability for external resistor programming from 1 pA to 100 mA Selectable output current in 1X and 3X increments The Model 120CS has a compliance voltage of 11 Volts allowing it to be used as an excitation source in a variety of diode sensor applications It also features a compliance LED visually indicates the unit is operating within specification Introduction 44 Lake Shore Model 120CS User s Manual Table 1 1 Model 120CS Specifications Output Current 11 fixed ranges from 1 pA to 100 mA front panel selection in 1X and 3X increments Rear panel PRGM allows external resistor programming throughout range 1 pA to 100 mA Accuracy 0 1 on fixed ranges fa
5. 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 crystals during testing handling repair or assembly Discharge voltages below 4000 volts cannot be seen fell or heard 14 Introduction Lake Shore Model 120CS User s Manual 13 1 Identifying ESDS Components Below are some industry symbols used to label components as ESDS Q GO de 1 3 2 Handling ESDS Components Observe all precautions necessary to prevent damage to ESDS components before installation Bring the device and everything that contacts it to ground potential by providing a conductive surface and discharge paths At a minimum observe these precautions 1 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 technician through a conductive wrist strap or other device using 1 MO 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 Us
6. CHAPTER 3 OPERATION 3 0 GENERAL This chapter describes front panel features and functions in Paragraph 3 1 rear panel features and functions in Paragraph 3 2 instructions for selecting output current value fixed ranges are provided in Paragraph 3 3 and program mode is discussed in Paragraph 3 4 3 4 FRONT PANEL FEATURES AND FUNCTIONS POWEI OUTPUT Three Position Toggle Switch selects output current polarity defined as follows Norm Current supplied out of OUT terminal Off Output current is zero Revrs Current supplied out of OUT terminal ush to turn power to unit On Push again to turn power Off Current Selector Switch 12 position rotary switch selects one of 11 fixed internal current values and one programmable value Select one of the 11 Fixed Ranges in 1X and 3X increments from 1 pA to 100 mA Select PRGM and connect a resistor across the PRGM terminals on the rear panel to set output current CMPL COMPLIANCE LED illuminates when the OUTPUT switch is set to NORM or REVRS and output vollage is zero to less than 11 volts Compliance voltage is the maximum voltage that can be developed across the output terminals while maintaining the specified output current If output current reaches 11 volts the light flashes ON LED Illuminates when power to unit is On ElLakeShore 120 Current Source OUTPUT POWER Nom E O80 of e Figure 3 1 Model 120CS Front Pa
7. PRGM ADJ trimmer until DVM reads 1 0000 volt Resume normal operation 44 Service NOTES Lake Shore is a technology leader in the development of cryogenic temperature sensors precision low temperature measurement and control instrumentation and magnetic measurement and test systems Since 1968 Lake Shore physicists material scientists and engineers have dedicated themselves to the development of tomorrow s technology today Lake Shore serves a worldwide network of Customers including university and national laboratories aerospace and other industries as well as many of the premier companies around the world
8. finos for particular purpose wib pect o the prodct Some countries sts or provinces do ot alow imation on an pled warranty othe above nian or exclusion migh not apply to you This warranty gives you specifi legal rights and Fou sgh ako ave ber its iar vaty Gora couty county siate a siz er Province o proide 2 To the estent alowed by applicable law the remedios in this warranty statement ar Your sole and Suha remedies Except othe extent prohibited by applicable law no event wil lke shore ar any of its subsidies lle or suppliers be lable for dace special nena consequentia or other doma cilia ost rol st u oe dove costs aring out of he use nab To use or ul of we of b produt thee based in warranty contract tort or otber legal theory and whether or not like shore hs been hed ofthe possibly of such damages Your we of the Produet i emisdly your own rid Some runs st and provinces do not allow the exchson of ability fr meena or coesequewia image so toe above ritos may ot glo you 9 Except 1o e extent allowed by applicable Iaw the erms of his nied warranty stement do not hcl restrict or modiy and are oam to I mandatory amo riglas applieabie i Be sale o e Lake Shore ceris that this product hat been inspected and tested i accordance with it published specicaons and it this produet met ts publabed specifications a he time of shpat The accuracy 4 calibration of his produet at he ume ot shipment are aceae lo the Use States Nati
9. i a defective wibout clare ta e owner for Parts sonic labore soca customary rum spring co Any sud replacement for he Product may Be eser nw or equivalent performance 1o new Replacement ar repaired parts wil e warranted far only e unexpired portion ot e origina waranty oc 90 days whichever i gre 2 Lake Shore warrants the Product only if it has boen sold by an authorized Lake Shore employee sales Seprsentatae dealer or original equipment manufacturer OEM 3 The Product may comain emanuficured parts equivalent to new in performance or may have been 44 The Warranty Period begins on the date of delivery of the Product or later on the date of installation of the Pract if he Product installed by Lake Shore provided that if you schedule or delay ib Lake Shore installation for more an 30 daya after delivery the Warranty Period Pop on the 31st day aller delivery 5 Tuis ined warst does mot apply to defects in the Product resulting om a improper or inadequate inkasncs repair or calibration b fases Sofware and nonectargale banieres c solam insti Pants or other supplies no amid by Lak Shore Q waar modifiention or mise e pero biside of be pubescens o improper jt preparation br maintenance Te the estent allowed by applicable hw the above warranties are exclusive amd po other warranty or onion whether writen s eral i expressed or implied Lake dore Specialy disclaims any imd womans or conditons of merchant stisacery quality andor
10. not apply Stycast epoxy over the DT 470 SD package sensor stress may shift the readings In all cases periodically inspect the sensor mounting to verify good thermal contact to the mounting surface is maintained 2 53 Measurement Errors Due To AC Noise Poorly shielded leads or improperly grounded measurement systems can introduce AC noise into the sensor leads In diode sensors the AC noise shifts the DC voltage measurement due to the diode non linear currenvoltage characteristics When this occurs measured DC voltage is too low and the corresponding temperature reading is high The measurement error can approach several tenths of a kelvin To determine if this problem exists perform either procedure below 1 Place a capacitor across the diode to shunt induced AC currents Capacitor size depends on the noise frequency If noise is related to power line frequency use a 10 uF capacitor If AC coupled digital noise is suspected digital circuits or interfaces use a 0 1 to 1 pF capacitor In either case if measured DC voltage increases there is induced noise in the measurement system 2 Measure AC voltage across the diode with an AC voltmeter or oscilloscope Most voltmeters do not have the frequency response to measure noise associated with digital circuits or interfaces which operate in the MHz range For a thorough discussion of this potential problem and the magnitude of error which may result request the paper Measur
11. GEN Helium and Nitrogen are colorless odorless and tasteless gases They liquefy when properly cooled Liquid Helium LHe and liquid nitrogen LNs may be used in conjunction with the Model 120CS Although not explosive there are certain safety considerations in the handling of LHe and LN 1 24 Handling Cryogenic Storage Dewars Operate all cryogenic containers dewars in accordance with manufacturer instructions Safety instructions are normally posted on the side of each dewar Keep cryogenic dewars in a well ventilated place protected from the weather and away from heat sources 1 2 2 LHe and LN Safety Precautions Transfer LHe and LNz and operate storage dewar controls in accordance with manufacturer supplier instructions During transfer follow all safety precautions written on the storage dewar and recommended by the manufacturer WARNING Liquid helium is a potential asphyxiant and can cause rapid suffocation without warning Store and use in an adequately ventilated area DO NOT vent the container in confined spaces DO NOT enter confined spaces where gas may be present unless well ventilated If inhaled remove to fresh air If not ion If breathing is difficult give WARNING Liquid helium can cause severe frostbite to exposed body parts DO NOT touch frosted pipes or valves For frostbite consult a physician immediately If a physician is unavailable warm the affected parts with water that is near body t
12. ation before attempting any repair 1 Instrument model and serial number 2 Username company address and phone number 3 Malfunction symptoms 4 Description of system 5 Returned Goods Authorization RGA number Repack the system in its original container if available Affix shipping labels and FRAGILE warnings Write RGA number on the outside of the container or on the packing slip If not available consult Lake Shore for shipping and packing instructions Installation 24 Lake Shore Model 120CS User s Manual 23 POWER AND GROUND REQUIREMENTS The Model 120CS requires a power source of 90 to 125 or 210 to 250 VAC 50 or 60 Hz single phase 3 VA maximum It ships with a line cord P N 115 006 for 120 VAC operation Connect to rear panel power plug Turn the unit on by pressing the red POWER button on the front panel WARNING To prevent electrical fire or shock hazards do not expose this instrument to rain or excess moisture CAUTION Verify correct voltage configuration by checking the Line Voltage Selection Block on the Model 120CS rear panel do not use the current source at other than its marked voltage To change voltage configuration refer to Chapter 4 To protect operating personnel properly ground instrument panels and cabinets per in accordance with and local codes The 3 conductor power cable when plugged into an appropriate receptacle grounds the instrument Shield sensor cables whenever po
13. behind the transformer as shown in Figure 4 1 4 Replace with a 0 2 A fuse for 110 V 115 VAC operation or a 0 1 A fuse for 220 V 230 VAC operation Use slow blow fuses CAUTION Replace fuse with the same type and rating as specified by the line voltage selected 5 Replace enclosure cover rear panel and all screws 42 LINE VOLTAGE CONFIGURATION The rear panel 3 pronged line power connector permits Model 120CS operation at either 110 or 220 VAC The configuration is indicated on rear panel in the Line Voltage Selection Block Use the procedure below to change line voltage WARNING To prevent shock hazard turn off instrument and disconnect it from AC line power and all test equipment before changing line voltage configuration Turn power switch OFF and disconnect the power cord from the unit Disconnect all test equipment from unit Service 44 Lake Shore Model 120CS User s Manual Line Voltage Configuration Continued arre oe o o e S sasa e s D Beg 0 om I N lt iu ew Vi Tnweor BEE YUY eos EU Jure 4 1 Fuse Replacement and Jumper Configurations 2 Remove two screws securing rear panel to bottom of enclosure Gently pull away rear panel and remove enclosure cover by sliding it to the back 3 Modify jumper configuration to desired line voltage as shown in Figure 4 1 4 Replace fuse to match new voltage requirements Replace enclosur
14. ctory calibrates 10 pA range to better than 0 05 Stability Better than 0 01 per day on fixed ranges Temperature Coefficient lt 0 01 per C at 10 35 C Programming Accuracy stability and temperature coefficient performance in the PRGM position depends on the programming resistor Adjust programmed output current value to about 5 with rear panel trim Compliance Voltage 11 volts 10 volts on 100 mA scale PRGM position 11 volts up to 50 mA 10 volts above 50 mA CMPL light flashes when the output voltage reaches 11 volts AC Current Ripple lt 0 01 of scale plus 40 4V RMS in a properly shielded system Line Regulation Less than 0 01 change in output for 10 change in line voltage within specified range Load Regulation Less than 0 01 change in output from 1 to 100 of compliance voltage Connections Output ground and programming terminals on rear panel terminal block Ambient Temperature Range 15 35 C 59 95 F Power 90 125 or 210 250 VAC 50 60 Hz 3 VA Maximum Size 106 x 41 x 164 mm 4 2 x 1 6 x 6 5 inches Weight 0 5 kilograms 1 1 pounds NOTES 4 Product Specifications are subject to change without notice 2 The electrical specifications given are for a unit operating at the factory at current output of 10 pA a different output current may affect some specifications 12 Introduction Lake Shore Model 120CS User s Manual 12 HANDLING LIQUID HELIUM AND LIQUID NITRO
15. d the sample to which the sensor mounts This refiects as a real temperature offset between what is measured and the true sample temperature Eliminate such temperature errors with proper selection and installation of connecting leads To minimize heat flow through the leads select leads of small diameter and low thermal conductivity Phosphor bronze or Manganin wire is commonly used in sizes 32 or 36 AWG These wires have a fairly low thermal conductivity yet electrical resistance is not large enough to create measurement problems Thermally anchor lead wires at several temperatures between room temperature and cryogenic temperatures to guarantee no heat conduction through the leads to the sensor 2 5 2 Sensor Mounting Before installing a diode sensor identify or sro s0 which lead is the anode and which is Diode Sensor Leads the cathode When viewed with the base down and the leads towards the observer the anode is on the right and the cathode is on the left The Lake Shore DT 470 SD silicon diode sensor lead configuration is shown to the right n m rode For other sensors read accompanying literature or consult the manufacturer to positively identify sensor leads Lead identification should remain clear even after sensor installation Record the sensor serial number and location On the DT 470 SD the base is the largest flat surface It is sapphire with gold metalization over a nickel buffer
16. e cover rear panel and all screws 43 10 pA CURRENT CALIBRATION This unit was thoroughly tested and calibrated to published specifications prior to shipment However periodic recalibration is recommended every 6 months to ensure accuracy Diode temperature sensors require a 10 pA excitation current accurate to 0 05 to meet specifications The Model 120CS is calibrated to better than 0 05 on the 10 pA range and meets 0 1 accuracy on the other fixed current ranges selected by the Current Selector Switch Requirements a digital volt meter DVM with 41 digit resolution or better and a 100 KO precision resistor with a tolerance of 20 01 NOTE Calibration accuracy is limited to the resistor accuracy plus DVM accuracy at 1 0000 volts 42 Service Lake Shore Model 120CS User s Manual 10 pA Current Calibration Continued 1 Set the Current Selector Switch to 10 WA and OUTPUT Toggle Switch to NORM 2 Connect 100 KQ precision resistor as the load between the OUT and OUT terminals 3 Connect DVM HI terminal to OUT terminal and DVM LO terminal to OUT terminal across the 100 KQ precision resistor load 4 Select DC Volts on the DVM 5 Adjust rear panel ADJ trimmer until the DVM reads 1 0000 volt Resume normal operation 4 4 PRGM MODE CALIBRATION The calibration procedures below ensure that the equation 1 1500 15 R is valid for all of the R values given in Table 3 1 Refer to Paragraph 4 4 1
17. e only plastic bags approved for storage of ESD material 6 Do not handle ESDS devices unnecessarily or remove from the packages until actually used or tested 14 SAFETY SUMMARY Observe these general 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 Ground The Instrument To minimize shock hazard connect instrument chassis and cabinet to an electrical ground The instrument comes with a 3 conductor AC power cable Plug it into an approved three contact electrical outlet or use a three contact adapter with the green ground wire firmly secured to an electrical ground safety ground at the power outlet The power cable jack and mating plug meet Underwriters Laboratories UL and International Electrotechnical Commission IEC safety standards 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 Introduction 05 Lake Shore Model 120CS User s Manual Keep Away From Live Circuits Operating personnel must not remove instrument covers Refer component replacement and internal adjustm
18. ement System Induced Errors In Diode Thermometry J K Krause and B C Dodril Rev Sci Instr 57 4 661 April 1986 from Lake Shore To greatly reduce potential AC noise connect twisted leads pairs between the measurement instruments and the diode sensors Use 32 or 36 AWG Lake Shore Duo Twist Cryogenic Wire which features phosphor bronze Wire twisted at 3 15 twists per centimeter 8 twists per inch Refer to the Lake Shore Product Catalog or contact Lake Shore for further information 24 Installation Lake Shore Model 120CS User s Manual 26 RACK MOUNTING The Model 120 can install in a standard size panel EIA rack space If you ordered a 2090 rack mounting adapter follow the installation instructions below See Figure 2 1 1 Remove front feet on bottom of unit and attach lower rack piece by threading two of the four screws provided into the front feet holes 2 Locate the two mounting hole access covers on the top of the unit Attach the other rack with the remaining screws Installation 25 Lake Shore Model 120CS User s Manual 925679 0246 649 me na 8 Q ag Hole Sizes A 0 189 0 480 Diameter 4 Places B 0 169 0 429 Diameter 2 Places 35 Model 120CS Front Panel Q eos Q i n 144 144 25 58 s ss pk 4 18 106 17 Figure 2 1 Model 2090 Rack Mounting 26 Installation Lake Shore Model 120CS User s Manual
19. emperature Two essential safety aspects of handling LHe are adequate ventilation and eye and skin protection Although helium and nitrogen gases are non toxic they are dangerous because they replace air in a normal breathing atmosphere Liquid helium is an even greater threat because a small amount of liquid evaporates to create a large amount of gas Store and operate cryogenic dewars in open well ventilated areas Introduction 13 Lake Shore Model 120CS User s Manual LHe and LN Safety Precautions Continued When transferring LHe and LN protect eyes and skin from accidental Contact with liquid or the cold gas issuing from it Protect eyes with full face shield or chemical splash goggles safety glasses even with side shields are inadequate Always wear special cryogenic gloves Tempshield Cryo Gloves or equivalent when handling anything that is or may have been in contact with the liquid or cold gas or with cold pipes or equipment Wear long sleeve shirts and cuffless trousers long enough to prevent liquid from entering shoes 1 23 Recommended First Aid Post an appropriate Material Safety Data Sheet MSDS obtained from the manufactureridistributor at every site that stores and uses LHe and LN The MSDS specifies symptoms of overexposure and first aid If a person exhibits symptoms of asphyxia such as headache drowsiness dizziness excitation excessive salivation vomiting or unconsciousness remove to fres
20. ents to qualified maintenance personnel Do not replace components with power cable connected To avoid injuries always disconnect power and discharge Circuits before touching them Do Not Substitute Parts Or Modify Instrument Do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to an authorized Lake Shore Cryotronics Inc representative for service and repair to ensure that safety features are maintained 15 SAFETY SYMBOLS Direct current power line Alternating current power line Alternating or direct current power line Three phase altemating current power line Earth ground terminal Protective conductor terminal Frame or chassis terminal On supply Off supply Equipment protected throughout by double insulation or reinforced insulation equivalent to Class II of IEC 536 see Annex H B O O Ae Caution High voltages danger of electric shock Background color Yellow Symbol and outline Black Caution or Warning See instrument documentation Background color Yellow Symbol and outline Black Fuse t P P 16 Introduction Lake Shore Model 120CS User s Manual CHAPTER 2 INSTALLATION 20 GENERAL This chapter covers inspection and unpacking in Paragraph 2 1 repackaging for shipment in Paragraph 2 2 sensor installation recommendations in Paragraph 2 3 power and ground requirements in Paragraph 2 4 load
21. es In Table 3 1 the calculated R and the closest standard 1 resistance values are given for various currents 2 Place the OUTPUT Current Selector Switch in PRGM 3 Move the OUTPUT Toggle Switch to NORM or REVRS 4 Turn the Model 120CS on by pressing the red POWER button on the front panel 5 Adjust the PRGM ADJ trimmer located on the rear panel in order to compensate for variations in the programming resistor tolerance CAUTION Do not adjust the trimmer labeled ADJ It calibrates the 11 fixed output currents Table 3 1 Output Currents and Corresponding 1 Programming Resistances Approximate Calculated R _ Closest Standard 1 Current Ohms Resistance Value Ohms AA 1 499 985 15M uA 499 985 499K 10 pA 149985 150K 30 yA 49 985 499K 100 pA 14985 15K 300 pA 4 985 499 K 1mA 1485 15K 3mA 485 487 10mA 185 137 30mA ES 348 100 mA 0 0 um panel PRGM ADJ timer o adjust output curant 25 The PRGM programming terminals have an interna 15 Q resistor in series that limits current to 100 mA in the event of a short circuit across the PRGM terminals In this mode the total output current flows through the programming resistor Use a resistor with a power rating at least 10 times the power actually dissipated A Y watt resistor suffices for any output current below 10 mA A 1 wat resistor is required for al currents above 10 mA Operation 3 3 Lake Shore Model 120CS User
22. for DC Ampere range Calibration and Paragraph 4 4 2 for DC Voltage range Calibration 444 Current Calibration Using DC Ampere Range of DVM Requirements a digital volt meter DVM with 4Y digit resolution or better and a shorting wire NOTE Calibration accuracy is limited to the DVM current measurement accuracy 1 Set Current Selector Switch to PRGM and the OUTPUT Toggle Switch to NORM 2 Place a shorting wire between the rear panel PRGM terminals 3 Connect DVM HI terminal to OUT terminal and DVM LO terminal to OUT terminal 4 Select DC Amperes on the DVM 5 Adjust rear panel PRGM ADJ trimmer until DVM reads 100 00 mA 6 Resume normal operation Service 43 Lake Shore Model 120CS User s Manual 44 2 Current Calibration Using DC Voltage Range of DVM Requirements a digital volt meter DVM with 45 digit resolution or better a 10 Q precision resistor with a tolerance of 40 0176 and a shorting wire NOTE Calibration accuracy is limited to the resistor accuracy plus DVM accuracy at 1 0000 volts 1 Set the Current Selector Switch to PRGM and the OUTPUT Toggle Switch to NORM 2 Place a shorting wire between the rear panel PRGM terminals 3 Connect a 10 Q precision resistor as the load between the OUT and OUT terminals 4 Connect DVM HI terminal to OUT terminal and DVM LO terminal to OUT terminal across the 10 Q precision resistor load 5 Select DC Volts on the DVM 6 Adjust rear panel
23. h air if breathing is difficult give oxygen If breathing stops give artificial respiration Call a physician immediately If exposure to cryogenic liquids or cold gases occurs restore tissue to normal body temperature 98 6 F by bathing it in warm water not exceeding 105 F 40 C DO NOT rub the frozen part either before or after rewarming Protect the injured tissue from further damage and infection and call a physician immediately Flush exposed eyes thoroughly with warm water for at least 15 minutes In case of massive exposure remove clothing while showering with warm water The patient should not drink alcohol or smoke Keep warm and rest Call a physician immediately 13 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 36 000 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
24. layer The base is electrically isolated from the sensing element and leads make all thermal contact to the sensor through the base A thin braze joint around the sides of the SD package electrically connect to the sensing element Avoid contact to the sides with any electrically conductive materia When installing the sensor make sure there are no electrical shorts or current leakage paths between the leads or between the leads and ground If IMI 7031 varnish or epoxy is used it may soften varnish type lead insulations so that high resistance shunts appear between wires if sufficient time for curing is not allowed Slide Teflon spaghetti tubing over bare leads when the possibility of shorting exists Avoid putting stress on the device leads and allow for thermal contractions that occur during cooling which could fracture a solder joint or lead if installed under tension at room temperature Installation 23 Lake Shore Model 120CS User s Manual Sensor Mounting Continued For temporary mounting in cold temperature applications apply a thin layer of Apiezon N Grease between the sensor and sample to enhance thermal contact under slight pressure The preferred method for mounting the DT 470 SD sensor is the Lake Shore CO Adapter CAUTION Lake Shore will not warranty replace any device damaged by user designed clamps or solder mounting For semi permanent mountings use Stycast epoxy instead of Apiezon N Grease NOTE Do
25. nel Operation 34 Lake Shore Model 120CS User s Manual PRGM GND OUT aago E uw WAM o o S eaa Fas Figure 3 2 Model 120CS Rear Panel 3 2 REAR PANEL FEATURES AND FUNCTIONS Terminal Block 5 position terminal block for easy connection of PRGM Programming Resistor GND Shielding Ground and OUT Output Current PRGM ADJ Program Adjust Trim Potentiometer Adjusts output current value 5 when the Current Selector Switch is set to PRGM 1ADJ Current Adjust Trim Potentiometer Adjust the 11 fixed output current values 1 during calibration The Line Voltage Selection Block indicates the fuse rating and selected line voltage 3 3 SELECTING OUTPUT CURRENT VALUE FIXED RANGES The OUTPUT Current Selector Switch selects one of 11 fixed internal current values 1 pA through 100 mA in 1X and 3X increments Dial front panel Current Selector Switch to desired fixed range 2 Move OUTPUT Toggle Switch to NORM or REVRS NOTE Ensure proper load connection and shielding Refer to Chapter 2 3 Turn On Model 120CS by pressing red front pane POWER button 32 Operation Lake Shore Model 120CS User s Manual 3 4 PROGRAM MODE 1 Connect the desired resistor to the PRGM output terminals located on the rear panel NOTE The output current I in relation to the programming resistor R in ohms is 1500 15 R milliamper
26. onal Institute of Sunda and Technology NIST forme known s the National Barend of Standards NBS oro TRADEMARK ACKNOWLEDGEMENT Manutactrens and sellers cim many designatsons as trademarks to distinguish thcir products Where hose designations appear in ths manual and Lake Shore was awane of s talem chim he designation appear Sina capi een wah a or symbol Apizon stead of Bid Instruments CalCusse Carbom Glass Cemas u Duo Twit High Temperature Camox Quad Len Quad Tvis Rav SOCP and Thanx e ademas of Lake Shore Croton c Teflon adea of DuPont De Nemours Copyright 1993 1997 1999 and 2004 by Lake Shore Cryotronics Inc All rights reserved No portion of this manual may be reproduced stored in a retrieval system or transmitted in amy form or by any means electronic mechanical photocopying recording or otherwise without the express writen permission of Lake Shore A Lake Shore Model 120CS User s Manual TABLE OF CONTENTS ChapterlParagraph Title 1 INTRODUCTION 10 General 11 System Description 12 Handling Liquid Helium and Liquid Nitragen 124 Handling Cryogenic Storage Dewars 122 LHe and LN Safety Precautions 123 Recommended First Aid 13 Electrostatic Discharge 134 Identifying ESDS Components 132 Handling ESDS Components 14 Safety Summary 15 Safety Symbols 2 INSTALLATION 20 General 24 24 Inspection and Unpacking 24 22 Repackaging For Shipment 24 23 Power and Ground Requirements 22
27. s Manual Program Modo Continued The programming resistor temperature coefficient affects output current thermal stability To maintain the 0 01 C temperature coefficient specification use a programming resistor with a temperature coefficient of 10 PPMP C or better Programming resistor accuracy determines output current accuracy For example if a 1 5 MO 1 resistor is used to program a 1 H output current output current accuracy cannot be more than 1 In this case the built in 15 Q only contributes 0 001 difference The PRGM ADJ trimmer can compensate for variations in programming resistor tolerance and the internal 15 0 resistor 34 Operation Lake Shore Model 120CS User s Manual CHAPTER 4 SERVICE 40 GENERAL This chapter covers Model 120CS maintenance Fuse replacement is discussed in Paragraph 4 1 line voltage configuration in Paragraph 4 2 10 pA current calibration in Paragraph 4 3 and PRGM mode calibration in Paragraph 4 4 44 FUSE REPLACEMENT WARNING To prevent shock hazard turn off instrument and disconnect it from AC line power and all test equipment before replacing fuse 1 Turn POWER switch Off and disconnect power cord from unit Disconnect all test equipment from unit 2 Remove two screws securing rear panel to bottom of enclosure Gently pull away rear panel and remove enclosure cover by sliding it to the back 3 Remove fuse with a fuse puller The fuse is located
28. ssible Attach the shields to the connector shield pin 24 LOAD CONNECTION Connect the load temperature sensor to the and OUT terminals on the Terminal Block on the rear panel Use proper shielding techniques to minimize line frequency AC noise on the leads This is more critical at low currents with high resistance 2 5 SENSOR INSTALLATION RECOMMENDATIONS Although the Model 120CS acts as a current source for any application it can provide the 10 pA excitation current for Lake Shore 400 Series 500 Series and TG 120 Diode Sensors Refer to the Lake Shore Product Catalog for installation details and sensor specifications Call Lake Shore for copies of application notes or sensor installation questions Although a sensor is not provided with the Model 120CS below are general recommendations on sensor installation 1 Do not ground the sensor 2 Shield leads and connect shield wire to SHIELD on screw terminal connector only Do not connect shield at other end of cable 3 Keep leads as short as possible 4 Use twisted pair wire Use Lake Shore Duo Twist wire or equivalent for two wire or Quad Twist wire or equivalent for four wire applications 5 Thermally anchor lead wires 22 Installation Lake Shore Model 120CS User s Manual 2 5 1 Connecting Sensor Leads Excessive heat flow through connecting leads to any temperature sensor may differ the temperature between the active sensing element an
Download Pdf Manuals
Related Search