1433 SerieS High-Accuracy Decade resistor User and Service Manual
Contents
1. N WARNING N OBSERVE ALL SAFETY RULES WHEN WORKING WITH HIGH VOLTAGES OR LINE VOLTAGES Dangerous voltages may be present inside this instrument Do not open the case Refer servicing to qulified personnel HIGH VOLTAGES MAY BE PRESENT AT THE TERMINALS OF THIS INSTRUMENT WHENEVER HAZARDOUS VOLTAGES 45 V ARE USED TAKE ALL MEASURES TO AVOID ACCIDENTAL CONTACT WITH ANY LIVE COMPONENTS USE MAXIMUM INSULATION AND MINIMIZE THE USE OF BARE CONDUCTORS WHEN USING THIS INSTRUMENT Use extreme caution when working with bare conductors or bus bars WHEN WORKING WITH HIGH VOLTAGES POST WARNING SIGNS AND KEEP UNREQUIRED PERSONNEL SAFELY AWAY A CAUTION A DO NOT APPLY ANY VOLTAGES OR CURRENTS TO THE TERMINALS OF THIS INSTRUMENT IN EXCESS OF THE MAXIMUM LIMITS INDICATED ON THE FRONT PANEL OR THE OPERATING GUIDE LABEL Contents Chapter 1 INTRODUCTION lt lt lt lt lt lt coiiiriari nan Rudd xu any x dax an cix ig 1 1 Product Overview 1 2 Accessories Included 1 3 Accessories Options Avail A LEBE Chapter 2 SPECIFICATIONS cocinar cs Chapter 3 OPERATION 3 1 Initial Inspection and Setup ite 3 2 Connection nene 3 2 1 General Considerations eee nnne enne 3 2 2 Electrical Considerations eene eene 3 2 3 Four Wire Kelvin ead Connections aeterne ies 3 2 4 The2. PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT 4 1433 SERIES High Accuracy Decade Resistor User and Service Manual GenRad 1433 19 1 k DECADE RESISTOR Y n STEPS 800 mA MAX Copyright 2009 IET Labs Inc Visit www ietlabs com for manual revision updates 1433 im May 2009 NNNNA E ET LA B S N www ietlabs com 534 Main Street Westbury NY 11590 TEL 516 334 5959 800 899 8438 FAX 516 334 5988 PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT 4 E ET LA B NC www ietlabs com 534 Main Street Westbury NY 11590 TEL 516 334 5959 800 899 8438 FAX 516 334 5988 WARRANTY We warrant that this product is free from defects in material and workmanship and when properly used will perform in accordance with applicable IET specifications If within one year after original shipment it is found not to meet this standard it will be repaired or at the option of IET replaced at no charge when returned to IET Changes in this product not approved by IET or application of voltages or currents greater than those allowed by the specifications shall void this warranty IET shall not be liable for any indirect special or consequential damages even if notice has been given to the possibility of such damages THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES EXPRESSED OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTIBILITY OR FITNESS FOR ANY PARTICULAR PURPOSE
3. capabilities and limitations of the test instruments used A resistance bridge may be employed and there are direct reading resistance meters or digital multimeters available that can verify the accuracy of these units especially when used in conjunction with standards that can serve to confirm or improve the accuracy of the test ing instrument Such test instruments must be significantly more accu rate than 100ppm 2 mQ for all applicable ranges allowing for a band of uncertainty of the instrument itself A number of commercial bridges and meters exist that can perform this task consult IET Labs It is important to allow both the testing instrument and the 1433 to stabilize for a number of hours at the nominal operating temperature of 23 C and at nominal laboratory conditions of humidity There should be no temperature gradients across the unit under test Substantial Kelvin type 4 wire test terminals should MAINTENANCE 1433 Series be used to obtain accurate low resistance read ings It is convenient once the zero resistance has been determined to subtract it from the remaining measurements This can be automatically done in many instruments which have an offset subtraction capability 4 4 Calibration Procedure 1 Determine the proper metrological practices Allow a confidence band for the uncertainty of the measuring instrument and setup 2 Confirm the zero resistance of the unit 3 Determine the allowabl
4. low resis tance or low resistance increments are important take care when connecting to the terminals of the decade box In particular in order to keep contact resistance to a minimum take the most substantial and secure connection to the binding posts They accept banana plugs telephone tips spade lugs alligator clips and bare wire The largest or heaviest mating connection should be made and where applicable the binding posts should be securely tightened These considerations may be relaxed whenever single milliohms are considered insignificant for the task being performed 3 2 3 Four Wire Kelvin Lead Connections Whenever possible 4 wire Kelvin leads the ideal connection should be employed Such a connection minimizes the effects of contact resistance and ap proaches ideal performance If the four terminals are available as clamps similar to alligator clips they may be connected to the necks of the binding posts If the four terminals are available separately the optimal connection is shown in Figure 3 1 where the current leads are introduced into the top of the binding posts and the voltage leads at the necks 1433 Series Figure 3 1 Optimal 4 Wire Kelvin Lead Connection 3 2 4 Thermal emf Considerations The highest quality low emf components are used in the 1433 Series There nevertheless may be some minute thermal emf generated at the test leads where they contact the gold plated binding posts This
5. Calibration Certificate 4 SPECIFICATIONS 1433 Series Chapter 3 OPERATION 3 1 Initial Inspection and Setup This instrument was carefully inspected before ship ment It should be in proper electrical and mechanical order upon receipt An OPERATING GUIDE is attached to the case of the instrument to provide ready reference to speci fications 3 2 Connection 3 2 1 General Considerations The 1433 Series Decade unit provides three terminals labeled H high L low and G ground The H and L terminals are connected to the set resistance the G terminal is connected to the case The G terminal may be used as a guard or shield terminal It may also be connected using a shorting link to the L terminal to allow two terminal as opposed to three terminal measurements In order to make the most stable measurements de termine which is the more sensitive of the two user leads 1 6 the one going into a higher impedance This lead should be connected to the more protected one of the two 1433 terminals That would either be the 1433 terminal that is shorted to the case or the LOW 1433 terminal whenever neither is connected to the case If switches have not been operated for an extended period they should be rotated a few times to assure that contact resistance is within specifications OPERATION 3 2 2 Electrical Considerations In order to make proper use of the full performance capabilities of the 1433 unit especially if
6. L N AL N AL where Lo 0 1 uH per decade x number of decades in unit 0 2 uH AE AL ou L step values from specifications N settings of corresponding decades C Cot MC where C 15 pF C 20 pF M number of unused decades set to zero preceding first decade used The phase angle Q for this circuit is Qzo L R RC At low values of R the L R term is dominant at high values of R the RC term is more important The effective series resistance is OPERATION u R Rs TRO The effective parallel resistance is 27 2 Rp R 1 T At low values the series resistance remains constant to rather high frequencies because inductance has no effect on Rs At very low values skin effect increases Rs At high values the series resistance falls off rather rapidly with frequency because of capacitance The parallel resistance however is not affected by the lumped capacitance shown in the simple equivalent circuit see Figure 3 2 The parallel value is affected by distributed capacitance and dielectric loss not shown An approximate equation that considers these effects on Rp is o E R The oR 10 term represents dielectric loss the next term represents distributed capacitance in the first decade used not zero and the last term represents distributed capacitance in the first decade if it is not used set to zero where Ry is the total possible value of that decade The last term is not used if the firs
7. bute to thermal emf problems With a resolution as low as 1 mQ and a maximum available resistance of over 111 MQ the 1433 series may be used for exacting precision measurement applications requiring high accuracy good stability and low zero resistance They can be used as compo nents of dc and ac bridges for calibration as transfer standards and as RTD simulators The 1433 Series may be rack mounted to serve as components in measurement and control systems This series is part of a family of resistance substitu ters suited to fill many engineering and testing needs Consult IET for High power substituters up to gt 400 W High resistance substituters to 1 TO RTD simulators Laboratory standard grade substituters to 1 ppm accuracy Programmable substituters EEE 488 or BCD GenRad 1433 19 kQ DECADE RESISTOR LO 0 id 3 e E Figure 1 1 1433 Series High Accuracy Decade Resistor 1433 Series This page is intentionally left blank 2 INTRODUCTION 1433 Series Chapter 2 SPECIFICATIONS For the convenience of the user the pertinent specifications are given in an OPERATING GUIDE affixed to the case of the instrument Range Overall Accuracy 1 mQ to 111 111 111 110 Q in 1 mA steps The difference between the resistance at any setting and at the Zero setting is equal to the indicated value 0 01 2 mQ Decade Specifications Resistance Total Decade Stability Power step ee per Step Resis
8. e upper and lower limits for each resistance setting of each decade based on the specified accuracy For the 1433 series these limits for any resis tance R are R 0 0001 R 2 mQ 4 Confirm that the resistances fall within these limits after subtraction of the zero resistance 5 Ifany resistances fall outside these limits the as sociated switch assembly may require trimming or replacement 4 5 Schematic Refer to Figure 4 1 for a schematic of the 1433 de cade unit MOST SIGNIFICANT MOST SIGNIFICANT RESISTOR DECADE STEP 10 LEAST SIGNIFICANT LEAST SIGNIFICANT bc DECADE Figure 4 1 1433 Series Schematic Diagram MAINTENANCE 1433 Series 4 3 Replaceable Parts List Model Ref IET Pt No 01 1033 8 0312 01 1033 8 0310 01 1008 1 0310 1433 4300 KNB 1433 3100 1433 4000 X 001 1433 4000 X 0 01 1433 4000 X 0 1 1433 4000 X 1 1433 4000 X 10 1433 4000 X 100 1433 4000 X 1k 1433 4000 X 10k 1433 4000 X 100k 1433 4000 X 1M 1433 4000 X 10M Description Binding Post Red Binding Post Black Binding Post Gold Knob Assembly Foot N Zziziziziziziziziziziziz Blu ot Shown ot Shown 1 mQ step Decade Switch Assembly 10 mQ step Decade Switch Assembly 100 mQ step Decade Switch Assembly 1 Q step Decade Switch Assembly 10 Q step Decade Switch Assembly 100 O step Decade Switch Assembly 1 kQ step Decade Switch Assembly 10 kQ step Decade Switch Assembly 100 kQ step Decade Switch Ass
9. ecade 1433 09A 111 100 000 4 may be assumed counting decades down 1433 10 1 111 1 5 from the highest Thus if the third decade 1433 12 11 111 5 from the top is the highest resistance a value 1433 14 111 110 5 of 45 to 60 pF may be assumed If the high 1433 16 1 111 100 5 est decade in the unit is in use the effective 1433 18 11 111 000 5 capacitance is 15 to 20 pF regardless of the 1433 18A 111 110 000 5 settings of the lower resistance decades 1433 19 1 111 11 6 Switches 1433 20 11 111 1 6 Continuous rotation solid silver alloy contacts 1433 22 111 111 6 contact resistance of less than 1 mQ capacitance 1433 24 1 111 110 6 of less than 1 pF between contacts lifetime in 1433 26 11 111 100 6 excess of 1 million cycles 1433 27 111 111 000 6 Maximum voltage to case 1433 28 11 111 11 7 2000 V peak 1433 29 111 111 1 7 Terminals 1433 31 1 111 111 0 1 7 Gold plated tellurium copper low thermal emf 1433 33 11 111 110 1 7 binding posts on standard 3 4 inch spacing shield 1433 34 111 111 100 10 7 8 8 8 8 9 9 1433 39B 111 111 111 0 1 1433 40A 11 111 111 110 0 001 1433 40 111 111 111 1 0 01 1433 41 111 111 111 11 0 001 TIT 48 3 cm W x 17 8 cm H x 17 8 cm D waren Environmental OPTIONS Operating 10 to 40 C lt 80 RH e RO Rear output binding posts Storage 20 to 65 C e Rack mountable case for standard 19 rack Supplied with unit Instruction manual
10. embly 1 MQ step Decade Switch Assembly 10 MQ step Decade Switch Assembly ot Shown ot Shown ot Shown ot Shown ot Shown ot Shown ot Shown ot Shown ot Shown ot Shown Table 4 2 Replacement List 1433 19 1 kQ DECADE RESISTOR Formerly manufactured by GenRad 5 10 STEPS 800 mA MAX 10 2 STEPS 250 mA MAX 100 Q STEPS 80 mA MAX A Figure 4 2 1433 Replaceable Parts 10 MAINTENANCE
11. emf will not manifest itself if an ac measurement instrument is employed It will also be eliminated if a meter with a True Ohm capability is used Oth erwise it may appear as a false component of the dc resistance measurement It is also possible to take a second measurement with the leads reversed and average the readings 3 3 Dial Setting Whenever the dials are used in positions 0 9 the resulting resistance is read directly Both the decimal point and the steps are clearly marked on the panel For additional flexibility and range each decade provides a 10 position setting This 10 position on any one decade equals the 1 position on the next higher decade It adds about 11 to the nominal total decade resistance To determine the resistance obtained when one or more 10 settings are used simply add 1 to the next higher decade For example a setting of 3 6 10 0 10 Q becomes 3 3 0 0 0 0 6 6 0 0 0 10 1 0 0 0 0 0 0 10 Too TOT 3 7 0 1 0 and a setting of 10 10 10 10 10 10 Q becomes 10 10 0 0 0 0 0 10 1 0 0 0 0 10 1 0 0 0 0 10 1 0 0 0 10 1 0 0 10 1 0 TOT 1 1 1 1 1 1 0 3 4 Principles of Operation The best approximation of a complete equivalent circuit for a 1433 Decade Resistor is shown in Figure 3 2 R L L H o t G Figure 3 2 A simplified equivalent circuit for a decade box with the low L terminal tied to case In Figure 3 2 R setting of the decade box L
12. f contaminants and dust to the inside of the instrument If it is maintained in a clean or air conditioned environment cleaning will seldom be required In a contaminated atmosphere cleaning may be required Should cleaning be needed do the following 1 Remove the 4 housing screws from the sides of the instrument and remove the housing 2 Remove any dust or debris using optical grade dry compressed air or a clean brush 3 Should switch contact cleaning or lubrica tion be required as may be indicated by an increase in the zero resistance this may be done be spraying the switch contacts with a conditioning compound such as WD 40 or Deoxit from Caig Laboratories 4 Replace the housing and reinstall the 4 hous ing screws The front panel should be periodically cleaned to eliminate any leakage paths around the binding posts To clean the front panel do the following Wipe the front panel clean using alcohol and a lint free cloth 4 2 Calibration Interval The recommended calibration interval for 1433 Se ries decade substituters is twelve 12 months The calibration procedure may be carried out by the user if a calibration capability is available by IET Labs or by a certified calibration laboratory If the user should choose to perform this procedure then the considerations below should be observed 4 3 General Considerations It is important whenever testing the 1433 Series De cade Units to be very aware of the
13. ics of stability temperature coeffi cient power coefficient and frequency response There are over 30 models available covering a wide resistance range from 1 mQ to over 111 MQ The 1433 Series employs stable very low resistance switches with silver alloy contacts A special design keeps zero resistance to less than 1 mQ per decade Self cleaning keeps the silver contacts from becoming tarnished when unused or when only low currents are passed through them This is most often the case when only minute test currents are drawn by digital multimeters or other test instruments Contact resis tance is stable and remains low and repeatable The dials labeled 0 to X 10 offer smooth rotation from position to position with no stops Each dial has an overlap X 10 position for maximum convenience and flexibility in setting and adjusting resistance val ues The resistance per step and maximum current of each dial are clearly shown on the front panel Electri cal shielding is provided by an attractive aluminum cabinet and front panel The resistance elements have no electrical connection to the cabinet and panel a separate shield terminal is provided High quality gold plated tellurium copper binding posts serve to minimize the thermal emf effects which can introduce errors into dc resistance measurements INTRODUCTION All other conductors within the instrument as well as the solder employed contain no metals or junctions that contri
14. rmal emf Considerations aa a ena ens 3 3 Dial Setting 3 4 Principles of Operation Chapter 4 MAINTENANCE 4 1 Verification of Performante noo cia 4 1 1 Preventive Maintenance nennen 4 1 2 Calibration Interval 4 1 3 General Considerations ierit ttr eet eroe trece lectores aSa 4 1 4 Calibration Procedure 4 2 4 3 Replaceable Parts List Tables and Figures Figure 1 1 1433 Series High Accuracy Decade Resistor 1 Figure 3 1 Optimal 4 Wire Kelvin Lead Connection 6 Figure 3 2 A simplified equivalent circuit for a decade box with the low L terminal WOO TO CAS MN RNC c PETENS 6 Figure 3 3 Equivalent three terminal circuit for a decade box with neither terminal TER NEM EN HER 7 Figure 3 4 Approximation of distributed capacitance effects 7 Figure 4 1 1433 Series Schematic Diagram id ia 9 Table 4 2 Replacement List an 10 Figura 4 2 1433 Replaceable PS isa 10 1433 Series Chapter 1 INTRODUCTION 1 1 Product Overview The 1433 Decade Resistors are a family of instruments providing a very broad choice of high performance resistance sources Any number of decades from one to eleven is available The 1433 is a precision resistance source with excel lent characterist
15. t decade is not set to zero When the case is not tied to either terminal the decade resistor becomes a three terminal circuit as shown in Figure 3 3 Rp R 1 105 49 R 1077 259 RRy1074 Cs Figure 3 3 Equivalent three terminal circuit for a decade box with neither terminal tied to case In Figure 3 3 OPERATION 1433 Series R setting of the decade box L L N AL N AL where Lo 0 1 uH per decade x number of decades in unit 0 2 uH A L A L L step values from specifica tions N settings of corresponding decades Ca 10 Ma 8 pF where Ma number of unused decades set to zero preceding first decade used Cb 20 Mb 20 pF where Mb number of unused decades set to zero preceding first decade used Cs 2 pF gees aotm f G R c R L H t 2 2 6 Figure 3 4 Approximation of distributed capacitance effects There is also some distributed capacitance Cd from the resistor to the case as shown in Figure 3 4 This capacitance has the effect of increasing the effective inductance by an amount of approximately N R C x 105 where N is the setting of the first used not zero decade R is the total value of the decade resistor and C is 2 pF 1433 Series Chapter 4 MAINTENANCE 4 1 Preventative Maintenence Keep the unit in a clean environment This will help prevent possible contamination 1433 is packaged in a closed case which limits the entry o
16. tance em lene 1 C O 39 13 9 Eur un 100 ma 368 w o os am o a e s om wok ima eo Rm os imo ow o oor 0s 0 Frome ww o on 0 1 Typical Frequency Characteristics aS ee 22 Tre SSA IN IT ENEE 100 200 10 FREQENCY IN kHz SPECIFICATIONS 3 1433 Series Typical Value of Zero Impedance Ordering Information Zero Resistance Ro terminal provided 1433 35 111 111 110 0 001 1433 36 1 111 111 10 0 01 1433 37 11 111 111 0 0 1 1433 38 111 111 110 1433 39 1 111 111 11 0 001 1433 39A 11 111 111 1 0 01 Mechanical 37 5 cm W x 8 9 cm H x 10 2 cm D 3 5 decade 2 0 kg 4 3 Ib 14 75 x 3 5 x 4 48 x4 43 9 cm W x 8 9 cm H x 102 cm D 2 2 kg 4 8 Ib 0 001 Q decade at dc Total Ohms No 0 04 O decade at 1 MHz No Q step of dials proportional to square root of frequency 1433 01 1 11 3 above 100 kHz 1433 00 111 1 4 Zero Inductance Lo 1433 02 1 111 4 0 1 wH decade 0 2 uH 1433 04 11 110 4 Effective Shunt Capacitance C 1433 06 111 100 4 Value is determined largely by the highest de 1433 08 1 111 000 4 cade in use With the low terminal connected 1433 09 11 110 000 4 to the shield a value of 15 to 20 pF d
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