1433 SERIES High-Accuracy Decade Resistor User and Service
Contents
1. 2 Specifications Environmental conditions Operating 10 C to 40 C lt 50 RH Storage 40 C to 70 C Supplied with unit Instruction manual Calibration Certificate Historic Resolution GR model numbers Des ome ms um 3 fem f Pessoal ous pen passa imme 3 pes mon Des f nme 3 re ew Dee T H pea mee Dew ume woo pee Cus man s pee HS usse mma e pee T Desa mme e pee eem Dem me e pes pee Dess fmm pre pee Deas we oe pa pee uar mee E 1 Number of Total resistance decades Specifications 1433 Series Historic Resolution GR model numbers Number of decades Dess seme e pes T usos meme e 8 T Dum preme pens mass e ene Dese onm e wa 7 aaas o ooa msa OOT aas TTT Total resistance SuOp71109de 1433 SERIES PRECISION DECADE RESISTORS Resistance Total Max Max Power Stability Long term Temp Resistor Accuracy lt 1 MQ steps 0 01 2 mQ per step deacde current voltage per step stability coeffieient type 10 MQ steps 0 03 resistance At 23 C after subtraction of zero resistance Traceable to SI 50 ppm yr 75 ppm 3 yrs 50 ppm C Resistance i lt 50 ppm yr 75 ppnv3 yrs 20 pp s Zero Resistance S ben Ran Pe ae 50 ppm yr 75 ppm 3 yrs 20 ppm C 20 ppmiyr 25 ppm 3 yrs 20 ppm C Max Voltage to Case 2000 V peak 20 ppm yr 25 ppm 3 yrs_2. this component of the reading error by taking a second measurement with the leads reversed and averaging the readings Operation 1433 Series 3 3 Dial Setting Whenever the dials are used in positions 0 9 the resulting resistance is read directly 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 3 000 0 6 6 0 0 0 10 1 0 0 0 0 0 0 10 1 0 TOT 3 7 01 0 and a setting of 10 10 10 10 10 10 Q becomes 10 10000 0 0 10 1000 0 0 10 1 0 0 0 0 10 1 0 0 0 10 1 0 0 10 1 0 TOT l 1 1 1 1 1 0 1433 Series Chapter 4 MAINTANENCE 4 1 Preventative Maintenance Keep the unit in a clean environment This will help prevent possible contamination The 1433 is packaged in a closed case which limits the entry of 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 screws from the
3. associated switch assembly may require trimming or replacement Maintanence 1433 Series 4 5 Schematic Figure 4 1 gives the schematic of the 1433 decade unit MOST SIGNIFICANT MOST SIGNIFICANT RESISTOR DECADE STEP ro LEAST SIGNIFICANT LEAST SIGNIFICANT RESISTOR DECADE STEP Figure 4 1 1433 Series Schematic Diagram
4. overlap 10 position for maximum convenience and flexibility in setting and adjusting resistance values The resistance per step and maximum cur rent of each dial are clearly shown on the front panel Electrical shielding is provided by an attractive alumi num cabinet and front panel The resistance elements have no electrical connection to the cabinet and panel a separate shield terminal is provided Introduction High quality gold plated tellurium copper binding posts serve to minimize the thermal emf effects which can introduce errors into dc resistance measurements All other conductors within the instrument as well as the solder employed contain no metals or junctions that contribute to thermal emf problems With a minimum resistance as low as 1 mQ and a maximum available resistance of over 111 MQ the 1433 series may be used for exacting precision mea surement applications requiring high accuracy good stability and low zero resistance They can be used as components 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 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 Decade Specifications Resistance Total Max voltage Max power Stability Longsterm Ternperature
5. sides of the housing 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 or Super Lube with PTFE from Synco Chemical Corp 4 Replacethe 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 do this wipe the front panel clean using alcohol and a lint free cloth 4 2 Calibration Interval The recommended calibration interval for 1433 Series decade substituters is twelve 12 months The calibration procedure may be carried out by the user if a calibration capability is available 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 Decade Units to be very aware of the capabili ties 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 improv
6. 1433 SERIES High Accuracy Decade Resistor User and Service Manual 1433 Series Contents Chapter 1 Introduction ssssssssssssssszsgeszssvsssssvsvsggsssssssscsessgczssssvszssggsssssszvsevse 1 ti Product OVeryie we io DEUS PH RP end 1 Chapter 2 Specifications resscssssssssvssssvrsrsegvsregssysssssgsssegvrssggpasssggesssses seve 2 Decade Specifi catons cientes m ates e e dr o ead tede co eed qun tede o 2 Chapter 3 Operation onera rnit su usto tx suuni n aEEXR a EE TERR EMR teer 5 3 1 initial Inspection and Setups i er eene espere dete aepo dpt ea 5 3 2 Congdon a a OHPOP HERI 5 3 2 1 General Considerations iier eee eminet eas 5 3 22 El ctecal Considerations eicere err brit rr te e oE 5 3 2 3 Four Wire Kelvin Lead Connections essen 6 3 24 Thermal emf Considerations ensesine 6 33 JDialSebung x25 ote aen edet E Oe ne tede s 6 Chapter 4 Maintarnence enu ue rein nan tra tnn nunt ix sane aasa Yun nanora iueiai 7 Al Preventative Maintenance soe eret nn at EE HERE OE EH Eee ete y 7 42 Calibration Interval ss ceto oper tema m Ee EFE pR et 7 4 3 General Considerations iecit eere need deae cp etc e Eee boo E RE RE SER ne edd 7 AA Calibration Procedure iocis eee rut Grp e ee e ecrire naire acus 8 AS Schematic eosidete E e EDU EO D UE artt 8 4 6 Replaceable Parts List noinen etii tr REO RH UR URGERE 9 1433 Series Tables and Figures Figure 1 1 1433 Series High Accur
7. 15 ppm Switch Type Multiple solid silver alloy contacts continuous 20 ppm yr 25 ppm 3 yrs 5 ppm C widens rotation 11 positions marked 0 to 10 20 ppm yr 25 ppm 3 yrs 5ppm C aon inductie Operation If switches have not been operated for an extended 20 ppm yr 25 ppm 8yrs 5 ppm C period they should be rotated a few times in both directions to 20 ppm yr 25 ppm 8 yrs 5 ppm C restore contact resistance to specifications 20 ppm yr 25 ppm 8 yrs 5 ppm C Operating Conditions 10 to 40 C 5096 RH 50 ppm yr 100 ppm 3 yrs 10 ppm C Subject to maximum of 2000 V to case WARNING Observe all safety rules when working with high voltages or line voltages Connect the G terminal to earth ground in order to maintain the case ata safe voltage Whenever hazardous voltages gt 45 V are used take all measures to avoid accidental contact with any live components a Use maximum insulation and minimize the use of bare conductors b Remove power when adjusting switches c Post warning signs and keep personnel safely away G e n Ra d 1433 Ibl 1433 genl p4 48 02 07 2013 Figure 2 1 Sample operating guide affixed to unit SOHIS CET L 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 GU
8. IDE is attached to the case of the instrument to provide ready reference to specifications 3 2 Connection 3 2 4 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 i e the one going into a higher impedance This lead should be connected to the more protected of the two terminals H high or L low That would either be the terminal that is shorted to the case or the L terminal if neither is connected to the G 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 low resis tance or low resistance increments are important take care when connecting to the terminals In particular in order to keep contact resistance to a minimum make the most substantial and secure connection to the binding posts They accept banana plugs t
9. Uu decade per step per step tppm yr stability coefficient Resistor type p P resistance P R P a tppm 3 yrs ippm C 1ma wo eoa sv ow ma a e ov ww e Fon oa wes esv cow o Ewa ne wm ow cow 5 Fiona oa m ov osw m Poona ive zom zov sw o Fama om eres ev ow o oma swa orm oov ow o wo 10 oem Subject to maximum of 2000 V to case Accuracy Switch capacitance lt 1 MQ decades 0 01 2 mQ lt pF between contacts 10 MQ decades 0 03 Zero Inductance Lo after subtraction of zero resistance at 23 C 0 1 pH decade 0 2 uH traceable to SI x Switches Zero resistance Continuous rotation lt 1 MQ decades 1 mQ per decade at dc 10 MQ decade 3 mQ at dc Max voltage to case 11 positions marked 0 10 Multiple solid silver alloy contacts Mechanical eight Terminals Gold plated 5 way tellurium copper binding posts 3 decade ga Paa RAE with low thermal emf and low resistance Rear _ 37 6 cm W x 8 9 cm H x 10 2 cm D outputs are available as an option 4 5 decade 14 8 x 3 5 x 4 Typical Value of Zero Impedance 6 7 decades 432 0m Wx amp 9emHx 10 2 cm D Zero Resistance Ro ME o 0 001 Q decade at dc 8 9 decades 48 3 cm W x 17 8 cm H x 17 8 cm D 0 04 Q decade at 1 MHz 10 11 decades 19 x7 x7 Proportional to square root of frequency above 100 kHz
10. acy Decade Heaisior sse 1 Figure 2 1 Sample operating guide affixed to Un sees eee 4 Figure 3 1 Optimal 4 Wire Kelvin Lead Connection eee eee 6 Figure 4 1 1433 Series Schematic Diagram sees eee eee eee eee eee 8 Table 4 1 Replacement List esses sessi nennen nitens 9 Figure 4 2 1433 Replaceable Parts sssiisssse esiste 9 1433 Series Chapter 1 INTRODUCTION 1 1 Product Overview The 1433 Decade Resistors are a family of instru ments providing a very broad choice of high perfor mance resistance sources Any number of decades from one to eleven is available The 1433 is a precision resistance source with ex cellent characteristics of stability temperature coef ficient 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 marked 0 to 10 offer smooth rotation from position to position with no stops Each dial has an
11. e the accuracy of the testing instrument Such test instruments must be significantly more accu rate than 100 ppm 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 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 nomi nal laboratory conditions of humidity There should be no temperature gradients across the unit under test Maintanence Substantial Kelvin type 4 wire test terminals should be used to obtain accurate low resistance readings It is convenient once the zero resistance has been determined to subtract it from the remaining mea surements This can be automatically done in many in struments which have an offset subtraction capability 4 4 Calibration Procedure 1 Employ proper metrological practices Allow a confidence band for the uncer tainty of the measuring instrument and Setup 2 Confirm the zero resistance of the unit 3 Determine the allowable upper and lower limits for each resistance setting of each de cade based on the specified accuracy For the 1433 series these limits for any resistance R are RX 0 0001 R 2 mQ 4 Confirm that the resistances fall within these limits after subtraction of the zero resistance 5 If any resistances fall outside these limits the
12. ele phone 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 1433 Series 3 2 3 Four Wire Kelvin Lead Connections Whenever possible 4 wire Kelvin leads the best 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 on a 3 terminal unit If the four wire connections are available separately the optimal connections are shown in Figure 3 1 and Figure3 2 HIGH CURRENT Figure 3 1 4 Wire connection to a 3 terminal unit Figure 3 2 4 Wire connection to a 5 terminal unit 6 Operation 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 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 Otherwise it may appear as a false component of the dc resistance measurement It is possible to eliminate
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