IET Labs RS-925D, User And Service Manual

Page 1: ...www ietlabs com IET LABS INC Email info ietlabs com Precision instruments for test and measurement RS 925D Resistance Standard User and Service Manual Copyright 2014 IET Labs Inc Visit www ietlabs com...

Page 2: ...ruments for test and measurement IET Model RS 925D This RS 925D is the IET Labs version of the original esi RS 925D Decade Resistance Standard The IET unit is updated and features a number of signific...

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Page 5: ...ermal emf Considerations 5 4 3 Dial Setting 6 4 4 Rheostat Operation 6 4 5 Power Considerations 6 4 6 Environmental Conditions 7 4 7 Switch Conditioning 7 4 8 Meter Shunt Applications 7 4 9 Kelvin Bri...

Page 6: ...al Operating Guide Affixed to Unit 3 Figure 4 1 Rheostat Dial 6 Figure 4 2 Rheostat Schematic 6 Figure 4 3 Kelvin Bridge Connections 7 Table 5 1 Trimming Potentiometers 11 Figure 5 1 Typical Trimmer B...

Page 7: ...e reading The RS 925D Resistance Standard employs com pletely enclosed dust tight very low contact resistance switches They feature solid silver alloy contacts and quadruple leaf silver alloy wipers w...

Page 8: ...1 10 ppm 5 ppm typical 10 k 100 k 10 mA 5 W 3 0 1 100 k 1 M 3 mA 2 000 V peak 3 0 1 Wiring and switch resistance NA 50 C 0 2 W NA At 23 C true ohm measurement 30 70 RH absolute reading SI traceable N...

Page 9: ...r Decade positions Resistor type whichever applies fi rst 100 division 20 resolution 10 m 2 A NA 20 1 20 ppm 0 5 m Continuous Rheostat 1 m 10 m 2 A NA 20 1 11 positions 0 10 Resistance wire 10 m 100 m...

Page 10: ...ard temperatures near 23 C 3 3 Repackaging for Shipment If the instrument is to be returned to IET Labs contact the Service Department at the number or address shown on the front cover of this manual...

Page 11: ...sistance or low resistance increments are important care must be taken in connecting to the terminals of the decade box In particular to keep contact resistance to a mini mum 4 terminal connections sh...

Page 12: ...etting in the next decade into consideration To get 1 000 for example the switches should be set to show 0 9 10 0 Since the highest decade has an additional 11 po sition resistance values of over 1 2...

Page 13: ...connected to the current source 2 Determine the current by the ratio of the mea sured voltage to the known resistance Using the 4 terminal technique helps avoid errors caused by the voltage drops in t...

Page 14: ...e housing 2 Remove any dust or debris using optical grade dry compressed air or a clean brush 3 Replace the housing and reattach the 4 hous ing screws The front panel should be periodically cleaned to...

Page 15: ...follow ing models HATS LR HATS Y SRL Series The 1 and 10 transfer standards are optional and are only used to take advantage if desired of the trimmability of these two decades Precision resistance me...

Page 16: ...TION The RS 925D front panel should be connected to the test instrument s guard point 5 4 2 Trimming Procedure To trim any resistances proceed as follows 1 Stabilize RS 925D at laboratory temperature...

Page 17: ...er Designation All decades but 1 k Potentiometer Designation 1 k decade 1 T0 T1 2 T1 T2 3 T2 T3 4 T3 T4 5 T4 T5 6 T5 T6 7 T6 T7 8 T7 T8 9 T8 T9 10 T9 T10 11 T10 1 M steps only Table 5 1 Trimming Poten...

Page 18: ...HARS 4000 LX 0 1 100 m step Decade Switch Assembly Not Shown HARS 4000 LX 1 1 step Decade Switch Assembly Not Shown HARS 4000 LX 10 10 step Decade Switch Assembly Not Shown HARS 4000 LX 100 100 step...

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