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9

HARS-LX Series

9

Maintenance

 

Chapter 5

MAintenAnCe

Maintainability and Reliability

5.1 

It is possible to maintain Model HARS-LX indefi

-

nately.  It is reliable due to its closed design and sealed 

switches and resistors.  It is possible to adjust the unit, 

if necessary, because it has 6 trimmable decades.  The 

unit is resistant to electromagnetic interference (EMI) 

because of its metal enclosure.

preventive Maintenance

5.2 

Keep the unit in a clean environment.  This will help 

prevent possible contamination.

The Model HARS-LX is packaged in a closed case 

and  uses  completely  sealed  switches. This  limits 

the entry of contaminants and dust to the inside of 

the switches.  If it is maintained in a clean or air-

conditioned environment, cleaning will seldom be 

required.  

Should cleaning be needed:

Remove the 4 housing screws from the side 

1. 

of the instrument, and remove the housing.

Remove  any  dust  or  debris  using  optical 

2. 

grade dry compressed air or a clean brush.

Replace the housing and reattach the 4 hous-

3. 

ing screws.

The front panel should be periodically cleaned to 

eliminate any leakage paths from near or around the 

binding posts.  To clean the front panel:

Wipe the front panel clean using alcohol and a 

lint-free cloth.

Calibration

5.3 

The Model HARS-LX may be employed as a stand-

alone instrument or as an integral component of a 

system.  If used as part of a system, it should be 

calibrated as part of the overall system to provide an 

optimum system calibration.

If the HARS-LX is employed as a stand alone device, 

the following should be observed:

Calibration Interval

• 

General Considerations

• 

Required Equipment

• 

Calibration Procedure

• 

Calibration interval

5.3.1 

The  recommended  HARS-LX  Series  calibration 

interval is twelve (12) months.  

If the instrument is used to transfer resistance values 

only, recalibration is not required, assuming that there 

has been no drastic change in the deviations of any 

individual resistors.

Summary of Contents for HARS-LX Series

Page 1: ...8438 FAX 516 334 5988 www ietlabs com 534 Main Street Westbury NY 11590 IET LABS INC HARS LX Series Laboratory Standard Decade Resistance Substituter User and Service Manual Copyright 2009 IET Labs In...

Page 2: ...PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT TEL 516 334 5959 800 899 8438 FAX 516 334 5988 www ietlabs com 534 Main Street Westbury NY 11590 IET LABS INC...

Page 3: ...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 shal...

Page 4: ...E 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...

Page 5: ...1 Thermal emf Considerations 6 4 4 Dial Setting 7 4 5 Power Considerations 7 4 6 Environmental Conditions 7 4 7 Switch Conditioning 7 4 8 Meter Shunt Applications 8 4 9 Kelvin Bridge Applications 8 Ch...

Page 6: ...ance Substituter 1 Figure 2 1 Typical Operating Guide Affixed to Unit 4 Figure 4 1 Kelvin Bridge Connections 8 Table 5 1 Trimming Potentiometers 12 Figure 5 1 Typical Trimmer Board 12 Table 5 2 Replac...

Page 7: ...anner no zero resistance subtractions have to be made and the accuracy given is for the absolute reading The HARS LX series employs completely enclosed dust tight very low contact resistance switches...

Page 8: ...term average value Leakage Resistance 1010 Resistance Temperature Coefficient 20 ppm C for 1 steps and under 15 ppm C for 10 steps 3 ppm C for 100 steps and over 50 C for wiring and switch resistance...

Page 9: ...1 111 1 4 0 01 HARS LX 4 0 1 1 111 k 4 0 1 HARS LX 4 1 11 11 k 4 1 HARS LX 4 10 111 1 k 4 10 HARS LX 4 100 1 111 M 4 100 HARS LX 4 1K 11 11 M 4 1 k HARS LX 5 0 001 111 11 5 0 001 HARS LX 5 0 01 1 111...

Page 10: ...4 HARS LX Series 4 Specifications Typical Operating Guide Affixed to Unit Figure 2 1...

Page 11: ...tandard temperatures near 23 C Repackaging for Shipment 3 3 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 man...

Page 12: ...tance 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 shoul...

Page 13: ...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 times nomianl maximum value can be obtained Power Co...

Page 14: ...resistance standard for all Kelvin bridge measurements When connected as shown in Figure 4 1 errors caused by lead and contact resis tances can be made negligible because they appear as part of the g...

Page 15: ...e the housing Remove any dust or debris using optical 2 grade dry compressed air or a clean brush Replace the housing and reattach the 4 hous 3 ing screws The front panel should be periodically cleane...

Page 16: ...s 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 measurement bridge...

Page 17: ...AUTION The HARS LX front panel should be connected to the test instrument s guard point Trimming Procedure 5 4 2 To trim any resistances proceed as follows Stabilize HARS LX at laboratory tempera 1 tu...

Page 18: ...ation 1 T0 or T1 2 T1 or T2 3 T2 or T3 4 T3 or T4 5 T4 or T5 6 T5 or T6 7 T6 or T7 8 T7 or T8 9 T8 or T9 10 T9 or T10 11 T10 or T11 100 k steps only Designation may vary for different dacades Trimming...

Page 19: ...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 Decade...

Page 20: ......

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