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1、HARS-X SERIES High-Accuracy Decade Resistance Substituter User and Service Manual PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT Copyright 2002 IET Labs, Inc. HARS im/January, 2002 TEL: (516) 334-5959 (800) 899-8438 FAX: (516) 334-5988 IET LABS, INC. in the GenRad 534 Main Street, Westbury, NY 11590

2、 Standards Decades Strobes Sound Level Meters Bridges Tradition RadioFans.CN 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 iii HARS-X Series 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 specificati

3、ons. 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 speci

4、fications 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, INCLUD- ING BUT NOT LIMITED TO, ANY IMPLIED WARRA

5、NTY OF MERCHANTIBILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. RadioFans.CN 收音机爱 好者资料库 iv HARS Series Contents WARRANTY .iii Contents.iv Figures.iv WARNING .vi CAUTION .vi Chapter 1 INTRODUCTION.1 Chapter 2 SPECIFICATIONS. 2 Chapter 3 OPERATION. 5 3.1 Initial Inspection and Setup. 5 3.2. Connection.5

6、 3.2.1 General Considerations. 5 3.2.2 Electrical Considerations . 5 3.2.3 Four-Wire Kelvin Lead Connections.5 3.2.4 Thermal emf Considerations.6 3.3 Dial Setting . 6 3.4 Environmental Conditions.6 Chapter 4 MAINTENANCE .7 4.1Verification of Performance. 7 4.1.1 Calibration Interval . 7 4.1.2 Genera

7、l Considerations. 7 4.1.3 Procedure . 7 4.2 Schematic . 7 Figures Figure 1.1 HARS-X Series High-Accuracy Decade Substituter . 1 Figure 2.1 Typical Operating Guide Affixed to Unit . 4 Figure 3.1 Optimal 4-Wire Kelvin Lead Connection . 6 Figure 4.1 HARS Series Schematic Diagram. 8 v HARS-X Series WARN

8、ING OBSERVE ALL SAFETY RULES WHEN WORKING WITH HIGH VOLTAGES OR LINE VOLTAGES. ELECTRICAL SHOCK HAZARD. DO NOT OPEN CASE. REFER SERVICING TO QUALIFIED PERSONNEL. HIGH VOLTAGE MAY BE PRESENT WITH HIGH VOLTAGE OPTIONS. WHENEVER HAZARDOUS VOLTAGES ( 45 V) ARE USED, TAKE ALL MEASURES TO AVOID ACCIDENTAL

9、 CONTACT WITH ANY LIVE COMPONENTS: - USE MAXIMUM INSULATION AND MINIMIZE THE USE OF BARE CONDUCTORS. REMOVE POWER WHEN HANDLING UNIT. POST WARNING SIGNS AND KEEP PERSONNEL SAFELY AWAY. CAUTION DO NOT APPLY ANY VOLTAGES OR CURRENTS TO THE TERMINALS OF THIS INSTRUMENT IN EXCESS OF THE MAXIMUM LIMITS I

10、NDICATED ON THE FRONT PANEL OR THE OPERATING GUIDE LABEL. 1INTRODUCTION HARS Series Chapter 1 INTRODUCTION The High-Accuracy Resistance Substituter (HARS) series of resistance decade substituters is a family of instruments providing a very broad choice of high- performance resistance sources. Any nu

11、mber of de- cades from one to eleven is available in a choice of accuracies. The HARS substituter is a precision resistance source with excellent characteristics of stability, temperature coefficient, power coefficient, and frequency re- sponse. The HARS Series employs very-low-resistance switches w

12、ith silver alloy contacts. A special design keeps zero resistance to less than 1 m per decade. Self cleaning keeps the silver contacts from becom- ing tarnished when unused, or when only low cur- rents are passed through them. This is most often the case when only minute test currents are drawn by d

13、igital multimeters or other test instruments. Contact resistance is stable and remains low and repeatable. High-quality gold-plated tellurium-copper binding posts serve to minimize the thermal emf effects which would artificially reflect a change in dc resistance measure- ments. All other conductors

14、 within the instrument, as well as the solder employed, contain no metals or junc- tions that could contribute to thermal emf problems. The standard models offer a choice of one through eleven decades. The panels are clearly labeled show- ing the step size and maximum voltage and current limitations

15、 for each decade. With a resolution as low as 1 m and a maximum available resistance of over 111 M, the HARS se- ries may be used for exacting precision measurement applications requiring high accuracy, good stability, and low zero-resistance. They can be used as com- ponents of dc and ac bridges, f

16、or calibration, as trans- fer standards, and as RTD simulators. The HARS Series may be rack-mounted to serve as components in measurement and control systems. Figure 1.1. HARS-X Series High Accuracy Resistance Substituter 2SPECIFICATION HARS Series Chapter 2 SPECIFICATIONS For convenience to the use

17、r, the pertinent specifications are given in an OPERATING GUIDE affixed to the case of the instrument. Figure 2.1 shows a typical example. Accuracy: After subtraction of zero resistance, at 23C; traceable to NIST. HARS-X: (0.01% + 2 m) HARS-A: (0.05% + 2 m) HARS-Q: (0.02% + 2 m) Zero Resistance: 1 m

18、 per decade, at dc; slightly higher for 7-10 decades. Maximum Voltage to Case: 2000 V peak. Switch Type: 11 positions; 0-10; multiple solid silver alloy contacts. Switch Capacitance: 4 pF per switch, low-loss. Terminals: Low-thermal-emf beryllium-copper binding posts with standard 3/4 inch spacing,

19、plus shield terminal; connections on the rear of the instrument are available ( RO option). Single decade units have solder-terminal connections. SPECIFICATIONS ResistanceTotalStabilityLong TermTemperatureMax.MaximumMaximum perDecadeStabilityCoefficientPowercurrentvoltage StepResistance(ppm/year) (p

20、pm/3 years)(ppm/C)(W/step)(per decade)(per step) 1 m 10 m10070050 0.0255 A5 mV 10 m 100 m5035020 0.24 A40 mV 100 m 1 305020 0.251.6 A0.16 V 1 10 102520 0.60.8 A0.8 V 10 100 102515 0.60.25 A2.5 V 100 1 k10255 0.680 mA8 V 1 k 10 k10255 0.523 mA23 V 10 k 100 k10255 0.57 mA70 V 100 k 1 M 10255 0.5*2.3*

21、mA230 V* 1 M 10 M102510 0.5*0.7* mA700 V* 10 M 100 M254010 0.1*0.1* mA1000 V* *Subject to maximum of 2000 V. ModelDimensionsWeight 1 decade7.7 cm W x 7.7 cm H x 8.4 cm D0.45 kg (3 x 3 x 3.3)(1.0 lb) 2-4 decades 37.5 cm W x 8.9 cm H x 10.2 cm D1.7 kg (14.8 x 3.5 x 4)(3.8 lb) 5 decades2.0 kg (4.3 lb)

22、6 decades43.9 cm W x 8.9 cm H x 10.2 cm D2.2 kg (17.3 x 3.5 x 4)(4.8 lb) 7 decades2.4 kg (5.3 lb) 8 decades2.6 kg (5.7 lb) 9 decades48.3 cm W x 17.8 cm H x 19.7 cm D5.1 kg (19.0 x 7.0 x 7.8)(11.2 lb) 10 decades5.3 kg (11.7 lb) 3SPECIFICATION HARS Series Total Res. ( ) No. of Decades Model* (0.01% Ac

23、curacy) HARS-X-1-0.0010.0110.001 HARS-X-1-0.010.110.01 HARS-X-1-0.1110.1 HARS-X-1-11011 HARS-X-1-10100110 HARS-X-1-1001 k1100 HARS-X-1-1K10 k11 k HARS-X-1-10K100 k110 k HARS-X-1-100K1 M1100 k HARS-X-1-1M10 M11 M HARS-X-1-10M100 M110 M HARS-X-2-0.0010.1120.001 HARS-X-2-0.011.120.01 HARS-X-2-0.11120.1

24、 HARS-X-2-111021 HARS-X-2-101.1 k210 HARS-X-2-10011 k2100 HARS-X-2-1K110 k21 k HARS-X-2-10K1.1 M210 k HARS-X-2-100K11 M2100 k HARS-X-2-1M110 M21 M HARS-X-3-0.0011.1130.001 HARS-X-3-0.0111.130.01 HARS-X-3-0.111130.1 HARS-X-3-11.11 k31 HARS-X-3-1011.1 k310 HARS-X-3-100111 k3100 HARS-X-3-1K1.11 M31 k H

25、ARS-X-3-10K11.1 M310 k HARS-X-3-100K111 M3100 k HARS-X-4-0.00111.1140.001 HARS-X-4-0.01111.140.01 HARS-X-4-0.11.111 k40.1 HARS-X-4-111.11 k41 Resolution ( ) Single Decade HARS-X Unit SINGLE DECADE UNITS ORDERING INFORMATION Single-decade units are available with resistance as low as 1 m per step to

26、as high as 10 M per step. These units satisfy many system applications re- quiring only a single decade while maintaining all the quality features of the HARS series. Each decade is enclosed in an alumi- num case which can serve as a shield. It may be panel mounted and inte- grated with additional u

27、nits to form potentiometer circuits or other con- figurations. Each unit consists of low-inductance resistors in series, with a high-perfor- mance solid-silver-alloy-contact switch. * For less exacting applications, more economical tolerances are available: - use A for X in part number for 0.05% bas

28、ic accuracy, in lieu of .01% - use Q for X in part number for 0.02% basic accuracy, in lieu of .01% - use B for X in part number for 0.1% basic accuracy, in lieu of .01% OPTIONS - RMRack mountable case for standard 19 rack - KKelvin type 4-terminal binding posts - RORear output binding posts HARS-X-

29、4-10111.1 k410 HARS-X-4-1001.111 M4100 HARS-X-4-1K11.11 M41 k HARS-X-4-10K111.1 M410 k HARS-X-5-0.001111.1150.001 HARS-X-5-0.011.1111 k50.01 HARS-X-5-0.111.111 k50.1 HARS-X-5-1111.11 k51 HARS-X-5-101.1111 M510 HARS-X-5-10011.111 M5100 HARS-X-5-1K111.11 M51 k HARS-X-6-0.0011.111 11 k60.001 HARS-X-6-0

30、.0111.1111 k60.01 HARS-X-6-0.1111.111 k60.1 HARS-X-6-11.111 11 M61 HARS-X-6-1011.1111 M610 HARS-X-6-100111.111 M6100 HARS-X-7-0.00111.111 11 k70.001 HARS-X-7-0.01111.1111 k70.01 HARS-X-7-0.11.111 111 M70.1 HARS-X-7-111.111 11 M71 HARS-X-7-10111.1111 M710 HARS-X-8-0.001111.111 11 k80.001 HARS-X-8-0.0

31、11.111 111 1 M80.01 HARS-X-8-0.111.111 111 M80.1 HARS-X-8-1111.111 11 M81 HARS-X-9-0.0011.111 111 11 M90.001 HARS-X-9-0.0111.111 111 1 M90.01 HARS-X-9-0.1111.111 111 M90.1 HARS-X-10-0.00111.111 111 11 M100.001 HARS-X-10-0.01111.111 111 1 M100.01 HARS-X-11-0.001 111.111 111 11 M110.001 Total Res. ( )

32、 No. of Decades Model* (0.01% Accuracy) Resolution ( ) 4SPECIFICATION HARS Series CONSULT INSTRUCTION MANUAL FOR PROPER INSTRUMENT OPERATION HARS-X SERIES HIGH ACCURACY DECADE RESISTANCE SUBSTITUTER Temperature Coefficient:50 ppm/C for 1 m steps; 20 ppm/C for 10 m through 1 steps; 15 ppm/C for 10 st

33、eps; 5 ppm/C for 100 through 100 k steps; 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. IET LABS

34、, INC. 534 Main Street, Westbury, NY 11590 (800) 899-8438 (516) 334-5959 Fax: (516) 334-5988 HARSXCLBL/p1/HARS-X genl/10-00 CAGE CODE: 62015 5 OPERATION HARS Series Chapter 3 OPERATION 3.2.2 Electrical Considerations In order to make proper use of the full performance capabilities of the HARS-X unit

35、, especially if low resistance or low-resistance increments are impor- tant, care must be taken in connecting to the termi- nals of the decade box. In particular, in order to keep contact resistance to a minimum, the most substantial and secure connec- tion to the binding posts should be made. They

36、ac- cept banana plugs, telephone tips, spade lugs, alli- gator clips, and bare wire. The largest or heaviest mating connection should be made, and, where ap- plicable, the binding posts should be securely tight- ened. These considerations may be relaxed whenever single milliohms are considered signi

37、ficant for the task being performed. 3.2.3Four-Wire Kelvin Lead Connections Whenever possible, 4-wire Kelvin leads, the ideal connection, should be employed. Such a connec- tion minimizes the effects of contact resistance and approaches ideal performance. If the four terminals are available as clamp

38、s similar to alligator clips, they may be connected to the necks of the binding posts. If the four terminals are avail- able 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. 3.1 In

39、itial 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 3.2.1General Consider

40、ations The HARS-X Series Decade unit provides three terminals labeled H (high), L (low), and G (ground). The H and L terminals are connected to the ends of the resistance being set; the G terminal is connected to the case. The G terminal may be used as a guard or shield terminal. It may also be conn

41、ected (using a shorting link) to either terminal to allow two-termi- nal as opposed to three-terminal measurements. In order to make the most stable measurements, determine 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

42、 the more protected one of the two HARS-X terminals. That would ei- ther be the HARS-X terminal that is shorted to the case, or the LOW HARS-X terminal whenever nei- ther is connected to the case. 6 OPERATION HARS Series 3.2.4 Thermal emf Considerations The highest-quality low-ernf components are us

43、ed in the HARS-X Series. There nevertheless may be some minute thermal emf generated at the test leads where they contact the gold banana jacks. This emf will not reflect itself if an ac measurement instrument is employed. It will also be eliminated if a meter with so called “True Ohm” capability is

44、 used. Otherwise it may represent itself as a false compo- nent of the dc resistance measurement. 3.3 Dial Setting Whenever the dials are used in positions 0-9, the resulting resistance is simply read directly. Both the decimal point and the steps are clearly marked on the panel. For additional flexibility and range, each decade pro- vides a “10” position setting. This “10” position on any one decade equals the “