Manual - IET Labs, Inc.
Contents
1. 5 3 1 Initial Inspection and Setup 4 5 tre li io 5 3 2 Switch SetUlp rre NO 5 3 3 Connection to Terminals oder d Uere ro Er HEBR ROES 5 Chapter 4 Maintenance 7 4 1 Preventive Mainten tice oto mcer ree nd a Cn decer dh as 7 4 2 Calibration Interval russian said eph ae Gi 7 4 3 Considerations for Calibrations u L nn a n nuq ener enne 7 4 4 Calibration Proged re u sse enne nennen nnns 8 4 5 Capacitance Adjustment eene enne nnns 8 4 5 1 Adjusting 1 pF 1 000 pF decades 8 4 5 2 Adjusting 0 01 uF 1 uF decades 9 4 6 Replaceable Pattinson 10 Table of Contents ili HACS Z A 7E 1pF Figures and Tables Figure 1 1 mcsz E tpF a He rarHassrs siar 1 Figure 1 2 Capacitance Shunted by Leakage to case 2 Figure 1 3 HACS Z Construction as 2 Table 2 1 Specifications a 3 Figure 2 1 Double Shielded Construction 3 Figure 2 2 Typical Operating Guide Affixed to HACS Z 7E 1pF 4 Figure 3 1 Capacitance Shunted by Leakage to case 5 Figure 3 2 HACS Z Construction iii 6 Table 4 1 Capac lar Ype u 8 Figure 4 12. PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT HACS Z A 7E 1pF Decade Capacitance System User and Service Manual ED HACS Z SERIES 10 pF HIGH ACCURACY DECADE CAPACITANCE SUBSTITUTER Copyright 2010 IET Labs Inc Visit www ietlabs com for manual revision updates HACS Z A 7E 1pF im April 2010 O z I l3a l_sa s s s is a gt asasa6swy Wm wm lt shsas i as s I FSS s PTSS S FSF ZFZF06F6 S 6 72 1 LLLLLLLLLLULlLUb1LiLALA LLSeSACLILLB T LALZLLI L OZIOSLLLILLL AALALAXEGPz En os I l ET LAB S l NC www ietlabs com Long Island NY Email info ietlabs com TEL 516 334 5959 800 899 8438 FAX 516 334 5988 PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT O EEE EEE aa Ia a s_s 3asaa FFrrrF rrrr u uuauMuWuu ubuWrrrr l ET LAB S I NC www ietlabs com Long Island NY Email info ietlabs com TEL 516 334 5959 800 899 8438 FAX 516 334 5988 HACS Z A 7E 1pF Contents Chapter 1 Introduction uuu uu Uus asss a sassssausasaussssssaesssusassa 1 1 General Description IL nie rere i at e He REP cia ates 1 1 2 SS dI ETE 2 1 3 Double Shielded Construction essen 2 Chapter 2 Specifications nie 3 Specifications serian A a o e nr a ec a due 3 Double Shielded Construction essere 3 Chapter 3 Operation
3. is implemented with metallized poly phenylene sulfide MPPS These capacitors are hermetically sealed for high reliability and stabil ity Hermetic sealing prevents the intrusion of moisture into the capacitor packages and results in minimum drift Stability The stability of the capacitors 1s such that the in strument should not require readjustment for the duration of the recommended calibration interval Should recalibration become necessary easily ac cessible trimmer capacitors are provided for the 1 pF 10 pF 100 pF and 1000 pF decades The other decades may also be calibrated with discrete pad der capacitors HACS Z A 7E 1pF 1 2 Switches Custom designed switches are used to connect four capacitors In a parallel circuit for each decade These are weighted in a 1 2 2 5 code to provide all the necessary combinations for ten equal steps for each decade The switch circuit is designed such that each unused capacitor is completely disconnected from the rest of the circuit and has its positive terminal connected to the inner shield See Figure 1 3 The stability of the switches is assured by the use of large gaps and secure mechanical construction 1 3 Double Shielded Construction In order to meet the low residual capacitance require ment the unit utilizes Specially shielded and routed wiring The switching scheme described above and shown in Figure 1 2 A double shielded construction to keep the Zero capa
4. 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 INC CAGE CODE 62015 IET 534 Main Street Westbury NY 11590 516 334 5959 Fax 516 334 5988 www ietlabs com HACS Z lbls p1 HACS Z B 6E 1pF TMDE 06 16 09 80 Figure 2 2 Typical Operating Guide Affixed to HACS Z 7E 1pF HACS Z A 7E 1pF HACS Z A 7E 1pF Chapter 3 OPERATION 3 1 Initiallnspection and Setup This instrument was carefully inspected before ship ment It should be in proper electrical and mechanical order upon receipt An OPERATING GUIDE shown in Figure 2 2 is attached to the case of the instrument to provide ready reference to specifications 3 2 Switch Setting The HACS Z Precision Capacitor has six capacitance decades The actual capacitance for each decade is the product of the switch setting and the CAPACITANCE PER STEP indicated below each switch on the front panel Note however that if any dialis set on 10 a 1 is added to the next decade For example if the dials are set to 10 9 9 10 1 1 the resultant capacitance 1s 10 Total 1100011 pF The zero capacitance of the HACS Z unit is very low but all settings are adjusted to accurately provide their nominal values and it is not necessary to subtract the Zero capacitance from any particular setting Operation 3 3 Connection to Termin
5. ACS Z A 7E 1pF Chapter 2 SPECIFICATIONS For convenience to the user the pertinent specifications are given in an Operating Guide similar to the one shown in Figure 2 2 which is affixed to the case of the instrument riled Aras p EA step Erz pacitance EIN 10 0p lt 0 002 002 Air capacitors Position 1 0 002 Position 1 0 001 inF 500 V peak max up to 10 kHz Position 2 0 0005 200 ppm 0 1 pF All others 0 0003 per year i 0 05 0 5 pF Ses Silvered mica 1 000 pF ERE lt 0 0003 Mechanically stabilized oop 100 nF 0003 Hermetically sealed OF tr 0004 Sealed metallized polyphenylene nm 10 pF 50 V peak max 0 0010 500 ppm per year sulfide MPPS Bottom terminals for all decades 1 kHz 3 terminal measurement series model 1 Vrms 23 C traceable to SI No zero subtraction required Table 2 1 Specifications Range Dimensions 0 to 11 111 110 uF in 1 pF steps 54 cm W x 32 cm H x 33 cm D 21 x 12 5 x 13 Zero Capacitance Weight lt 0 1 pF maximum capacitance obtained with all dials set to zero 23 kg 51 lbs Temperature Coefficient Connection to Capacitor 1 pF 0 1 nF decades 20 ppm C Four bnc connectors labeled HI and LO located on the front The 1 uF decade 50 ppm C shielding is divided into the following parts Insulation Resistance The inner shield minimizes the terminal to guard capacitance 50 000 MQ Outer shield the case minimizes the detect
6. Calibration access MONOS un aa ee 8 Figure 4 2 Screws holding the internal housings 9 Figure 4 3 0 01 pF amp 0 1 UP capacitance sets cestas iia 9 Figure 4 4 1uF Capacitance Set 9 Table 4 2 Replaceable Paris List 10 Figure 4 5 Replaceable POIs siepe treo A al 10 iv Table of Contents Chapter 1 HACS Z A 7E 1pF INTRODUCTION 1 1 General Description The HACS Z 7E 1pF Decade Capacitance System 1s capable of meeting exacting requirements for fixed or adjustable calibration capacitance or any applications requiring precise stable capacitance values Unit Features Range pF 11 111 11 uF Low zero capacitance High accuracy Excellent stability Low temperature coefficient High voltage rating a pr mon ACCURACY DIA CAPAGTANCL SUBSITUTUL ed D oe e ac e oe A ame BS Figure 1 1 HACS Z 7E 1pF Introduction 1 pF 10 pF decades For these the lowest decade steps trimmable air capacitors are used The capacitors are selected for maximum resolution high mechanical stability and low dissipation factor 100 pF 0 1 uF decades These mid range decades are implemented with the highest grade mechanically stabilized sealed India ruby mica capacitors selected for optimum electrical characteristics and low dissipation They are hermetically sealed to prevent intrusion of moisture and to obtain minimum drift 1 pF decade This decade
7. als In order to properly use the HACS Z capacitor it is necessary to understand the use and function of each of the capacitor terminals Refer to Figure 3 1 and note that a basic capacitor is a 2 terminal capacitor shown as C As described above C and C the capacitances to the case add to the capacitor C un less the 3rd terminal G is connected to the guard of the measuring instrument C HIGH LOW G Figure 3 1 Capacitance Shunted by Leakage to case HACS Z A 7E 1pF The shielding is divided into two different parts an inner shield that minimizes the low terminal to guard capacitance and an outer shield the case that minimizes the detector input capacitance and noise See figure 3 2 INNER SHIELD OUTER CASE Figure 3 2 HACS Z Construction When these two shields are connected together the HACS Z becomes an excellent 3 terminal capacitance substituter with low zero capacitance Using the unit as a 2 terminal capacitor will cause an error of about 100 to 150 pF to be added This error is not necessarily the same for every setting This also makes the unit susceptible to noise However for high capacitance the unit may be used as a 2 ter minal device Operation HACS Z A 7E 1pF Chapter 4 MAINTENANCE 4 1 Preventive Maintenance Keep the unit in a clean environment This will help prevent possible contamination The HACS Z is packaged in a closed case which limits the entry of contami
8. citance at an extremely low level Figure 1 2 demonstrates the need for the double shielded construction It shows that a capacitor C would be shunted by the series combination of the series combination ofthe capacitances from the HIGH and LOW terminals to the case The net capacitance becomes C C in series with C Clearly it would be very difficult to get a very low residual or zero capacitance unless the G terminal is the ground terminal of 3 terminal measurement of the capacitance In order to accomplish this an inner shield 1s added as conceptually shown in Figure 1 3 It is mechani cally constructed to shunt away any capacitance between the HIGH and LOW terminals This inner shield shunts this capacitance when it is electrically connected to the outer shield forming a 3 terminal capacitor 5 teminal capacitor for units with 10 uF steps or higher All unused capacitors are shorted to this inner shield at their high ends and are open at their low ends This inner shield is not actually an internal enclosure but rather a cellular structure that optimally separates all conductors and capacitor elements It also serves to minimize terminal to ground capacitance which is necessary when measuring small capacitances with various bridges C HIGH LOW SNS ve G Figure 1 2 Capacitance Shunted by Leakage to case HIGH LOW INNER SHIELD OUTER CASE Figure 1 3 HACS Z Construction Introduction H
9. nants and dust into the instru ment If it is maintained in a clean or air conditioned environment cleaning will seldom be required In a contaminated atmosphere cleaning may be required To clean the front panel wipe the front panel using alcohol and a lint free cloth 4 2 Calibration Interval The recommended calibration interval for the HACS Z Capacitance Substituter 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 Iftheuser should choose to perform this procedure then the considerations below should be observed Maintenance 4 3 Considerations for Calibration Itis important whenever calibrating the HACS Z unit to be very aware of the capabilities and limitations of the test instruments used Recommended Instruments ET Model 1689 Digibridge direct reading or ET Model 1620 or 1621 Precision Capacitance Measurement System bridge The test instruments must be significantly more accu rate than 0 05 0 5 pF for all ranges allowing for a band of uncertainty of the instrument itself It is important to allow both the testing instrument and the HACS Z to stabilize for a number of hours at the nominal operating temperature of 239C and at nominal laboratory conditions of humidity There should be no temperature gradients across the unit under test BNC test terminals should be
10. or input capacitance and noise Operating Temperature Range The outer shells of the HI connectors are connected to the switch shaft 10 C to 40 C The outer shells ofthe LO connectors are connected to the outer case Shielding To use the HACS Z as a 3 terminal capacitance substituter with Double shielded construction see below very low zero capacitance connect the two shields together at the measuring instrument DOUBLE SHIELDED CONSTRUCTION The shielding is divided into two different parts an inner shield that minimizes the low terminal to guard capacitance and an outer shield the case that minimizes the detector input capacitance and noise See Figure 2 1 Inner Shield When these two shields are connected together the HACS Z becomes an excellent 3 terminal capacitance substituter with low zero capacitance Outer Case Figure 2 1 Double Shielded Construction Specifications 3 Specifications HACS Z A 7E 1pF HIGH ACCURACY DECADE CAPACITANCE SUBSTITUTER CONSULT INSTRUCTION MANUAL FOR PROPER INSTRUMENT OPERATION Range I Capacitance 0 to 1 111 10 pF in 1 pF steps per step Zero capacitance 0 1 pF maximum capacitance obtained when all dials are set to zero Temperature coeficient 20 ppm G Insulation resistance gt 50 000 MQ Operating temperature range 10 C to 40 C Total decade capacitance dp oF Position 1 0 001 1nF 500 V peak maxup Position 2 0 0005 All
11. others 0 0003 to 10 kHz 0 05 0 5 others lt 1000pF vo pF 0 001 pF wor od tur 50 V peak max 10 uF lt 0 0010 Dissipation factor lt 0 002 Position 1 0 002 Allothers 0 001 Stability Capacitor type Air capacitors did Er accuracy Silvered mica M echanically stabilized Hermetically sealed 200 ppm 0 1pF per year lt 0 0005 lt 0 0003 lt 0 0004 Sealed metalized polyphenylene sulfide MPPS 1kHz 3 terminal measurement series model 1 Vrms traceable to SI No zero subtraction required Connection to capacitor Two bnc connectors labeled HI and LO are located on the front panel The shielding is divided into the following parts The inner shield minimizes the terminal to guard capacitance The outer shield the case minimizes the detector input capacitance and noise The outer shell of the HI connector is connected to the switch shaft The outer shell of the LO connector is connected to the outer case To make the HACS Z a 3 terminal capacitance substitutor with very low zero capacitance connect these two shields together at the measuring instrument MODEL HACS Z A 7E 1pF SN H1 1015332 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
12. used to obtain accurate shielded readings HACS Z A 7E 1pF 4 6 Replaceable Parts o MAGSZ4xOKNS Knob Assombiy HIGH bnc connector Table 4 2 Replaceable Parts List Figure 4 5 Replaceable Parts 10 Maintenance HACS Z 10E 1pF 11
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