Fluke_8502A_Digital_Voltmeter_Option_04_Cal_Memory 电路图.pdf

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1、604-1. TNTRODUCTTON 604t . Installation of the Calibration Memory tnodule permits c.rtcnded calibration intervals while rnaintairring the accuracy of the instrument. A calibratiotr Iactor is entered into memory with a single keystroke. Calibration factors are determined bV comparison to a standard a

2、t the cardinal point for each function and range. An input of +1.000000V dc would be the cardinal point for the 1V dc range . A non-volatile memory allows storage of calibration factors for at least one year or until the instrument is conrplet ely recalibrated. 604-3. SPECIFICATIONS 604-4. DC Zero.

3、Ohms Zero, and calibration factors for the cardinal points of every range and function will be rnaintained for at ieast one year with no power applied tcr the instrumcnt. 604.5. INSTALLATION 601-6. Ref-er to Section 4 of this ntanual under-Module Installation and Removal for installaticln procedures

4、. The interconnect diagranr in Section 8 contains a table listing pernrissible and preferred slots. 604.7. OPERATING NOTES 604-8. When the Calibration Mernory module is installed. care nrust be exercised when using the instrument in the high resolution mode . Inadvertently depressing the STORE switc

5、h while in the higli resolution niode will erase the cal factor for that function and range from memory and enter an erroneous factor. Use the following procedure to enter calibration factors. 1. Ensure that the DC Zero and Ohms Zero proce- durcs have been pertbrmed. 2. Verify that the EXT REF and O

6、FFSET indicators are extinguished. 469684 8500 Series Option -04 Calibration Memory 3. Selcct the Cal rnode (CAL indicator illunrinated). 4. Select the desired function and range. 5. Apply an input li-orn a calibration sourcc equal tt.r tlie value of the cardinal point at the function and range seie

7、cted (e.g., with l0V dc selected apply + 10.000000V dc). 6. Depress the STOIE switch. The reading displayed shorrld be equal to the value of tlie input 1 thc listed specilication as long as the switch is heid in. 7. Repeat steps 4, 5 and 6 for each applicable funcr- tion and range. 8. Depress the RE

8、CALL switch to display the last uncorrected reading taken while in the Cal Mem- ory nrodc. The rcading is displayed until the switch is released. 9. fo renrove Calibration factors frorl the Cal Mern ory, use tl.re foregoing procedure, exccpt in step 5 use a short (an open fbr current factors) at the

9、 input terminals instead of the calibration sourcc. NOTE Correction Jarlors entered .for the V ac rms feature automatically correct any reading in dc cctupled ac. 604-9. THEORY OF OPERATION 604-10. The Calibration Menrory rnodule provides non- volatile read/write meurory used to store calibration co

10、n- stants and dc and ohnls zero f-actors. When the dc or ohms functions are selected, the appropriate zero factor (if one was entered) is broughl out by ihe instrunrent controlier lbr storage within the controller tnodule. Likewise. when a new function or range is selected. calibration constants are

11、 read frorn and stored fbr irnntediate use within the con- troller module. 604-i RadioFans.CN 收音机爱 好者资料库 8500 Series 604-ll. This rnodule was designed for use in more than one instrument. so there are lancl patterns attd sonte devices which are not uscd in this particuiar instruttterrt on thc pcb. T

12、he following discrrssion is keyed to the schemalic, Figure 604-1 . 604-12. RAM Location Addresses 604-13. R.AM location addresses are sent to tlre Caliblation Memorv module on the instrurncnt data bus. ID0-7. Address IC I , 2, 6 clocks the data into Ul3 through U I 5 -l 0. and U14-12. Outputs Irom t

13、I23 deterrline the location in the RAMs that data will be wlitten or rcad. 604-14. Write Operation 604-15. Addresses used in both read and write operations are true -l of 7 codes in wliich thrce lC lines must be high and four low to obtain a response. Writing data into ment- ory first requires an ad

14、dress (IC3,4,5 high) and a data kcy (lD 0. 3. 5, 6 high.ID 1,2,4,7 loiv) to set thc circuitry into tl.re write mode. The addrcss is decoded by Ul-5-9, U14-l ANDed by tll3-3 (VAl). Tl.re data kcy is decoded by 1124-1 3, U24-1 ANDed by U l3-4 (KEY). VAI arrd KIY are ANDed by U2-11 to produce the ACK r

15、esponse (Ui7, Ql) and to set Ul2-2 low (WRITE) through U25 10. The rnodule is now set into the write rnode. 604-16. The next address (1C0.2.6 high) is decoded by Ul5-6. Ul4-13 ANDed by Ul3-10 (VA2). V42 triggers a one-shot nrultivibrator, Ul-4, so U2-5,6 are both low and VA2WRITij is true (low) whic

16、h scls the RAMs into the write rnode. U12-l is high so U2-3 is high which disables the outputs of the RAMs (OD). Data to bc writte rr irtto the RAMs accompanies this address and is storcd in the rnetn- ory location previously clocked into U23. At terrnination of the addrcss. VA2 goes high clocking L

17、J12-l lorv and U12-2 high, which sets thc module into the read nrodc. 604-17. Read Operations 604-18. The module stays in thc read nrode unless set into the write rnode. Read operations requirc thc rddress resulting in VA2 as previously explained. This f irnc Llll-1 is low (READ). Ul-3 goes low enab

18、ling the RAM outputs. U2-4 is high sctting the RAMs (Ri$i ilto the read mode. The desired nremory location nrusi have been clocked into U23 prior to the READ address. 604-1 9. TROUBLESHOOTING 604-20. Problenrs in the Calibratiori Metttory can causc apparent problems in all functions o1lhc jnsirurnen

19、t. The rnost comrnon prclblerr is wrong valucs entcred. The recall feature may be used kr delernrine thc value of the storcd correction factor. Since correctioti tactors are rnultipliers, thc stored value wiil irc closc to one attd consc- quenily difTicult to display nrcaninglully. Instead. the last

20、 uncorrected reading is displayed wlren in the CAL mode, and the RECALL switch is depressed. Dividing thc 604-2 cardinai value fbr the selected range into the last uncrtr- rected reading lcsults in the stored constant. By using the recall feature. it is fairly easy to determine if a reasonable cal c

21、onstant is stored. 604-2 l. The threc lollowing checks may be rnade to deter- nrine if the (lalibration Me rnory is functioning properly. 1. Store zeros fbr all tunctions and rlnges, then recall the zero values. 2. Store cardinal points for all functions arrd ranges. then recall for the last uncorre

22、ctcd rcading. 3. Remove power for two or nittre hottrs (to ettsure that the RAMs have dischargcd C7 to the battery level), then reapply power and recall as in 1 and 2. This checks the shift of RAM power supply lront Vcc to battery and back to Vcc. The purpose of C7 is to rcrnove glitches in the RAM

23、supply whioh can scrarnble entrie s stored in RAM. 601-22. Table 604-1 lists the test points found on the Calibration Memory rnodule. Table 60.1 2 gives a symptonl analysis approach to troubleshooting. 604-23. PARTS LIST 604-21. Table 604-3 gives a parts breakdown ibr the Calibration Memory rnodule.

24、 Refer to Section 5 of this manual for ordering and use code information. Table 604-1. Test Points Table 604-2. Symptom Analysis TP1 - Vss; logic return, use as LO return for test instrument -fP2 - VA2. READ; low for the controller to read f rom cal mem- ory goes low 3 or 4 times every 200 msec TP3

25、- VA2 . WR ITE; low f or the controller to write into cal mem- ory goes low 4 times f or every STOR E s push TP4 - RAM Supply Voltage; when power is on =Vcc .6V when power is off = battery voltage TP5 - Negative Battery Terminal TP6 Vcc; Logic Supply TP7 - ACK; acknowledge signal returned when modul

26、e addressed SYMPTOMPOSSIBLE FAILURE Wont Store Wont Read Error at Turn-On Wrong Readings VA2 WRITE missing;check TP3 VA2 READ missing;check TP2 Battery voltage bad at TP4, RAM defective, not reading U23 (RAM address latch), RAM defective, wrong data stored RadioFans.CN 收音机爱 好者资料库 Table 604-3. Calibr

27、ation Memory Assembly REF DESIG OR ITEM NO. DESCRIPTION FLUK E STOCK NO. MFG FED SPLY CDE MFG PART. NO. OR TYPE TOT OTY REC OTY USE CDE BT1 BTI BTI C2 o C3 C4 C5 C6 C CRI. CR2 CR4 Qr Q3 Q4 Qs R1 R2, Rr I R4 thru R8, Rl2, Rl 5, Rl6, R2l, R22, R24, R25 R9 Rl0 Rl3 MEMORY ASSEMBLY (use whe n RlO i:i 408

28、2i16 448498 PPS092 r 96D474X0035 l.lAl DM I5F 18I J lc)6D334X0035 HAI l96Dl0-sx003-s JAI DMI5F391J I 960 I 06X 00r 5KA I I N4448 r N4448 MPS3640 168716 310072 2N3906 CRl5l-.15Pl5lT cRt5l -45P4737 (ii:5 I -45P I 0l T MFFl-81002F MFF r-8 r 303F MFF r-83402F I I I I I I I 3 REF I I I I I I ll G H 8500

29、Series 604-3 RadioFans.CN 收音机爱 好者资料库 8500 Series Table 604-3. Calibration Memory Assembly (Concluded) REF DESIG OR ITEM NO. DESCRIPTIOI FLUKE STOCK NO. MFG FED SPLY CDE MFG PART. NO. OR TYPE TOT OTY REC OTY USE CDE Rl4 R20 RNI, RN2 U U2 U3. U4 ut2,u22 ul3 u14 ul5 utl , u24 u23 u25 u_(:) LI21 u21 U9

30、U9 Res, nrf, 6.04k + 1%, I l8W Res. erl. dep. I k +57o. l/4W (use witlr LJc). Ull whcrr P/N 308757 is installed) Res Network O,a, Dgtl, TTL, 1o-pwr Schottky S f C. Dgrl. C-VlOS. qurd. J-input OR gares t!, Dgtl, C-MOS. dual complimentary pair pius lnverter Sta,Dgtl. C-MOS, 1024 bit, static RAM (use w

31、ith 408286) S,a, Dgtl, c-MoS. lo24 bit, static RANI (use with 4l 2890) (ttC, C-MOS. dual D type. flip-flop EtC,Dgtl, C-MOS, quad, 2-input NAND gates Sta,COS/MOS, dual 4-input NOR gates Sta,Dgtl, C-NOS, triple, 3-input AND gate Sta,Dgtl, C-MOS, dual4-inpur AND gate Sta,Dgtl, C-MOS, hex D flip-flop $f

32、C, Dgtl, C-MOS, hex, inverter/buffer StC,Dgtl, COSiMOS qual exclusive OR gate Case half, module Cover Moclule Case Decal, c;ii memory Guard, liont Guard, rear Shield, cover Socket, cornponent lead Socket, 1C,2.2 prn 285 I 89 343425 412908 404186 408393 4080i 3 129860 4081 51 340rr7 355198 363820 408

33、807 408199 404509 38 I 848 35s22.2 402990 402914 413484 383356 383364 4t t97 5 343285 4s3t26 91637 8003 l 89s36 01 295 1812s 02135 34649 34649 02135 0213s 0213s 02735 02735 12040 0273s 02135 89s36 89536 89536 89536 89.536 89536 00719 91 506 MFFl-86041F cR25 i.45P1027 412908 SN74LS 1 23N CD4O71 BE CD

34、4OOTAE P5101 L Ps r 01L-3 CD4Ol3AE CD4OI IAE CD4OO2AE CD4O73B CD4O82B MM74CI74N CD4O49AE CD4O3OAE 4029e0 402974 4t3484 3 833s6 383364 41r97 5 2-331212-6 322-AG39D 1 I I 2 2 I I I 2 1 I l 2 I I I I 1 2 2 2 2 I I I I I I 1 i I I I I I 1 604-4 Tp5 t TP3 TP+ nrl _/ _/ O-t:rts_l-l o6l AJ. .AJ. ldlplidl#l

35、lsl TT TTT r.l tl lir lil 14 ll trj ,a (-) L- FI L.J il TP6-R?6F o e,Gid0*u Ag . l;srrrrv i-J L-l _E- -ySor FrHfg.er,., cn+ / rzo RE orLy usso wrEi-iiiEi?Jr5x-idrEiEtr-iltditriiisuuo. E-af iilLL BE |NSTALLED l/|tFr uStNG LrrtruH BATTERY. A JUHPR WILL BE: IN5TALLED WITN USINS III-c:AD BATTERY. cAurro

36、N - THrS trH s|rorJLD rE tNSrAL!,D Duttle Tltlr I ro AvotD c.uFltNr DRA|N FRof BATTER,Wt|L coti,D OCCTJR DUE T-O INsTALLATION OF FAULTY COITIPc)IGI. ALL RES TSTOR /4W,CC,ALL REgTSTANCE rN OHMs. FOR REtr. DESTGNATION SEE 6500A. t76O FOR PCB DETAIL SgE Mt5-3160 FOR ASSY.DW6. SEF ASOOA-+t60. LAET REF. DE5. NOs USED: UZ5rO5,CRf,CJ,RNzrR23rBTl. VAZ . WRI +* 604.6 Figure 604-2. Calibration Memory (8500-1160) (t/zv)