HP 3484A Service manual

MODEL 3484A
MULTIFUNCTION UNIT

OPERATING AND SERVICE MANUAL
MODEL 3484A
MULTIFUNCTION UNIT
-hp- Part No. 03484-90000
Serials Prefixed: 975-
Copyright Hewlett-Packard Company
1970
P.O. B ox 301, Loveland, Colorado, 80537 U.S.A.
Printed: JULY 19 70

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333 Logue Avenue
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Mou ntaln V i ew , Call f orn la 9"40"40
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r Model 3
484A
Table of C on tents
TABLE OF CONTENTS
Section Page
l. GENERAL INFORMATION ................ 1-1
1-1 . Introdu ction ............ . ........... 1-J
1-2. Opti ons ........ .................... 1-1
1-3. Isolated Remote Option 041 . . . . . . . . . . 1-1
1-4. Ohms Converter Opti
on 04 2 .......... 1 -1
1-5. True RM S Conv erter Opti on 04 3 ....... 1-1
1
-6 . Specifications .... ......... . ......... 1-1
1 -7 . In st rume nt and Manual Identification .... 1 -1
1 -8 . Accessory Equipment Available . . . ... ... 1-1
Section Page
II . INSTALLATION .. .. .. . ............ . ..... 2-1
2-1. Intr od uction ........................ 2-1
2-2. Initial Inspection
.................... 2-1
2-3. In
sta llation . . . . . . . . . . . . . . . . . . . . . . . . 2 -1
2-4. In sta ll at i on of Isol at ed Re mot e
Option 041 ....................... 2-1
2-5. In
st allation of Ohms Co nv ert er
Option 042 ............. . .. . ...... 2-1
III. OPERATING INSTRUCTIONS .............. 3-1
3- 1. Introdu ct ion .. . ... ..... ......... . ... 3- 1
3-2. Front and Rear Panel Descripti on ........ 3-1
3-3. Functi
on Selection ................... 3-1
3
-4 . Range Selecti on ..................... 3-1
3-5. Automatic Ranging .. ......... . ..... 3-1
3-6. Re
mote Range Selection . . ........... 3-1
3-7. Sample Co
nt rol ...................... 3-1
3-8. Automat
ic Sampling . . . ... . ......... 3-1
3-9. Manu
al and Re mot e Sample Control .... 3-1
3- 15. R emote Tri gge ring Rat e . . . .. ......... 3-2
3- 1 8. Inter face Ho ld ..................... 3-2
3- 19. R emo te Programming ... . ... . ..... .. . . 3-3
3- 20 . Standard Re mot e Programming ........ 3-3
3-21. Isol
at ed Remote Option 041 .......... 3-3
3-26. R
emo te Program Connec ti on . .. ..... .. 3-4
3-
27. Guard Connection ..... .. . .... . .... .. 3-5
3-32. DC Voltage
Me as urements ............. 3-5
3-33. Filter Selection
.................... 3-5
3-34. R
es ponse Time .... .......... .... . . 3-5
3-36.
Mea suring Speed ....... . ........ . .. 3-6
3-37. DC Volta ge Mea surement Pro ced ur e .... 3-6
3-38. Resistance Measurements (Option
042) . . . 3-6
3-39. Filt
er Selection . . . . . .... .. ..... .. . . 3-6
3-40. Response Time . . . . . . . . . . . . . . . . . . . . 3-6
3-
41. Autoranging Time . .... .. ... . . . ..... 3-6
3-42. Measuring
Sp eed ................... 3-6
3-43. Ohmmeter Curr en t ... ..... . ... . .. .. 3 -6
3-44. Low Resis tanc e Meas ur ements ......... 3-7
3-45. R
es i sta nce Meas ur eme nt Procedure ..... 3-7
3-46.
AC Volta ge Measurements (Opti on 04 3) . . 3-7
Sect io n III.(Co nt'd)
Page
3- 47 .
3-48.
3-51.
3-52.
3-53.
3-54.
Section
AC or DC Coupled Measureme nt ....... 3 -7
Maximum I nput Voltages . ... . . ... . .. 3-7
Response Time .
.. . . . ... . . ... ... .. . 3 -7
Measuring Speed ........... . . ...... 3-7
Auto
ra nging Time .................. 3 -7
AC Voltage Measurement Procedure .... 3-7
Pa ge
IV. THEORY OF OPERATION ......... . . . .... .. 4-1
4-1.
4-2.
4-3.
4-4.
4-5.
4-10.
4-11.
4- 12.
4-16.
4- 17.
4-23.
4-26.
4-27.
4-31.
4-32.
4-45.
4-49.
4-52.
Section
Introdu ct ion ........................ 4-1
DC Circuits
.. . . .... . .......... . ... . . 4-1
I nput Att enu ator ..... . ............. 4-1
Feedba
ck Attenuator .... . ... . . . . .... 4-1
DC Amplifier ...... . . . ........... . . 4-3
Variable Filt er a nd Filter Amplifier ..... 4-3
Manual
and Remo te Filter Selection . ... 4-3
Fu n ctio n Selecti on Circui ts ............ 4 -4
Ran ge Selection Circuits ............... 4-4
Aut ora nge Control . . . . . . . . ... .... ... 4-4
Range Register
..................... 4 -5
Range Register Decod in g . . . . . . .... . . . 4-5
R
emo te Range Selection ... .......... 4-6
Manual Range Sel
ect i on .. . . . . . . ... . .. 4-6
Delay Generator and Sample Control
Circuits .
......................... 4-6
Isolated R
emote Option 041 ........... 4-8
Ohm s/ DC Converter Opti on 042 ........ 4 -9
T rue RMS AC Converter Opt io n 043 . .... 4-9
Page
V. MAINTENANCE ......................... . 5-1
5-1. In
troduc ti on .......... .. ............ 5-1
5-2. Test Equipment Required
... . . . . .. .. ... 5-1
5-3. Performance Checks .................. 5-1
5
-4 . VDC Accuracy and Lin ea ri ty Check .... 5-1
5-5. VDC Input Resistance Check . .
... . .. .. 5-2
5-8. DC Common Mode Rej
ec tion Check .... 5-3
5-9.
AC Common Mode Rejection Ch eck .. .. 5-3
5- 10 . AC Normal M ode Rejection Check ..... 5-4
5-11. Ohmm eter Accuracy Ch eck ........ ... 5-5
5-12. V
AC Accura cy (Option 043) . .... ... . . 5-5
5-1
3. Adjustment Procedures ................ 5-5
5-1
6. DC Amplifier Zero a nd Off set
Adjustme nt s ........ .... ..... . ... . 5-5
5-J 7. DC Amplifi er Gain Adjustments ....... 5-7
5-18. DC
Att enuator Adjustme nt . . .... ... . . 5-7
5-19.
Ohm s Converter Adjustments(Option 042)5-7
5-22. Tru e RMS AC Converter Adjustments ... 5-8
5-23. Servicing Information
............ . .... 5 -8
5-24. Clean Handling Techniqu es ........... 5-8
5-28. Reed Replacement
........... . . . . . . . 5-9
5-31. DC Amplifier Assembly Repair
and
Ex change ............ . ............ 5-9
iii

Table of Contents
Mod el 3484A
TABLE OF CONTENTS (Cont ' d)
Section V. (Cont'd) P age
5-34.
5-35.
5-36.
5-37.
5-41.
5-42.
5-47.
5-53.
5-56.
5-58.
5-59.
5-60.
5-61.
Troubleshooting
....... ...... ........ 5-10
DC Amp li fi er Zero Offset ............ 5-1O
DCV Di splay Limiting .. . .. .......... 5-10
DC Amplifier Gain Errors ............ 5-10
DCV Reed Relay Checks ............. 5 -1 1
Ran
gi ng Ch ec ks .................... 5-11
Delay Generator Ch ec ks . .......... .. 5-11
Isolated Remote A
sse mbly, Option 041 .. 5 -1 3
Ohms Co nv erter, Option 042 .......... 5-13
Factory Selected Components
.......... 5 -14
DC Amplifier A sse mbly A2 ........... 5- 14
A6R7* . . .
........................ 5-14
A6R25*
.............. .. .......... 5- 14
Section Pa ge
VI. REPLACEABLE PARTS . . . . . . . . . . . . . . . . . . 6-1
6-1. introduc ti on ........... .... ........ 6-1
6-4. Orderi ng Information .......... ...... 6-1
6-6. Non-Listed Parts . ....... ........... . 6-1
Se ction P age
VI I. CIRCUIT DI AGRAMS . . . . . . . . . . . . . . . . . . . . 7-1
7-1. Introduction ...... ........ . . ...... . 7-1
7-2. Not es ........... . ................ 7-1
Appendic es
A. C ODE LIST OF MANUFACTURERS
B. SALES AND SERVICE OFFI CES
LIST OF TABLES
Number Page Number
Pa ge
1-1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 -2
3-1. Delay and R es ponse Tim es .............. .... 3-2
3-2. Interface Signals . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3-3. Ohmmeter Current
.. ....... ...... ...... . . . 3-6
4-1.
DC Volta ge Ran ge Relays . . ...... . .......... 4- 1
5-1. Required T
es t Eq uipment ................... 5-0
5-2. DCV Ac curacy a nd Lin ea rity Check .......... . 5-2
5-3. Ohmmeter Accuracy Check ................. 5-5
5-4 . DC Amplifier Gain Errors .................. 5-10
5-5. DCV Recd Relay Ch ec ks ............... .... 5- 12
5-6. Delay Timing .
... .... ... ...... ........ .. 5-13
4-2.
Lo gi c Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 -2
5-7. Ohms Converter Reed Relay Checks .......... 5-15
4-3. Range Register Content
.... . . . ............. 4-5 6-1. Re
pl aceable Parts ...... . . .. ......... . . . ... 6-2
LIST OF ILLUSTRATIONS
Number Pa
ge
1- l. Model 3484A M ul ti fun ction Unit . ..... . ... ... I-1
2-l . Plug
-in Draw er Installati on and Removal ....... 2-2
2-2. I so lated Remote Option Installation . . . . . . . . . . . 2-3
2-3
. Location of Switch Limit Stops .............. 2-3
3-1. Front and Rear Panel . . . . .................. 3 -0
3-2. External Trigger Connections ................ 3-2
3-3. Remote Connector JJ4
........... .... ...... 3-3
3-4. Isolated Remote Program Sequence
..... ...... 3-4
3-5. Guard Connection . . . . . . . . . . . . . . . . . . . . . . . . .
3-5
4-1. Simplified Bl ock Dia gra m ........... ... . .... 4-1
4-2.
Sim plified Diagram, DC Amplifier ............ 4-3
4-3. Autoran
ge Control Circuits . . ................ 4-4
4-4. Simplified Range R
egis ter D ia gra m ...... ...... 4 -5
4-5. Remote Selection of Hi ghest Ran ge ........... 4 -6
4-6. Delay Generator Block Dia gram .............. 4 -7
4-7. Del ay and External Tri gger Gating ... . ........ 4 -8
4-8. Isolated Remote Pro gr am Circu it ....... ...... 4-8
4-9. SimpUfied Ohmmeter
Di agram ............... 4 -9
4-10.True RM S Conve rt er Block Diagram ........ . .. 4-9
5-
1. VDC Accu ra cy Check ... . . ................. 5-1
5-2. Input R es istance Check . . . . . . . . . . . . . . . . . . . . . 5-2
5-3.
DC Common Mode Rejection Check ........... 5-3
5-4. AC Common Mode Rejection Check . . . . . . . . . . . 5 -4
5-5. AC Normal Mode Rejection Ch eck . . . . . . . . . . . . 5 -4
iv
Number
Pa ge
5-6. Lo cation of Adj ustments .... ......... .. . ... 5-6
5-7.
Co mponent Re pl acement ................... 5-8
5-8. R ee d Removal and Replacement ............ . . 5-9
5-9. DC Amplifier Diagram .................... 5- 11
5-10. DC Amplifier Input Connections .......... .. 5-13
5- 11.Ohms Converter Resistances ................ 5 -14
5-12. DC Zero Offset Troubleshooting Tr ee ....... . . 5-17
5-13.Limi
te d DC Di s pla y Troubl es hooting Tr ee ... .. 5- 19
5-14.Autoran
gc Troublesh oot ing . . .. ... . ........ 5-2 1
6-1. Location
of Mi sce ll aneous Parts ...... .... ... 6-12
Schematic s and Diagram s
7- 1. Location of Ass emblies . . . ... ... ............ 7-2
7-2.
Blo ck Di agr am ........................... 7-3
7-3. DC Attenuator a nd Amplifi er ................ 7-5
7-4. Ran gi ng Circu it s .......................... 7-7
7-5. Function Circuits ....................... .. 7-9
7-6. Isolated Remote Option 041
................ 7- 11
7-7. Ohms Converter Option 042 ........... ..... 7- 13
7-8. Connections to
Ran ge and Function
Asse
mb ly A3 .................... . ...... . 7-15
7-9. Plug-in Co
nn ect or Pl2 and Remote
Co
nn ector 114 ... . . ...... . ............. . 7-17
7- 10 .Ground Co nn ections .............. .. ...... 7- 19
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Model 3484A
S ec tion I
SECTION
GENERAL INFORMATION
1-1. INTRODUCTION.
The ·h p· Model 3484 A Multifunc tion Unit , in con ju nction
with either the Model 34 80 A or 3480 B Digital Vol tmete r,
makes 4-digit de vo
lt age meas ur ements, with up to 50 %
overrange capability. Full scale ranges of I 00 mV,
IOOOmV, lOV, IOOV , and IOOOV may be selected
manually,
automatically, or remotely. Polar ity sele ct i on
and display arc automatic. The degree of filtering desired
may al
so be sel ec ted manually or remotely. Resistance and
true rm s ac voltage measurements may be made if Op tions
042 and 043 are added.
1- 2. OPTIONS .
1-3.
ISOLATED REMOTE OPTION 041.
Opti on 041 provides re mot e programming con n ectio ns
which are isolated
from th e Model 34 84 A int ernal circuits.
All
external co nne ct ions arc referenced to chassis (power
lin e) gro und. This o ption is available for field installation as
-
hp - Model 111 51 A, I solated R emo te Assembly. Opti on
041 c anno t be used unless th e Model 3480 A/B is eq u ipped
with I solate d BCD Output Opti on 004.
1- 4. OHMS / DC CONVERTER OPTION 042 .
Opti on 042 allows the M ode l 3484A to make resistance
measurements
on six ranges of I 00 n, 1000 n, 10 kS1,
100 kS1, 1000kS1 , and JOMS1 full scale, with up to 50%
overrange capabili ty . Ran ge may be selected manually,
automatically, or remotely. This op ti on is available for field
installation as -hp- M
ode l l l l 52A, Oh ms/DC Converter
Assembly.
1- 5. TRUE RMS AC CONVERTER OPTION 043 .
Option 043 allows th e Model 3484A to make true rms ac
voltage measurements on five ranges of 100 mV, 1000 mY,
34 114 A MU LTIFUNCTION UNIT
FUNCTION RANGE
SA M P ~ RATE~
HOU).Jli'
T111a ZCRO
@ •
J OY, lOOV, and IOOOV full scal e, with up to 50%
overrange capability. Ran ge may be selected manually,
automa ti ca lly, or remote ly . This opt ion is available for fi eld
in
sta ll ation as -hp- Model 11 I53A, True RMS AC Convert er
Assembly.
1-6. S PECIFICATIONS .
Comp lete specifications for the Model 3484A and 348 0A /B
combinat i on are given in Table 1 -1 .
1-7. INSTRUMENT AND MANUAL IDENTIFICATION.
Hewlett-Packard uses a two-section serial number. If th e
first section (serial
prefix) of the serial number on yo ur
instrument does not agree with those on the title page of
this man ual, change sheets supp lied with the manual will
define
the differences be tw een your instrument and th e
Model 3484 A described in this manual. Some serial
numbers may have a letter separating t he two sect ions of
the number. This l ette r indi ca tes the co unt ry in which the
instrument was manufa ctu r ed.
1-8. ACCESSORY EQUIPMENT AVAILABLE.
1-9. The M ode l 1 I I 48A Plug-in Extender Cab le allows
the plug-in unit to operate ou tside the 3480 A/B to
fac ili tate servicin g.
1· 10 . The Model 1114 9A R emo te Programm in g Cable is 6
feet Jong
and is t er minat ed at one end by a co nn ecto r
which mates with the 3484A rear panel remote connector
Jl4. The o th er end of the cab le is unterminated.
1-11. For additio nal inform ation regarding optio nal eq uip -
ment , contact your ne arest -hp- Sales and Service Office,
listed in Appendix B.
FILTER
TE RMINAL
Fi g ur e 1-1. M ode l 3484A Multifunc ti on Unit.
1-1

Section I
1·2
Model 3484A
Tab le 1-1. Specificat ions.
The following specifications app ly to the Model 3484A Multifunction Unit used in the Mod el 3480A /B Digital Vo l tmete r.
DC VOLT S
Full Scale V
ol tage Ra n ges
50% Overrange capability on all ranges;
maximum input ± 1 200 V.
Range Selection
Automatic Ranging
Polarity Sel ection and Di sp lay
Vo ltage A ccuracy
24 hours (23°C ± 1°c, less than 50 %
relative humidity)
90 days (25°C ±s0 c, le ss than 95 %
relative humidity)
Temperature Coeffic i ent
o0c to 55°c
Mea su rin g Speed
Read ing Period
Reading Rate (without range change)
Automatic
Manual Trigger
External Trigger
Response Time
Autorange Time
100 mV, 1000 mV, 10 V, 100 V, 1000 V
Manual, Automati c, or Remote
Upranges at 140 % of range
Down ranges at 10 % of range
Automatic
± (0.01% of reading + 0.01% of ran ge)
100 mV Range:
± (0.0 1% of reading + 0. 02 % of ra ng e)
All other ranges:
± (0 .01% of readin g+ 0.01% of range)
100 mV Range:
Fi l ter Out : ± (0 .001% of reading
+ 0.0005 % of range)/°C
Filter A or B: ± (0.001% of reading
+ 0. 0015% of range)/°C
All ot her ranges:
± (0.001% of reading+ 0. 0005 % of range)/0c
950 mic ro seconds
Vari able from 1 to 25 per se cond with
front panel contro l
Front panel pushbutton
0 to 1000 per second
Without range change:
Filter out : 1 msec to within 1 count of final
reading when triggered coincident wi th step
input voltage.
Filter A : 200 msec to within 1 co unt of final
reading
Filter B: 1 second to within 1 co unt of final
reading
Fi lter out: 4 msec per range change
Fi lter A : 200 msec per range change
Filter B: 1 second per range change
1
1

Model 3484A
Tabl e 1·1. Specifications (C ont' d).
DC VO L TS (Cont' di
Input Characteristics
Inpu t Resistance
Ef fective Common Mode Rejection
(Ratio of peak common - mode voltage to
resu
lt ant error in readi ng with 1 ki l ohm
unbalance in either lead)
DC
AC
Norma l Mode Rejection
(Ratio of peak normal - mode signal to
resultant error in reading)
Filter Selection
Zero Offset
Voltage Stability (at constant
temperature)
Voltage
Temperature Coefficient
(0°c to ss
0
c1
Cu rr ent 12s
0c ± s0
c1
Cur r ent Temper atu re Coefficient
10°c to ss
0
ci
Noise
Maximum Input Vo ltage
Between
HIGH and LOW terminals
Between
LOW and GUARD te rminals
Between
GUARD and Chassis
100 mV, 1000 mV 8nd 10 V ranges:
Greater
than 101 ohms
100 V, 1 000 V ranges: 10 megohms± 0.1%
Greater th an 80 dB
50 to 60 Hz
Fi l ter out: Greater than 80 dB
Filter A : Greater than 11 0 dB
Filter B: Greater than 1 60 dB
Filter ou t: 0 dB
Filter A : Greater than 30 dB at 50 Hz
and above
Fi l ter B: Greater th an 80 dB at 50 Hz
and above
Manual or Remote
Less than 10 microvo lt s per week
Less
than ± 1 microvolt per 0c
Less than 10 pA
L ess than 1 pA per
0c
L ess than 20 microvolts p ea k-to-peak
(unfiltered). Peak- to -peak noise is
l
ess than 20 microvo lts 95% of the
time since the noise amplitude
approx im ates a Gaussian distribution
where the standard deviation (rms value)
equals 5
microvolts.
± 1 200 V peak
± 200 V peak
±
500 V peak
Section I
1 -3

Section I Model 3484A
Ta bl e 1·1. Specificatio n s. (Co nt ' d)
14
O HM S (OP TION 0 42 )
Fu ll Scale Ran ges
50% Overrange capability on all ranges
Range Sel
ection
Automatic Rangi ng
M eas ur eme nt Ac cur acy
24 hours
(23°C ± 1°c. l ess than 50%
re l ative humidity)
90 days 12s0c ± s0 c, l ess than 95%
relative humidity)
M eas ur ing Speed
Reading Period
Reading Rate (Without range change)
Au tomatic
Manual Trigger
External Trigger
Response Time (Fu ll scale step input, without
range change)
Autorange Time
Inpu t Characte ri st i cs
Vo ltage across unknown resistance
Maximum current through unknown resistance
100 ohms, 1000 ohms, 10 ki l ohms, 100 kilohms,
1000 ki l ohms 10 megohms
Manual, Automat i c, or Remote
Upranges at 140% of range
Down ranges at 10% of range
1000 ohm thru 1000 kilohm ranges: ± (0.01% of reading
+ 0.01% of range)
100 ohm range: ±(0,.02% of r eading+ 0.05% of range)
10 megohm range: ±(0. 1% of readi ng + 0.0 1% of range)
1000 ohm thr u 1000 kil ohm ranges: ±(0.02% of readi ng
+ 0.01% of range)
100 ohm range: ±(0.02% of reading+ 0.05% of range)
10 megohm range: ±(0. 1% of reading + 0.01% of range)
950 microseconds
Va riable from 1 to 25 per second with front panel co n tro l
Front panel push butto n
0 to 1000 per second
100 oh m thru 100 k il ohm ranges (F ilt er out ): 1 msec to
with in 1 coun t of fi nal reading
1000 k il ohm range (Filter A) : 200 msec to w it hin 1 count
of final reading
10 megohm ran ge (F il te r A) : 2 seconds to wit h in 1 count
of fina l reading
Note : Due to noise generated in the unknown resistance,
filter i ng may be requ ired for quiet readings wi th i np uts
greater th an 1 00 ki lohms. Response times fo r in puts bel ow
fu ll sca le, with f il te ri ng, are proportionately less than those
shown.
Fi l ter out : 4 msec per range change
Fi l ter A : 200 msec per range change
Fi l ter B: 1 second per range change
1 V at full sca le on a ll ranges
10 mA on 100 ohm range
·r
-

Model 3484A
AC VOLTS
(OPTION 043)
Full Scale Voltage Ranges
50% Overrange capabi lity on all
ranges;
max i mum inpu t 1 500 V peak
Range Sel
ect i on
Automat ic Ranging
Response
Select ion of AC or DC Coupling
Accuracy
( 10"!6 to 150% of range; less than
108 Volt -Hertz)
24 Hours (23°C ± 1°c, l ess than
50% relative humidity
90 days (25°c ± 5°C. less
than 95% relative humidity)
Measuring Speed
Reading Period
Reading Rate
(without range change)
Automat ic
Manual Trigger
External Trigger
Response
Time (Full scale step input,
without range change)
Autorange Time
Input Characteristics
Input Resistance
Crest Factor
Maximum I nput Voltage
Table 1- 1. Specificatio ns. (Cont'd)
AC COUPLED
VAC (AC)
1 00 mV, 1000 mV, 10 V, 100 V, 1000 V
Manual or Remote
Upranges at 140% of range
Downranges
at 10% of range
Responds
to true rms value of ac input
signal. (Internally ac coup led)
Manual
or Remote
20 Hz to 1 MHz: ±(0.05% of reading
+ 0.02%
of range)
20 Hz to 1 MHz: ±:(0.05% of reading
+ 0.05%
of range)
950 microseconds
Variable from 1 to 25 per second
with front panel con tr ol
Front panel pushbutton
0 to 1000 per second
1 second
to w ithin 5 counts of final
reading
1 second
per range change
2 megohms ± 1%
7: 1 at full sca le
70: 1 at 10% of full scale
1 500 V peak ac
10 V dc (100 mV rang e)
100 Vdc (all othe r ranges)
1500 V maximum ac +de (peak)
Section I
DC COUPLED
VAC (DC)
100 mV, 1000 mV, 10 V, 100 V, 1000 V
Manual or Rem ote
Upranges at 140%of range
Downranges
at 10% of range
Responds
to tr ue rms value of ac and de
input signal.
Reading = V!DC)
2 +
(ACrms)
2
With externa l 10 microfarad coupl ing
capacitor, responds to ac component
on ly, fo r measurements down to 1 Hz.
Manual or Remote
DC: ± 0.1% of range
1 Hz
to 10 Hz: ± 1% of reading
10 Hz to 20 Hz: ±(0. 1% of reading
+ 0.05% of range)
20 Hz to 1 MHz : ±(0.05% of reading
+ 0.02% of range)
DC: ± 0.5% of range
1 Hz
to 10 Hz : ± 1% of reading
10 Hz to 20 Hz: ± (0 .1% of reading
+ 0.
05 % of range)
20 Hz to 1 MH z: ± (0.05 % of reading
+ 0.05%
of range)
950 microseconds
Variable from 1 to 25 per second with
front panel cont rol
Fr ont panel pushbutton
0 to 1000 per second
15 seconds to within 5 cou nt s of final
reading
3 seconds per range change
2 megohms ± 1%
7:1
at fu ll sca le
70 :1 at 10% of full scale
1
500 V peak ac
1 500 Vd c
1 500 V maximum ac +de (p ea k)
1-5

Section I
Ratio (348 0A /B Option 0021
Display is proportional to the ratio of the input de voltage, ac
voltage, or resistance to the external + 10 Vdc or + 1 00 Vdc
reference voltage appl ie d to rear panel Rat io termina ls.
Ratio accur acy
(+ 10 Vor + 100 V) ± 5% reference inp ut : Same as accuracy
s
pecifications for basic fu nction .
(+ 10 V
or + 100 VI + 5% to + 35 % or(+ 10 V or + 100 VI
- 5% to - 13% Reference input: Add ±0. 02 % of reading
to bas ic accuracy speci fi cations.
Ratio (Reference) In put Cha ra cte ri stics
1-6
In put Voltage : + 10 V or + 100 V referenced to circuit
com m on and Low s id e of unkn o wn input .
In put Resistance:
10 V Ref Range • 1 00 kil o hm s ± 1.5%
1 00 V Ref Range = 100 ki lo hm s ± 0.5 %
Ratio Measurement Se l ect ion : Manual or Remote
Rat
io Range Selection: Manual
General Sp
ecificat ion s
Operating Temperature : o0c to 55°C
St orage Temperature : - 40°c to + 75°c
Options a nd Accessories Available
Option 041, Isolated Remote Control
(Requ ir es 3480A/B Option 0041
Option 042, Ohms Conver t er
Opt i on 043, Tr ue rms AC Co nv erte r
Other Accessories Avai l ab le
Plug- in Extender Cable (for servicing
p lu g- in unit s)
Re
mote Program Cable (fo r all plug ·
in unit s)
Model 3484A
-
Model 11151A
Model 11 152A
Mod el 111 53 A
Model 1114 8A
Model 1114 9A

Model 348 4A
Sect io n Il
SECTION II
INSTALLATION
2-1. INTRODUCTION .
This section co ntains in formati on and instr uctions nec-
essary for installing the Model 348 4A M ul t ifun cti on Un it in
·the M ode l 348 0A /B Digital Vol tm eter. In addition, in-
st ru ct ions are gi ven for in st alling t he available options in
th e 348 4A . This section also includes ini ti al in spect io n
procedures a
nd in struct io ns for repackaging for s hi pm ent.
2- 2. INITIAL INSPECTION .
This ins trum ent w as ca re fu ll y inspected both mechanic al ly
and elec tr ically before shi pm e nt. It should be free from
mars or scratches and
in perfect electrical order up on
rece ip t. To con firm this, th e ins trum e nt should be in-
spected for physical damage in tran sit, and th e elec tr ic al
performance sho uld be tested using th e procedu re ou tlined
in
Pa ragraph S-3. If th ere is damage or deficiency, see the
warranty in s id e the fro nt co ver of this ma nual.
2- 3. INSTALLATION.
In st ru ctio ns for installing the Model 348 4A in th e 348 0A /B
Di gi tal Vo ltm eter are g iv en in Figure 2-1. In stall at ion
in stru ct ions for the Model 3480A/B are given in the
348
0A /B Operating a nd Se rvice Manual.
2-4. INSTALLATION OF ISOLATED REMOTE
OPTION 041 .
Th e followi ng proce dur e giv es in s tru cti ons for installi ng th e
Model
111 SIA Isolated Remote Assembly ( Opt ion 0 41) in
the 348 4A. If it is desired to operate remotely a 348 4A
having Isolated Remote, in a 348 0A /B t hat does n ot ha ye
Isol
ated BC D Opti on 004, r emo ve th e Isolated Remote
Assembly by reversing the
in stallation proce du re.
a. Visually ch
eck the assembly to make sure tha t th e
mo lded co ils o ff set from on e printed circu it b oa rd
ar e adjacent to and aligned wi th th e co il s on th e
o
th er bo ard. See Figure 2-2.
b. Remove
348 4A top and bo tt om guard covers.
MAN Y COMPONENT S AND ARE AS
W ITHI N THE 3 484A S HOULD NOT BE
TOUCHED . DIRT OR FINGERPRI NTS
CA N CAU SE CONTAMI NA TI ON
WHICH WILL DEGRADE THE OPER -
A
TION OF THE IN S TRU M ENT . WEA R
CLEAN RUBBER OR COTTON
GLOVES WHEN WORKING WITHIN
THE I NS TRU M ENT .
c. Remove th e sm a ll printed circuit board, having
cable a
tta ched, from printed circuit co nn ect or JS
on the top side
of the master board, near th e rear
of
th e in st rum en t.
d. Ho ld th e Isolated Rem ote Assembly as near as
possible to the position it will occu py in th e
348
4A a nd in sert th e small printed circuit board
into printed circuit co nn ec tor J4. See Fig ur e 2 -2 .
e. Insert
th e o th er end of th e Isolated Remote
Asse
mb ly in to con nector JS on the master board.
f. If th e 3 484A has Opti on 04 3 tru e rm s ac converter
installed, remove hold down screws and tilt the ac
co nv e rt er assembly so th at the master bo ard is
access
ibl e.
g. Secure th e Isolated Remote Assembly by in st aJU ng
a screw th ro ugh the master board int o the spacer
on
th e Re mot e Assembly. This sc rew should be a
6-32 x 1/4 pan hea d p oz idriv machine sc rew with
loc
kw as her, -hp· Part No. 236 0-0113.
h. Replace ac c onv ert er assembly.
i. Replace top and bo
tt om gua rd covers.
2- 5. INSTALLATION OF OHMS CONVERTER OPTION
042 .
a. Remove 348 4A top gua rd cover.
W EAR CLE AN RUBBER OR COTTON
GLOVES WHE N W ORKING WITHIN
THE 3 484 A. DIRT OR FINGERPRINT S
ON THE S WITCHE S OR PRINTED CIR ·
CUIT BOARD S WILL DEGRADE THE
PERFORMANCE OF THE INSTRU -
MENT . BE CARE F UL NOT TO APPLY
ANY PRE SS URE TO REED RELAYS.
b. Insert Ohms C on verter pr in ted circuit board in to
connector J6 and secure at oppos it e e nd with tw o
sc rews p rov ided. (6 - 32 x S/ 16 pan head p oz idriv
with ex
te rnal t oo th J ock washer, -hp- Part N o.
236 0-0ll S)
2-1

Section I.I
With latch in fully open position , insert drawer into
3480A /B
PRE SSTO RELEASE
Prm down on top surface of latch to release .
3481A -C - 30272
INSTALLATION
REMOVAL
Model 3484A
Sl ide drawlf in until latch is about two · thirch closed .
Press front surftce of latch unt il draww is fully
insert ed and latch snaps into place .
Swing latch downward end slide drewer out of
3480A / B
Figu re 2-1. Plu g -in Drawer Insta ll ation a nd Removal.
2-2
-----------
-
-

L Model 3484A
J4
Section II
SMALL PRINTED
Cl RCUIT BOARD
WITH CABLE
Figure 2-2. Isolat ed Remote Option In stallation.
c. Route input lead from Oluns Converter under
outer row of right-angle pins of connector J2, and
connect
to Att enuator Assembly Al at point
indicated
in Figure 7-3, Al Component Location
drawing.
d. Turn RANGE switch fully clockwise
to 100 mV
range. Remove knob by loosening the two set
screws.
e. Remove RANGE switch mounting
nut and care-
fully slide the switch as far as possible toward the
rear of the instrument.
f. Rotate the counterclockwise limit stop one
position counterclockwise
as indicated in Figure
2-3.
g. Replace switch carefully so that stop stays in
position. Replace mounting nut.
h. Install new RANGE knob supplied. Orient knob so
that 100 n range is opposite marker on fro nt
panel andsecure with two set screws.
i. Four wires from RANGE switch are connected to
pins labeled A, B, C, 0 near front center of
bottom side of printed circuit board. Mov e all four
wires
to the set of pins farthest from front edge of
board. Make certain that wires are kept in the
same order.
COUNTERCLOCKWISE
STOP POSITION
Without
Ohms
j. Set FUNCTION switch to VOC and remove knob.
k. Remove FUNCTION switch mounting
nut and
carefully slide
the switch as far as possible toward
the rear of the instrument.
l. Rotate clockwise limit stop one position clockwise
as shown in Figure 2-3. Make certain that the
counterclockwise
stop is in the correct position. If
the AC Converter option is also being added, this
stop should
be rotated two positions counter-
clockwise.
m. Replace switch carefully so that stops stay in
position. Replace mounting nut.
n. Two FUNCTION knobs are supplied with Ohms
Converter Option, Model l l l 52A. -hp- Part No.
5060-5953 should be used if instrument does not
have ac converter, and Pa
rt No. 5060-5954 if
instrument does have ac, or if it is also being
installed. Select and install correct knob, orienting
so that voe is oppos it e marker on front panel.
Secure knob with tw o set screws.
o. Replace top guard cover.
p. Perform Ohmmeter Accuracy Check given in
Paragraph 5-11.
FUNCTION SW I TC H
With
Ohms -- -;>..-~
®
~
W ith Ohms?<=--'< With AC
COUNTER CLOCK WI SE
.__._ .... /
RANGE SWIT CH
With out Ohms Without AC
CLOCK WI SE STOP
POSITION
COUNTERCLOCKWISE
STOP POSITION
Figure 2-3. Location of Switch Limit Stops.
'4 8 4A - ll - 30 38 i
2-3

Section II
2-6. REPACKAGING FOR S HIPMENT .
2-7. The following paragraphs contain a gene ral guide for
repackagi ng t he instrument for shipment. Refer to Para-
graph 2-8 if the orig in al container is to be used; 2 -9 if it is
not. If you h ave any ques ti ons, contact your nearest -hp·
Sa l es and Service Offi ce. (See Appendix B for office
locations.)
2-4
NOTE
If the in strument is to be s hj p pe d to
Hewlett-Packa rd for se rv ice or repair,
attach a tag to the in strument identifying
the owner and indicating the se rvi ce or
repa ir to be accomp li shed. I nc lu de the
model number and full serial numb er of
the instrument. In any co rres pondence,
identify the instrument by model number
and fu ll se r ial numbe r.
Mod el 3484A
2-8. Place instrument in o rig i nal container with appro-
priate packing mate rial and seal well with strong tape or
metal bands. Jforiginal cont ai ne r is not avai lable, o ne can
be purchased from your nearest -h p· Sales and Ser vic e
Office.
2-9. If original container is not to be used, proceed as
follows:
a. Wrap instrument in heavy paper or plastic before
pla cing in an inner container.
b. Place packing material around all sides of in stru-
ment and protect panel face with cardboard strips.
c. Place instrument and inner container in a heavy
carton or wooden box and seal with strong tape or
metal bands.
d. Mark shi p pin g container "DELI CATE I NST R U-
MENT ," "FR AG ILE," etc.

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Section III
lrl.loUIO t.0 Ml
... T·--
----
----
• 10
1.
Power switch.
2.
Function sw it ch.
3. Sample I nd icator. Flashes once for each sample period.
4. Sample Rate Contro l. Variessample rate from 1/second
to 25/second, or stops sampling when placed in HOLD
position.
5. Range sw itch .
6. Manual T ri gger Pushbutton . Instrument samples once
each
time pushbutton is pr essed and released.
7. Front Panel Zero. Adjust disp lay to zero with Input
sho rted .
8. Fi l ter switch .
9.
Front I np ut terminals.
Model 3484A
,....., ~I N~
HD/ UOV 1 ~ •a •II""" .OVll MU ,
@
~ I I
... r;~·1J. lt'@
@@
@
10 .
Terminal sw it ch. Se l ec ts fr ont or rear inp ut te rm in al s.
11. Rear In put term in al s.
12 . R emote connector. Allows remote contro l of Range,
Samp ling , Fi lt er . or Ratio mode (3480A/B Optio n 002).
1 3. 'Ratio mode switch. Permits manual or remoteselection
of Rat io mode (3480A/B Option 002).
14 . Ratio Range switch. Selects 10 V or 100 V reference
input range (3480A/B Option 002).
15. Ratio Reference I nput termina l s.
16 .
17.
18 .
Power I
nput connector .
11 5/23 0 switch. Sets 3 480 A/B to correspond to l ine
vo lt age to be used.
BCD Outpu t connector. Pr ov ides BCD ou t put, 1-2-4-8,
" 1" state positive (
3480A/B Option 003 or 00 4).
Figure 3-1. Front and Rear Panel.
3-0
-
-

-
-.
Model 3484A
Section III
SECTION Ill
OPERATING INSTRUCTIONS
3-1. INTRODUCTION.
The information contained in this section applies to
operation of the Model 3484A Multifunction Unit in either
the Model
3480A or 34808 Digital Voltmeter. The follow-
ing topics are presented:
Front
and Rear Panel Description
Function Selection
Range Selection
Sample Control
Remote Programming
Guard Connection
DC Voltage Measurements
Resistance Measurements
AC Voltage Measurements
Paragraph No.
3-2
3-3
3 -4
3-7
3-19
3-27
3- 32
3-38
3-46
3-2. FRONT AND REAR PANEL DES C RIPTION .
Figure 3-1 shows front and rear panel views of the Model
3484A installed in a Model 3480A , giving a brief descrip-
tion of controls and indicators. The Model 34808 controls
are the same as the
3480A except for the difference in
physical configuration of the instrument.
3-3. FUNCTION SELECTION .
Function may be selected either manually or remotely.
When the FUNCTION switch is set to REM, selection of
OHMS, VAC(AC), or VAC(DC) may be made by grounding
the appropriate pin
on Remote Connector Jl4. If no
remote selection is made, the 3484A automatically selects
the VDC function. Remote programming instructions are
given
in Paragraph 3-19, and Figure 3-3 shows the Remote
Connector 114.
3-4 . RANGE SELECTION .
Range may be sel ected manually, automatically, or
remotely. Manual or remote range selection permits up to
50 % overranging. The OVERLOAD indicator lights when
the numerical display reaches
15000. As the input is
increased above 15000 on any range, the display will
continue to increase until a reading of 15999 is reached.
However, readings above
15000 will not necessarily be
correct.
3-5. AUTOMATIC RANGING .
Automatic upranging occurs at 140 % of range (when
display reaches 14000). Downranging occurs
at 10% of
range.
3-6. REMOTE RANGE SELECTION.
When the RANGE switch is in the REM position, remote
selection
of range may be made by grounding the appro-
priate pin on Remote Connector JI4. If none of the range
program lines
is grounded, the 3484A will auto matically
select the highest range
(1000 V or 10 Mn). Remote
programming instructions are given
in Paragraph 3-19, and
Figure 3-3 shows the Remote Connector J.14.
3-7. S AMPLE CONTROL.
3-8. AUTOMATIC SAMPLING .
TI1e automatic sampling rate is variable from one sample
per se
cond to 25 samples per second by means of the front
panel SAMPLE
RATE control. The SAMPLE indicator
flashes once for each sample.
At rates above approximately
15 samples per second
the incandescent l amp does no t have
sufficient time to extinguish between samples,
and remains
on continuously.
3-9. MANUAL AND REMOTE SAMPLE CONTROL .
3-10. When the SAMPLE RATE control is set to HOL D or
the Interface Hold line is grounded, a sample period may be
initiated manually by pressing and releasing the TRIG
pushbutton. The instrument may also be triggered at rates
up to 1000 per second by an externalswitching device. Th e
trigger
input circuit is gated so that an External Trigger
signal
cannot be appli ed to the 3480A/B Sample Generator
during a sample period.
3-11. Trigger input
connection may be made through the
rear panel Remote connector, or the BCD Out put con-
nector if the 3480A/B has Option 003 or 004. Figure
3-2
is a diagram of the Trigger input connections.
3- 12 . Remot e Trigger Input.
3-13. The External Trigger input signal may be a circu it
closure between Remote Connector Jl4 pin 19 and groun d,
114 pin 25. If the 3480A/B has BCD Option 003 or 004,
the Trigger input closure may be between BCD Output
Connector Jl 3 pin 46 and ground, Jl 3 pin 50. The circu it
closure must be at least 50 microseconds in duration, and
the circuit must be open for at least SO microseconds
before a trigger
command is given. Minimum time between
trigger commands
is 1 millisecond.
3-14. A transistor switch
or pulse circuit may be used as an
external triggering device. The
input voltage level must be 0
to + 0.5 V for at least 50 microseconds to init iate a sample,
3-1

Section 1II Model
3484A
.-- ----- --- ---- -- - ---- ----.
I 3484A
I
I
MANUAL
I
J41[ )
ISOLATEO
J 5lEI
OELAY
ANO
I
,--
REMOTE
--, r- -
GENERATOR
~ ---
OELAYEO
-, l
I
OPTION 041
I I
TRI GGER
I
I I I CI
RCUIT
I
I I I
I l I
I I
EXT T RIG
I
RE M OTE
I
I I I
OE LAY I I
CONNECTO R I
I I
<;>---- .J
I I I
I 1 IN
J1'
I I
EXTER NAL
H
A~
3480A IB
EXTER NA L )
19
• -
-- -----
>---
TRIGGER
SA MPL E
TRIGGER
I
GATE
: I
GENERATOR
: OU T
I
~ ---- -- - ----------- .J
I
23
L __ _
~.::;
___ _____ ___ _J
- - ----
J12
BCO OUTPUT
CON NE CTOR
J13
BCD
EXTE RNAL
46
Co tt ed lin es indi ca te o pt i on als ign al path s.
TR I GGER
ASSEMBLY
-
/
3480A/8
34 8 4A - 8 - J0 3 66
Fig ur e 3-2. Ext ernal Trigger Connections.
and + 2.4 V or great er for at least 50 microseconds
precedin g a trigger comma nd. Tim e b et w een trigg er com-
mands must be not less than I millisecond. T ab le 3-2 gives a
summary of interface signal requirements.
3-15. REMOTE TRIGGERING RATE.
3-16 . De lay ed Ext e rnal Trigg er.
A jump er wire co nn ectio n on th e Range and Function
Assembly A3 permits the External Trigger (Encode) com -
mand to be delayed before triggering the 3 480A /B Sample
Generator to begin a measurement. Th e l ength of the delay
and, co n seq u ent ly , th e maximum triggering rate are de pen-
dent up on function and degree of filtering selected. In most
functions and ran ges, the de lay co rr espo nd s to the response
time of th e instrum ent, res ultin g in a correct measurement
when an External Trigger co mm a nd is applied coi n cident
with a change in input signal. Table 3-1 shows delay and
r espo n se times for the various function s. The External
Trigg er input circuit is gat ed so that after ini ti ation of a
delayed trigger co mm a nd , add i tional External Trigger com-
m ands arc blocked until after the comple ti on of the
measurement.
3- 17 . Non - delayed External Trigg er.
When the jumper on the Ran ge and Fun ction Ass embly A3
is connecte d in the OUT position, the Ex terna l Trigger
comma nd is app li ed immediately to the 3480 A/B Samp le
Generator. Conseq ue ntly , if th e time between trigger
commands is less than th e response time for the fun c tion
and filtering select ed , some erroneous measurement s may
res ult. Th e non-del ayed r emote triggering rate may be up to
1000 per second. Th e External Tr igger inpu t c ir c uit is gated
in this mode of operat ion also, preventing additional trigger
3-2
Tabl e 3-1. Delay and Res pon se Times.
FU NCTI ON
DELAY TIME RESPONSE TIME
voe
Filter OUT 4 msec 1 msec
Filter A
200 msec 2 00 msec
Filter B 1 sec 1 sec
VAC(AC) 1 sec 1 sec
VAC(DC) 3 sec 15 sec
OHMS
100 ohm range thru
100 kilohm range,
F ilt er OUT 4 msec 1 msec
1000 kil o hm range,
F il ter A
200 msec 200 m sec
10 megohm range
Fi lt er A
20 0 msec 2 sec
commands from reaching th e Sample Generat or during a
measurement period.
3- 18 . INTERFACE HO LD.
The lnterface Ho ld (Inhibi t) con n ec ti on is available at the
rear pane l R emote Connector, JI4 pin 17 (see Figure 3-3).
This line also appears at
th e BCD Output Con n ector JJ 3
pin 47,
if th e 3480 A/B has one of the BCD Opti ons. The
I nterface H old co nn ec t ion all ows th e 34 80 A/B Sample
Generator circ uit to be put in th e HOLD sta te by an
external signal when the front panel SAMPLE RAT E
con tr ol is not in th e HOLD pos iti on. Th e HOLD con dition
is produced by gro und ing the Int erface Hold co nn ec ti on or
app ly in g a voltage level of 0 to +0.5 V. An open circ uit or
a voltage level of + 2.4 V or greater allows the Samp le
G enerator to free-ru n.
-
-
-\