Tektronix DM501A User manual

COMMITTED TC EXCELLEr-JCC
INSTRUCTION MANUAL
Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon 97077 .Serial Number
,
070-2749-00 First Printing JUN 1979

WARRANTY
Tektronix v;arrants that this product is freefrom defects in materials
and workmanship. The warranty period is one (1) year from the date-
of shipment. Tektronix will, at its option, repair or replace the?
product if Tektronix determines it is defective within the, warranty
period and if it is returned, freight prepaid, to aservice, center
designated by Tektronix.
-’’ Tektronix is not obligated to furnish service under this warranty
-ra. to repair damage resulting from attempts by personnel otheri;
'rthan Tektronix representatives to install, repair, or service the
nrOfHt \r\- ::T;

OF CONTENTS
Lisl of Tables iv
List of Illustrations v
Safety Summary v
SECTION 1SPECIFICATION
English Version
Introduction i
Accessories I
Performance Conditions i
Electrical Characteristics I
Rear Interface Inputs I
Miscellaneous I
Environmental i
TM 500 Systems Environmental Specification -I
Physical Characteristics I
French Version
SECTION 2OPERATING INSTRUCTIONS
English Version
Installation and Removal instructions 2-
Controls and Connectors Il-
General Operating Information 2
Input Connections 2-
Dc Voltage Measurements 2
cCurrent Measurements 2
Ac Voltage and dO Measurements 2
Ac Current Measurements 2-
Resistance Measurements 2
Temperature Measurements .2
Repackaging Information 2-
French Version
German Version
Japanese Version

DM 501A
TABLE OF CONTENTS (cent)
THE rOLLOWING SERVICING INSTRUCTIONS ARE FOR USE BY QUALIFIED PER-
SONNEL ONLY. TO AVOID PERSONAL INJURY, DO NOT PERFORM ANY SERVICING
OTHER THAN THAT CONTAINED IN OPERATING INSTRUCTIONS UNLESS YOU ARE
QUALIFIED TO DO SO.
SECTIONS THEORY OF OPERATION Page
Introduction 3-1
Voltage Input Circuits 3-1
dB Input Circuitry 3-2
Current Input Circuits 3-3
Ohms Converter 3-4
Ten'perature Measurement Circuitry 3-5
Ana'on-to-Digital Converter 3-5
Auto-Zero Period 3-5
Measure Interval 3-5
Override Period 3-5
Display Driver 3-7
Clock 3-7
Decimal Point Circuitry *3-7
Power Supply 3-8
SECTION 4CALIBRATION PROCEDURE
Performance Check Procedure 4-1
Introduction 4-1
Calibration Interval 4-1
Services Available 4-1
Test Equipment Required 4-1
Front Panel Input Accuracy Checks 4-2
Rear Interface Accuracy Checks 4-4
Adiustrrmmt Procedure 4-11

SECTION 6OPTIONS
SECTION 7
SECTION a
SECTION 9
Standard Instruments
Option 2Instruments
REPLACEABLE ELECTRICAL PARTS
J3IAORAWS ANDJIULSTBATIONS
Troubleshooting Flowcharts
Schematic Diagrams
Parts Location Grids and Reference Tables
REPLACEABLE MECHANICAL PARTS
Exploded View
Accessories
CHANGE INFORMATION

DM 501A
Table Page
No. Title No.
1-1 Electrical Characteristics 1-1
1
2Miscellaneor‘S 1-9
1-3 Environmental 1-10
14TM 500 Systems Environmental Specification 1-11
15 fhivsical Characteristics 1-11
2rOhminotcr Source Cnirent and Voltage 2-4
'1-: 1,ist of Test Equipment Requirements 4-1
'.-2 f'jont Panel DC Vottaye Accuracy 4-5
•13 Front Panel AC Voliago Accuracy 4-6
'! -1 Front P.inol dBni Accuracy 4-6
15Front Paiml dDV Accuracy 4-6
45Front Ihrnel Resistance Accuracy 4-7
1-7 Front Pa.nel DC Current Accuracy 4-7
1-3 Front Panel AC Current Accuracy 4-8
407emperature Limits 4-8
4-10 Rear Interface DC Vcl'age Accuracy 4-8
4-11 Roar Interface AC Vollage Accuracy 4-9
112 Rear Interface Resistance Accuracy 4-9
I- 13 Fiear Interface dBm Accuracy 4-10
411 Fiear Interface dBV Accuracy 4-10
4- 15 DC Voltage Range Adjustments 4-13
tIfi AC Voltage Range Arljustments 4-13
5-
1Relalive Susceplibility to Static Discfiarge Damage 5-3
Cornponc'nt Refurcncc Ctinrts
!' 1Input Signal Conditioning
S2A/D Converter and Display Drivers
3
3PV7R Supply, Display, and Temp Circuitry

CONTENTS (cont)
Fig. Fage
No. Description No
DM 501A Digital Multimeter x
2-1 Installation and Removal 2-1
2-
2Controls and Connectors 2-3
3-
1Dc volts switching 3-1
3-2 Ac volts switching 32
3-3 dB switching v2
3-4 Dc current switching 3-3
3-5 Ac current switchiiig 3-3
3-6 Simplified otirns converter diagram 3-4
3-7 Measure interval timing 3G
3-8 Algorithm waveforms at end of measure interval .'16
3-9 Modulo 16 dual duty cycle counter waveforms 3-7
3-10 LD121 data output waveforms 33
8-1 DM 501A BLOCK DIAGRAM
8-2 ANALOG-TO-DIGITAL BLOCK DIAGRAM
8-3 ADJUSTMENT LOCATIONS
TROUBLESHOOTING FLOWCHARTS
8-4 Power Supply
8-5 Dc Volts
8-6 Dc Currents
8-7 Ohms
8-8 Ac Volts
8-9 Ac Current
8-10 Decibels (dB)
8-11 Temperature
DM 501A Probe Resistance Vs Temperature
8-12 REAR INTERFACE CONNECTOR
8-13 Switch Assignments
8-14 PARTS LOCATION GRID MAIN BOARD
8-15 PARTS LOCATION GRID ATTENUATOR BOARD
8-16 PARTS LOCATION GRID DISPLAY BOARD
8-17 PARTS LOCATION GRID SWITCH BOARD

OPERATORS SAFETY SUMMARY
The general safety information in this part of the summary is for both operating and serviciiig
personnel. Specific warnings and cautions will be found throughout the manual where they
apply, but may not appear in this summary.
TERMS
In This Manual
CAUTION statements identify conditions or practices that C'^uld result ir, da.mage to :hc
equipment or other property.
WARNING statements identify conditions or practices that could result in [icrsonal injury or
loss of life.
As Marked on Equipment
CAUTION indicates apersonal injury hazard not immediately accessible as orr,' inar!';' ti:e
marking, or ahazard to property including the equipment itself,
DANGER indicates apersonal injury hazard immediately accessible as one roads tiio mof idnq
SYMBOLS
In This Manual
This symbol indicates where applicable cautiona: •or other in'otma lion
found.
ho
As Marked on Equipment
^DANGER —Eligh voltage.
Protective ground (earth) terminal.
ATTENTION —refer to manual.
Power Source
This product is intended to operate from apower source that will not apply more th..ii EoG vol!;.
rms between the supply conductors or between either supply conductor and ground. A
protective ground connection by way of the grounding condi.'cior in the pov-'or r.ord is
essential for safe operation.

DM 501A
Grounding the Product
7'his product is grounded through the grounding conductor of hie power cord. To avoid
eleu'trical shock, plug the power cord into aproperly wired receptacle before connecting to the
profiuct input or output terminals, Aprotective ground connection by way of the grounding
conductor in ttie power cord is essential for safe operation.
Danger Arising From Loss of Ground
IJp'on loss of the protective-ground connection, all accessible conductive parts (including
knobs and controls that rrmy appear to be insulating) can reri'ler an electric shock.
Use the Proper Power Cord
Use only the power cord and connector specified for your product.
IIse only apower cord Hint is in good condition.
f-or t'etailed information on power cords and connectors, see ((^age/fig. ref.),
ro'er cord and connector changes to qualified service personnel.
Use the Proper Fuse
To avoid fire hazard, use only the fuse specified in the parts list f(jr yoLir product, and whicti is
i'.lontirial in type, voltage '"ating, and current rating.
Refer fuse replacement to qualified service personnel.
Do Not Operate in Explosive Atmospheres
To avoid explosion, do not operate this product in an atmosptiere of explosive gases unless it
lias been specifically certified for such operation.
Do Not Remove Covers or Panels
To avoid personal injury, do not remove the product covers or panels. Do not operate the
product without the covers and panels properly installed.
Co Not Operate Without Covers (for TM 500 plug-ins only)
To avoid personal injury, do not operate this product without covers or panels installed. Do not
apply power to the plug-in via aplug-in extender.

SERVICING SAFETY SUMMARY
FOR QUALIFIED SERVICE PERSONNEL ONLY
Refer also to the preceding Operators Safety Summary.
Do Not Service Alone
Do not perform internal service or adjustment of this product unless another person ca,: ibie of
rendering first aid and resuscitation is present.
Use Care When Servicing With Power On
Dangerous voltages exist at several points in this product. To avoid personal injiay, do not
touch exposed connections and components while power is on.
Disconnect power before removing protective panels, soldering, or replacing ccmp'. ;,onlo.
Power Source
This product is intended to operate from apower source that will not apply more tiirn 2ro volts
rms between the supply conductors or between either supply conductor and ground. A
protective ground connection by way of the grounding conductor in the power cord is
essential for safe operation.

SPECIFICATION
Introduction
The DM 501A Digital Multimeter measures dc voltage
and current, ac voltage and current, dBm, dBV, resistance,
and temperature. The ac functions are ac coupled only,
true rms responding. All the functions and ranges are front
panel push button selected, including the rear interface
connector input.
Readout in dBm or dBV is selected by an internal
jumper. The unit is shipped with the internal jumper in the
dBm position.
The readout is a0.4" high, 41/2 digit display using
seven segment LED. The decimal point is automatically
positioned depending on the selected operating range of
the instrument. Polarity indication is automatic.
Accessories
Standard accessories include this instruction manual, a
set of test leads and the TEKTRONIX P6601 temperature
probe with its instruction manual.
The P6601 temperature probe r.uci tei.iperatiire
measurement capabilities are deleted foi Option 2in-
struments.
Performance Conditions
The electrical characteristics a;e vr.iid o.niy if the
DM 501A has been calibrnted a' nr, nmbi ;;: loniperr.ti ,c
between I21°C and f25''C aiul is Oj'cr ding a! an ambient
temperature between O' Cand iG j"C, c'herwire
noted.
Items listed i;-. the Pci forruance Reqii.i 'mcuis
of the Electrical Ciraractorislics a, o.Tri'ioL, lycc i, lelmg
the Performance Check in the COiin atio: ipor :,j,; 11; lliis
manual. These items are eitlTcr nxplanatoiy ncies or
performance ct'.aracterisLc.s for v.rhich :.o limits are
specified.
Table 1-1
ELECTRICAL CHARACTERISTICS (Fror, Panel)
Characteristics Performance Requirements Supplement: Iiidoimalion
DC VOLTMETER
Accuracy for 200 mV, 2V, 20 V
200 Vand 1000 Vranges
tIS^C to +28°C
200 mV range ;* (0.05% of reading 10.015% of full
scale)
2Vto 200 Vranges ±(0.05% of reading 10.01% of full
scale)
1000 Vrange ±(0.05% of reading t0.02% of full
scale)
1
0"C to f18°C, -1 28°C to 150°C 1
200 mV to 200 Vrange ±(0.1% of reading t0.025% of full
scale)
1000 Vrange ;f (0.1% of reading L0.05% of full
scale)
x@1-1

Specification—DM 501A
Table 1-1 fcont)
Characteristics Performance Requirements Supplemental Information
DC VOLTMETER (coni)
Convnor: '/'ode Rejection Ratio 100 dB at dc.
80 dB at 50 and 60 Hz.
With a1kn unbalance.
rJormal Mode Rejection Ratio 60 dB at 50 or 60 Hz 10.2 Hz.
Maxi'Ti'irn F^esolution 10 /iV.
Stej) RoE[ionse Time 1second.
Input Resistance 10 MO ±0.5%.
Maximum input Voltage
VO’lTS/0to LOW 1000 Vpeak.
V(TLTR/n to graund 1000 Vpeak.
LOW to groupe'
!npu; Oonnoctors
tOOO Vpeak.
Front panel (EXT) or rear interface
(!NT)
AC VOLTMETER (TRUE RMS)
Accuracy for 200 mV, 2V, 20 V
200 Vand 500 Vranges
fTS"C to f28° C
Input signal must be between 5% and
100% of full scale. The 500 Vrange
requires adynamic input signal
between 500 Vand 100 Vrms,
200 mV to 200 Vranges
-10 it/, to 10 kHz !(0.6% of reading 10.05% of full
'"ale)
20 '2' to 40 Hz and
10 kHz to 20 kHz
1(1.0% of reading 10.05% of full
scale)
500 Vrange
:o Hz to 10 kHz
20 1tz to 40 }Iz and
10 kHz to 20 k! Iz
1(0.6% of reading 10.2% of full
scale)
L(1.0% of reading 10.2% of full
scale)
C°C to i18^C, i28°C to I50°C
200 mV to 200 Vranges
40 Hz to 10 kHz L(0.8% of reading L0.075% of full
scale)
29 1!z to 40 fIz and
10 kHz to 20 kHz
-t(1.3% of reading f0.075% of full
scale)
500 Vrange
40 1Iz to 10 kklz ±(0.8% of reading 10.3% of full
scale)
20 Hz to 40 Hz and
10 kHz to 20 kHz
1(1.3% of reading +0.3% of full i
scale)
@1-2

Table 1-1 (conf)
Characteristics Performance Requirements jSupplemental ln;om--.Uon
AC VOLTMETER (TRUE RMS) (cont)
Common Mode Rejection Ratio 60 dB at 50 and 60 Hz. With a1kn unoalanuc.
Maximum Resolution ^0^JV.
Response Time <2 seconds.
Input Impedance 10 Mn ±0.5% p'.ralleled by 1GC pF.
Input Connectors Front panel (EXT) or rear interface
(INT).
Maximum Input Voltage
VOLTS/n to LOW
500 Vrms or 600 Vdc not to exceed
1000 Vpeak.
VOLTS/n to ground 1000 Vpeak.
LOW to ground 1000 Vpeak.
Crest Factor 4at full scale.
DECIBELS (d3)—TRUE RMS
1
Accuracy for -40 dB, -20 dB,
0dB, I20 dB and F40 dB ranges
j
-M8"C to 128'’C i
i20 dB to -15 dB iO.5 dB 20 Hz to 20 kHz
ISdBto -20 dB .t.0.5 dB 20 Hz to 2 kHz
.11.5 dB 2kHz to 10 kHz Typic.'lly
<: .12,5 dB 10 kl iz to 20 i<H,a
0"C to HS^C, +28"C to 150‘’C
120 dB to -15 dB ti tdB 20 Hz to 20 kHz
j
-15 dB to -20 dB t1 1dB 20 Hz to 2 kHz I
i2.1 dB 2kHz to 10 kHz Typicaily <.1 3.1 dB 10 11 Iz to 20 ki
Maximum Resolution 0.1 dB,
Response Time <2 seconds.
Input Impedance 10 Mn paralleled by 100 pF.
Maximum Input Voltage
VOLTS/n to LOW 500 Vrms or 600 Vdc rr.'t to exceed
1000 Vpeak."
VOLTS/n to ground 1000 Vpeak.
LOW to ground 1000 Vpeak.
'Equivalent to 54 dBV or 56.2 dBm.
RC-y AAUG 1979 13

Specification—DM 501A
Table 1-1 (cont)
Characteristics Performance Requirements Supplemental Information
Crest Factor 4at full scale.
Ref Voltage i
cinv 1V.
dRm 07746 V(1 mW dissipated into
600 O). Selected by internal
lumper.
Input Oofiiiectors
^1
1
Front panel (EXT) or rear interface
(IMT).
L-...
OHMMETER
Accurdcy for 200 0, 2kO, 20 kQ, 1
gno 10, 2000 kO and 20 MO ranges, j
kk’C, 128‘"C
20C 0to 200 kO LO O
2kO to 2000 kO HI Q
1
.! (0.15% of reading 10.015% of full
scale)
moo ki7 LQ ’1(0.3% of reading 10.015% of full
scale)
20 MO HI 01.(0 5% of reading t0.015% of full
scale)
1
0''t; to :IS'-'C, 12S“C to I50“
C
2( 00tci 200 kO 1.0 0
2KO to 2000 kO HI 0
1
1
!
k(0.3% of reading 10.025% of full
scale)
2000 KO I..0 0
20 MQ HI n
!^(1.2% of reading t0.025% of full
j
scale)
Mnxinuan Input Volts Any Range
1
250 Vpeak.
Measuring Current and Full
i
1
1Source VMax at
Scale Volts 1Range Current Full Scale
11: 0200 01.0 mA 0.2 V
2kO 1.0 mA 2.0 V
i20 kO 0. 1mA 2.0 V
1
200 kO 10.0 /jA 2 0 V
2000 kn 1.0 2.0 V
20 MO 0.1 pA 2.0 V
1.0 o11200 Q1.0 mA 0.2 V
!2kO 0. 1mA 0.2 V
20 kO 10.0 /jA 02V
200 kO 1.0 fjA 0.2 V
1
1
1
‘
12000 kO 0.1 /jA 0.2 V
20 MO 0.1 /rA 20V
1-4 REV AAIJi) 1979

.A
Table 1-1 (coni)
Characteristics Performance Requirements Suppiemer lal infomaTon
Maximum Resolution 10 mO, i
Response Time <2 seconds, 200 Qto 2000 kO. ,
<10 seconds, 20 MO scale. |
Maximum Open Circuit Voltage <6 V.
Input Connectors Front panel (EXL) or reai interlace
(INT).
DC AMMETER
Accuracy for 200 pA, 2 mA, 20 mA,
200 mA and 2000 mA ranges.
TT8°C to +28” C1(0.2% of reading -1 0.015% of full
scale)
0”C to +18°C, T28°C to I50”C .1(0.3% of reading I- 0.025% of full
scale)
Response Time <1 second.
Input Resistance Range
Appioxiiiiate
Rcsstance
200 1.0 kO
2nA,00.0 0
20 mA 10.2 n
200 mA 1.2 0
2000 m.A 0.4 v)
Maximum Input Current 2Aar.y range.
Maximum Open Circuit Input
Voltage (mA to LOW) 250 Vpeak.
Maximum Floating Voltage
mA to ground |1000 Vpeak.
LOW to ground ]1000 V;eak.

Specification—DM 501
A
Table 1-1 (cont)
Characteristics Performance Requirements Supplemental Information
AC AMMETER (coni)
Maximum Input Current
1
2Aany range.
Maximum Open Circuit Input
Voltage (mA to LOW)
!250 Vpeak.
1
Maxii'i'irn Floating Voltage
fpA to grounc! U>00 Vpeak.
LOW '0 ground lUOO Vpeak
ln[)u! Connectors Front panel only.
Maxirnum Resolution 10 nA
TEMPERATURE
Accurticy tor ttio G2"'C to
i240‘'C range.
•Idc Cto 128 'C ambient
Probe calibrated to
instrument
:i.2‘'C from 62"C to 1ISC^C.
F0°CtO -6°Cfrom l-150°C to t240“C
Any probe ;.4°C from -62°C to t150“C.
F2"Cto 8°Cfrom 1150°Cto (240'^C
9‘'Cto I18°C, l28°Cto I50“C Add l.5°C to ttie above tolerance in
each direction.
I'lpnt Connoctor‘3 ^ront panel (EXT) or rear interface
(INT).

Table 1-1 (cont)
ELECTRICAL CHARACTERISTICS (Rear Interface Inputs)
Characteristics Performance Requirements Supplemental Ir.iorma'ion
Maximum Input Voltage (dc, ac,
dB, and ohms)
Pin 28B to 28A 200 Vpeak. Ec;uivnlcii! io 43 OBV
or 45.2 dBm.
Pin 28B to ground 200 Vpeak.
Pin 28A to ground 200 VpeaK.
DC VOLTMETER (REAR INTERFACE INPUTS)
Accuracy for 200 mV, 2V, 20 V,
200 Vand 1000 Vranges.
t18'“C to +28° C
200 mV range ±(0.05% of reading i- 0.015% of fuli j
scale)
2Vto 200 Vrange ±(0.05% of reading f0.01% of full
scale)
1
1000 Vrange ±(0.05% of reading F0.02% of full :
scale)
1
0°C to +18°C, +28°C to +50°C
200 mV to 200 Vrange J:(0. 1% of reading 10.025% of full
scale)
1000 Vrange ±(0.1% of reading f- 0.05% of full
scale)
REV AJAN 1980

Specification—DM 501A
Table 1-1 (coni)
Characteristics
|
Performance Requirements ;Supplemental Information
AC VOLTMETER (REAR INTERFACE INPU TS)
Accuracy >c" 200 mV, 2V, 20 V,
200 Vand 50Q Vranges.
!18°C to I28" C
200 mV to 200 Vrange
'!0 ]'z to 10 kHz
20 IIz to 40 Hz and
10 kHz to 20 kHz
,' 0;) Vrange
40 11z to 10 kHz
20 Hz to 40 tIz and
10 kHz to 20 kHz
C"C to !18°C, I28° Cto 150° C
200 rnV to 20C Vrange
40 I!z to 10 kHz
20 IIz to 40 Hz and
10 kHz to 20 kHz
200 Vrange
40 Hz to 10 kHz
20 fIz to 40 Hz and
10 kHz. to 20 kHz
i;{1.6% of reading I0.05% of fgll
scale)
L(2.0% of reading I0.05% of full
scale)
j
}.{1.6% of reading 10.2% of full
!scale)
(
-r(2.0% of reading 10.2% of full
scale)
i1(1.8% of reading I0.075% of full
scale)
1(2.3% of reading I- 0.075% of full
Iscale)
i
,1.(18% of reading l0.3% of full
j
scale)
1(2.3% of reading L0.3% of full
iscale)
Input signal must be between 5% and
100% of full scale input. The 500 V
range is limited to between 200 V
['oak and 100 Vrms.
DECIBEL.S (dB)—TRUE RMS (REAR INrERFACL INPUTS)
Aci i.'fT'cy for 40 dB, 20 dB, i
0ilB, !20 dB and i40 dD ranges
^
'13 Clo !?8°C !:
20 (IB to 15 dB }0.6 dB 20 Hz to 20 kt Iz
'0 (IB !o 20 (JB 10 6dB 20 Hz to 2 kHz
‘16dB 2kHz to 10 kHz Lypically
2.B dB 10 kHz to 20 kHz
to ;P,'C .!23 'C lo f50°
C
20 (IB to 15 dB (12 dB 20 Hz to 20 kHz
j
15 dB to 20 dfl r1 2dB 20 Hz to 2kHz
122dB 2kHz to 10 kHz
!Typically
:3.2 dB 10 kklz to 20 kHz
1RREV BJAN 1980