Tektronix,
Inc.
p.0.
Box
500
Beaverton,
Oregon
97077
COMMlTED
EXCELLENCE
INSTRUCTION
MANUAL
Serial
Number
070-2692-
00
First
Printing
MAR
1979
WARRANTY
his
Tektronix product is
1
~d
against
defect
rials
and
orkmanship, under normal
use,
for
a
period
of
one
year
rrom
date
f
initial shipment.
Tektronix
will repair
or
replace, at its
option,
bose
products determined to
be
defective within the warranty
eriod and returned, freight prepaid,
to
a
Tektronix Service Center.
here
is
no
implied warra itness
of
purpoa
art
numl
ive
mate
nty
for
f
i
for
ierl
lease
direct all
I
vice
or
replacerr
earest Tektronix
aerrlce
lvertrer
or
Field
Office;
include
the
rypr
or
Jer
of
th
requests
..--..I--
be.
lent
par'
vright
@
tents
oft
.
.
ct
and
it s serial
number.
nix, Inc.
lay
not
b
-.
ts
to
the
-I
--
his publication
rr
e
reprad
vllJ
,,, ,,,
without the
permission
of
Tektronix,
Inc.
Prod
cove
lucts
of
red
by
Tektro
U.S.
an
nix,
Inc
d
foreis
.
and
its
subsidiaries
are
In
patents
and/or
pending
patents.
TEKTRONIX
E-MOBILE,
and
@
are
registered
traaemar~s
or
r
edronix,
1
Printed
in
U.S.A.
privileges are reservt
nc.
3nd
pril
TABLE
OF
CONTENTS
Page
................................................
LIST
OF
ILLUSTRATIONS
iv
.......................................................
LISTOFTABLES
V
...........................................
OPERdTORS
SAFETY SUMMARY
~ii
............................................
SERVICING
SAFETY
SUMMARY ix
SECTION
1
SPECIFICATIOM
...........................................
Introduction 1-1
..................................
Performance Conditions 1-1
........................
Electrical Characteristics (Front Panel) 1-1
........................................
Dc
Voltmeter 1-1
........................................
Ac
Voltmeter
1-2
..........................................
Ohmmeter
1-3
........................................
Dc
Ammeter 1-3
........................................
Ac
Ammeter
1-4
......................
Electrical Characteristics
(Rear
Interface)
1-4
Dc
Voltmeter
........................................
1-4
........................................
Ac
Voltmeter 1-5
..........................................
Ohmmeter
1-6
.........................................
Miscellaneous 1-7
..............................
Environmental Characteristics
1-7
........................................
DM
505 Only 1-7
.....................................
TM
500
Systems
1-8
..................................
Physical Characteristics 1-9
SECTION
2
OPERATING INSTRUCTIONS
...................................
l nstallation l nstructions 2-1
.................................
Controls
and
Connectors
2-2
.................................
Operators Familiarization
2-2
...........................
General Operating Information
2-2
....................................
l
nput
Connections
2-4
...................................
Si ne-wave Response
2-4
...............................
Dc
Voltage Measurements 2-4
..............................
Dc
Current Measurements
2-4
.....................
Ac
Voltage
and
Current Measurements
2-4
Resistance Measurements
...............................
2-4
Packaging Information
...................................
2-5
TABLE
OF
CONTENTS
(cont)
Page
SECTION
6
OPTIONS ..............................................
61
SECTION
7
REPLACEABLE ELECTRICAL
PARTS
SECTION
8
DIAGRAMS
AND
CIRCUIT
BOARD
ILLUSTRATIONS
Simplified
Block
Diagram
Rear
Interface
Connections
ND
Block
Diagram
Adjustment
Locations
Troubleshooling
Flow
Charts
Parts
Locations
Component
Reference
Charts
Schematics
SECTION
9
REPLACEABLE
MECHANICAL
PARTS
AND
EXPLODED
VIEW
CHANGE
INFORMATION
iii
Fig.
No.
Frontis
LIST
OF
ILLUSTRATIONS
Description
....................................
DM
505
Digital Multimeter
...............................
DM
505
Installation and Removal
............................
Front
Panel
Controls and Connectors
........................
Simplified Diagram
of
the
Ohms
Converter
....................................
Auto-zero timing intervars
..................................
Measurement
interval
timing
DM
505 Simplified Block
Diagram
8-2
A/D
Converter Block
Diagram
8-3
Adjustment Locations
TROUBLESHOOTING
FLOW
CHARTS
Power
Supplies
Dc
Volts
Dc
Current
Ohms
Ac
Volts
Ac
Current
Main
Board
(A10)
Display
Board
(A1
1)
Page
No.
LIST
OF
TABLES
Title
Page
No
.
ELECTRICAL CHARACTERISTICS (Front Panel)
1-1
DcVoltmeter
................................................
1-1
.................................................
1-2
AC
Voltmeter
1-2
..................................................
1-3
Ohmmeter
1-3
ELECTRICAL
CHARACTERlSTlCS
(Rear
Interface)
1-6
DcVoltmeter
................................................
1-4
1-7
AcVoltmeter
................................................
7-5
1-8 Ohmmeter
..................................................
1-6
.................................................
1-9 Miscellaneous 1-7
ENVIRONMENTAL CHARACTERISTICS
1-10
DM
505
Only
................................................
1-7'
..............................................
1-1
1
TM500Systems
1-8
PHYSICAL CHARACTERISTICS
Physical
Characteristics
........................................
1-9
.....................................
Current
Mode
input
Resistance
2-4
...............................
Ohmmeter Source Current
and
Voltage
2-5
Ohms
Converter Source Current
and
Maximum Full-scale Voltage
............
3-2
List
of
Equipment Requirements
....................................
4-1
............................................
Dc
Voltage
Accuracy
4-3
Ac
Voltage
Accuracy
.........................
...
................
4-4
................................................
Ohms Accuracy 4-6
............................................
Dc
Current Accuracy
4-6
............................................
Ac
Current Accuracy 4-7
Dc
Voltage Accuracy for
Rear
l
nterface
...............................
4-7
...............................
Ac
Voltage
Accuracy
for
Rear l nterface 4-8
...................................
Ohms Accuracy
for
Rear
Interface
4-8
.......................
Relative Susceptibility
to
Static Discharge
Damage
5-2
Rear
Interface
Connector
Assignments
Component
Reference
Chart
@
Component
Reference
Chart
@
OPERATORS
SAFETY
SUMMARY
The general
safety
information in this
part
of
the
summary is for both operating and servicing
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 could
result
in damage
to
the
equipment
or
other
property.
WARNlNG
statements
identify conditions
or
practices
that
could
result
in
personal
injury
or
loss
of
life.
As
Marked
on
Equipment
CAUTION
indicates
a
personal
injury
hazard
not immediately accessible
as
one
reads
the
marking, or
a
hazard
to
property
including
the
equipment itself.
DANGER
indicates
a
personal
injury
hazard
immediate1
y
accessi
bleas
one
reads
the marking.
SYMBOLS
In
This
Manual
This
symbol indicates
where
applicable cautionary
or
other information
is
to be
found.
As
Marked
on
Equipment
/j
DANGER
-
High
voltage.
@
Protective
ground (earth) terminal.
ATTENTION - refer
to
manual.
vii
Power
Source
This
product is intended to operate in a power module connected
to
a
power source that will
not
apply
more than
250
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.
Grounding
the
Product
f
his product
is
grounded through
the
grounding conductor of the power module power cord.
To avoid
electrical
shock,
plug the power
cord
into a properly
wired
receptacle before
connecting to
the
product input or output terminals.
Upon
loss
of
the protective-ground
connection,
all accessible conductive
parts
(including knobs and controls
that
may
appear
to
be
insulating), can render
an
electric
shock.
Use
the
Proper
Fuse
To
avoid fire hazard, useonly the fusespecified in
the
parts list for your
product,
and
which
is
identical
in
type, voltage rating,
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
atmosphere of explosive gases unless
it
has been specifically certified for such operation.
De
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.
Do
Not
Operate
Without
Covers
To
avoid personal injury, do not
operate
this pr~duct without
covers
or panels installed.
Do
not
apply power to the plug-in
via a plug-in extender.
viii
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 capable
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 injury,
do
not
touch
exposed
connections
and
components while power
is
on.
Disconnect
power
before
removing protective
panels,
soldering,
or
replacing corn
ponents.
Power Source
This
product
is
intended to
operate
in
a
power
module
connected
to
a
power
source
that
will
not
apply
more
than
250 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.
Section
1-DM
505
SPECIFICATION
Introduction
The
DM
505
Digital M ultimeter measures
resistance,
dc
or
ac
voltage, and
dc
or
ac current.
The
AC
functions
respond
to
the average value of an
ac
current or voltage
and
the
readout displays the sinusoidal rms value. In the
resistance
mode
of
operation, the HI
n-LO
fi
pushbut-
ton selects either
of
two
full-scale
probe
tip voltages.
The
front panel
pushbuttons
select the functions and
ranges.
The
INPUT pushbutton selects front panel
con-
nector input
(
EXT)
for current, voltage
and
resistance
measurements, or
rear
interface
connector input (INT) for
voltage
and
resistance measurements.
The
readout is
a
3
1/2
digit display
using
seven-segment
LED.
The
decimal
point
is automaticaSly positioned
by
the range pushbut-
tons.
The polarlty signs for
dc
voltage and dc current
measurements are
also
displayed automatically.
A
blink-
ing display indicates overrange except
on
the
1000
Y
dc
and
500
Y
ac
ranges.
The
reading rate
IS
approximately
three readings per second.
Performance
Conditlons
The
electrical characteristics
are
valid only
if
the
DM
505
has been calibrated
at
an ambient temperature
between
+21°C
and
i-25"
C
and
is operating
at
an ambient
temperature between
O0
C
and
4-50"
C,
unless otherwise
noted.
Items listed
in
the Performance Requirements
column
of
the Electrical Characteristics are verif
led
by
completing
the Performance
Check
in
this manual. Items listed in the
Supplemental Information column
are not verified in this
manual.
They
areeither explanatory notes or
performance
characterist~cs for
which
no limits are specified.
ELECTRICAL
CHARACTERlSTlCS
Front Panel
Table
1-1
0C
VOLTMETER
Supplemental
information
Characteristics
Accuracy for the
200
mV,
2
V,
20
V,
200
V,
and
1000
V
ranges:
+I
8"
C
to
+28"
C
200
mV
to
200
V
ranges
1000
Y
range
Performance
Requirements
+(O.l%
of reading
+
0.05°h
of full
scale)
f
(0.1%
of reading
+
O.T%
of
full
scale)
O°C
to
+18"C,
+28"C
to
+50°C
200
mV
to
200
V
ranges
1006
V
range
Common
Mode
Rejection
Normal
Mode
Rejection Ratio
Maximum Resolution
Response Time
Input Resistance
it(0.2%
of
reading
+
0.1
%
of
full scale)
f
(0.2%
of reading
f
0.2%
of
full scale)
3100
dB
at
dc.
280
dB
at
50
to
60
Hz.
350
dB
at
50
and
60
Hz
k0.2
Hz.
Verified with
1
kR
unbalance at
the
LOW
terminal.
(Clock frequency:
20.48
kHz
tl%.)
1
00
pV
<0.5
second to rated accuracy.
f
0
Mfl
f
0.5%.
Table
1-1
(cont)
Table
1-2
AC
VOLTMETER
Characteristics
Maximum
lnput
Voltage
VOLTS/R
to
LOW
1-2
REV
A
OCT
1979
Performance Requirements
Supplemental
Information
1000
V
peak.
VOLTS/R to Ground
LOW
to
Ground
Supplemental Information
Charaderlstics
Accuracy
for
the
200
mV,
2
V,
20
V,
200
V
and
500
V
ranges:
+lBO
C
to
+28'
C
200
mV
to
200
V
ranges
45
Hz-10
kHz
sine
wave
25-45
Hz,
10-20
kHz
sine
wave
1000
V
peak.
1000
V
peak.
Performance
Requirements
f
(0.5%
of reading
+
0.1
%
of full scale)
f
(1%
reading
+
0.1%
of
full
scale)
500
V
range
25
Hz-10
kHz
sine wave
f
(1%
of
reading
1-
0.4%
of full scale)
0°
C
to
+18"
C,
+28"
C
to
4-50" C
200
mV
to 200
V
ranges
45
Hz-10
kHz
sine
wave
&(I%
of
reading
+
0.15%
of
full scale)
25-45
Hz,
1G20
kHz
sine
wave
f
(1.5%
of
reading
+
0.15% of
full
scale)
500
V
range
25
Hz-10
kHz
sine
wave
Common
Mode
Rejection
Ratio
Maximum Resolution
Response
Time
f
(1.5%
of reading
+0.6Oh
of
full scale)
250
dB
at
50
to
60
Hz.
Verified with
1
kR
unbalance
at
the
LOW
connector.
100
pV.
<1.5
seconds,
within
specified
accuracy
on
measurements
within
any
one
range.
Input
Impedance
Maximum
lnput Voltage
VOLTS/R
to
LOW
10
MR
+0.50J0
paraHeled
by
less
than
130
pF.
566Y
ac
rms
or600Vdc,
nottoexceed
1000
Y
peak.
VOLTS/fl
to
Ground
LOW
to
Ground
500
V
ac
rms
or
600
Vdc,
not
to
exceed
1000
V
peak.
500
V
ac
rms
or
600
Vdc,
not
to
exceed
1000
V
peak.
Maximum
Volt-Hz
Product
107
VaHz.
Table f -3
OHMMETER
f
f
8°C
to
+2a°C
200
R
range
200
R
range
pproximatel
y
f
6
V.
Table
1-4
PC
AMMETER
CharaeZerEstlcs
Accuracy
for
the
200
PA,
2
rnA,
20
mA,
200
rnA
and
2000
mA
ranges:
+lg°C
to
+2g°C
0°Cto+180C,+z80Cto+~~0C
Response
Time
Maximum
Open
Circuit
Input
Voltage
mA
to
LOW
Performance
Requirements
f
(0.3%
of
reading
+
0.05% of
full
scale)
f(O.4Y0ofreading+O.l%offullscale)
Supplemental
Information
<0.5
second.
250
V
peak.
TaMe
1-4
(cont)
Characteristics
Maximum
Floating
Voltage
mA
to
Ground
Low
to
Ground
Table
1-5
1000
V
peak.
1000
Y
peak.
Maximum Resolution
kC
AMMETER
Performance
Requirements
0.1
PA.
Accuracy
for
the
200
PA,
2
mA,
20
mA,
200
mA,
and 2000
rnA
ranges:
45
Hz
to
10 kHz
Response f ime
Maximum
Open
Circuit
Input
Voltage
Maximum
Floating Voltage
Supplemental
Information
ELECTRICAL
CHARACTERISTICS
Rear
Interface
fable
1-6
DC
VOLTMETER
Characteristics
Performance Requirements Supplemental
1nformatlon
Accuracy
for
the
200
mV,
2
V,
20
V,
200
V
and
1000 V ranges:
200
mV
to
200
V
ranges
1000
V
range
f
(Q.tYo
of
reading
+
0.05% of full scale)
f
(0.1%
of
reading + 0.1%
of
full
scale)
Table
1-6
(cont)
Supplemental
Information
200
mV
to
200
V
ranges
1000
V
range
f
(0.2%
of
reading
4-
0.1%
of
full
scale)
f
10.2%
of
reading
t
0.2%
ot
full
scale)
Maximum
Resolution
--
Response
Ti
rn
e
lnput
Resistance
<0.5
second
to
rated
accuracy.
Maximum
lnput Voltage
Pin
28B
to
Pin
28A
200
V
peak.
Pin
28B
to
Ground
200
V
peak.
Pin
28A
to
Ground
200
V
peak.
Table
1-7
AC
VOLTMETER
Performance
Requirements
Supplemental
Imformation
Charaderisttics
Accuracy
for
the
200
mV,
2
V,
20
V,
200
V
and
500
V
ranges:
200
mV
to
2
V
ranges
45
Hz-10
kHz
sine
wave
f(0.5%
of
reading
f
O.lP/o
of
full
scale)
25-45
HZ,
110-20
kHz
sine
wave
20
V
to
200
V
ranges
25
Hz-20
kHz
sine wave
f
(I0h
of
reading
+
0.1%
of
full scale)
+(lO/o
of
reading
+
0.I0/o
of full scale)
500
V
range
(max.
input:
200
V)
25
Hz-10 kHz
sine
wave
f
(1%
of
reading
-t
0.4O/o
of full
scale)
200
mV
to
2
V
ranges
45
Hz-10 kHz
sine
wave
25-45
Hz,
10-20
kHz
sine
wave
20
V
to
200
V
range
f
(1%
of
reading + 0.15%
of
full scale)
f
(1.5%
of
reading
+
0.15°h
of
full
scale)
25
Hz-20
kHz sine
wave
f
(1.5%
of
reading
+
0.1
Soh
of
full
scale)
500
Y
range
(max.
input:
200
V)
.
f
(1
-5%
of
reading + 0.6%
of
full scale)
25
Hz-10 kHz
sine
wave
Table
1-7
(cont)
Table
1-8
OHMMETER
+lB°C
to
+28OC
200
!J
range
200
fl
range
reading
$
0.15%
of
full
scale
Supplemental
Infwrnation
I00
pV
<I
.5
seconds,
within
specified
accuracy
on
measurements
within
any
one range.
200
V
peak.
200
V
peak.
200
Y
peak.
Characteristics
Maximum
Resolution
Response
Time
Maximum
l
nput
voltage
Pin
288
to
Pin
2814
Pin
288
to
Ground
Pin
28A
to
Ground
Maximum
Volt-Hz
Product
lo7
V~HZ.
Performance
Requirements
Table
1-9
MISCELLANEOUS
ENVIRONMENTAL
CHARACTERISTICS
Table
1-10
DM
505
ONLY"
Operating
Operating
i-30°C
and
+50°C
at
90%,
1-5
-O%I~
-T-28800B,
class 5 with
Operating
0.64
mrn
(0.025")
disp.,
5-55-5
H?
Test
to
MI L-t-28&00B, class
3.
(sine
wave)
75
min. total.
Non-operating
50 g (1/2
sine)
11
ms*
Test
to MIL-T-288OOB, class
3.
Operating
45O
or
4"
or
equilibrurn,"'
Test
to
M
l
t-T-28800B, class
3.
Supplemental
lnformatlon
Approximately
8
W.
Characteristics
Power
Consumption
Performance
Requlrements
Reading
Rate
Over-range
Cali
bration
Interval
Warm-up
Tirna
3
per
second.
Flashing display
(except
1000 V dc and
500
Y
ac
ranges).
fOOQ
hours
or
six
months, whichever
occurs
first.
30
minutes
(60minutesaFterstorage
in
high
humidity
environment).
Table
1-10
(cont)
'See
Table
1-11
for
system
envfronmental characterlstlcs.
Characteristics
E.M.C.
Operating
Electrical Discharge
Operating
Transportation
with
power
module.
Description
30
Hz
to
1
GHZ~
Test
to
MI
L-T-288008,
class
3.
20
kV
rna~.~
Charge applied to
each
protruding
area
of
the
product under test except the input
terminals.
Qualified under National
Safe
Transit
Association Preshipment Test Procedures,
Project
1
A-B-1
and
Project
t A-B-2.
'without
power
module.
d~ernperature:
Durlng
$ow
temperature
test
MIL-T-28800B,
paragraph
4.5.5.1.3(b)
for
dass
5,
steps
4
and
5
shall
be
per-
formed
before
step
2,
Also,
the
instrument shall not
be
operating
durhg
step
6,
paragraph
4.5.51.3(e),
class
5.
Whlle
aperating,
condensed
molsture
shall not
be
present
on
class
5
Instruments.
Drying
of
the
instrument
for
thFs
class
may
be
performed
in
a
suitable
chamber,
if
necessary.
CHumldlty: The
20
V
ac
and
200
Y
ac
ranges
shall
be
derated
to
f
25%
of
readlng
+2
counts.
Note:
All
performance
requirements
are
met
while
operating
at
w95%
relative humldlty
at
f
30°C
and
f
50°C
with
on
hour wnrmup.
Table
1-11
TM
500
SYSTEMS
I
Characteristics
Temperature
TM
501
TM
503
TM
504
TM
506
TM
515
Operating
Non-operating
Meets
same
test standards
as
plug-in.
Meets
same
test
standards
as plug-in.
Humidity
Operating Meets same Zest standards
as
plug-in.
Non-operating
Altitude
Meets
same
test standards
as
plug-in.
Operating
Meets
same
test standards as plug-in.
Non-operating
I
Meets
same test standards
as
plug-in.
PHYSICAL
CHARACTERISTICS
Table
1-12
TM
515
0.38
mm
(0.015
in)
disp.
10-55
Hz
(sine
wave)
75
min.
30
g
(1/2
sine)
11
ms,
18
shocks
CharacterlsUcs
TM
501
TM
503
TM
504
TM
506
Characteristics
Deswlption
Bench
Handling
Qperati
ng
Electrical
Discharge
Operating
Transportation
Vibration
Package
Drop
Finish
Net
Weight
Overall
Dimensions
Meets
same
test
standards
as
plug-in.
Meets
same
test
standards
as
plug-in.
Meets
same
test
standards
as
plug-in.
Meets
same
test
standards
as
plug-in.
VI
bration
Operating
Shock
Operating
Anodized aluminum panel
and
chassis.
2.2
I
bs
(exclusive
of
probes)
(1
kg).
2.m
in
(86.8
mm)
W X 11.240
in (285.3
mm) D X
4.961
in
(125.9
mm)
H.
0.26
mm
(0.01
0
in)
disp.,
j0-55
Hz
(sine
wave)
75
min.
total
20
g
(1/2
sine)
11
ms
18
shocks
Section
2-DM
505
OPERATING
INSTRUCTIONS
Installation Instructions
The
DM
505
is calibrated
and
ready to
use
when
received.
It
operates
in
one
compartment
of
a
TM
500-
series power module. Refer
to
the power
module
i
nstruc
tion manual
for
line voltage requirements and
power
module
operation.
Turn
the
power
module
off
before
inserting
the
plug-
in;
otherwise,
damage
may
occur
to
fhe
plug-in
drcuitry.
Check to
see
that
the
plastic barriers on the inter-
connecting
jack
of
the selected
power
module
compart-
ment
match
the cut-outs in
the
DM
505 circuit
board
edge
connector.
Align
the
DM
505
chassis
with
the upper
and
lower
guides
(see
Fig.
2-1)
of
the
selected
compartment.
Push
the
DM
505
in
and
press
firmly
to
seat
the
circuit
board
in
the interconnecting
jack.
Pull
out
the
power
switch
Qn
the
power
module.
One
or
more
characters
in
the
LED
display should now
be
visible.
To
remove the
DM
505,
pull
on
the
release
latch
(located
in
the
lower
left
corner)
until
the
i
ntereonnecting
jack
disengages and the
DM
505 slides
out.
Rg.
2-1.
DM
505
Installation
and
remova!.
CONTROLS
AND
CONNECTORS
DISPLAY
@
Display
3
1/2
digit
LED
readout with decimal point
auto-
matically positioned by
the
range pushbuttons.
VOLTS
Selects
dc
voltage function.
@VOLTS
AC
pushbutton
Selects
ac
voltage function.
RESISTANCE
@
kn
pushbutton
Selects resistance function,
Pushbutton
In
selects full scale probe
tip
voltage
of
0.2
V
in all ranges. Pushbutton
out
selects full scale
probe
tip
voltage
of
2
V
except
in the
200
R
range
which is
0.2
V.
CURRENT
Selects dc current function.
@m~
AC
pushbutton
Selects
ac
current function.
CONNECTORS
A
Refer to Input Connections in theoperating Instruc-
tions.
@
mA
Connector
Use
with
LOW
input connector for current
measurements.
@
LOW
Connedw
Common input
connector
for all measurements.
@
voLTwn
Connector
Use
with
LOW
input
connector
fw
voltage
and
resistance measurements.
@
Ground
Binding
Post
Chassis ground.
RANGE
SELECTION
@
Range
Select
Pushbuttons
Select
the
desired measurement range.
@
Release
Latch
Pull
to
remove plug-in.
@
IN
PUT
EXT- I NT
Pushbunon
Refer
to
Input Connections
in
the
Operating Instruc-
tions.
Pushbutton
out
{EXTI
selects front
panel
input con-
nectors;
pushbutton
in
(INTI selects rear interface
input
terminals for
dc
and
ac
volts
and
resistance
measurements only.
OPERATORS
FAMILIARIZATION
General
Operating
lnf
ormation
With the DM
505
properly installed
in
the
power
module, allow thirty minutes warmuptimefor operation
to
specified
accuracy. Select
the
desired measurement f unc-
tion
and
range.
When
the
value
of
the
quantity
being
measured
is
unknown,
setect
the highest
range first.
Decrease
the
range
setting
until the display blinks to
indicate over-range. Then
change
the range pushbutton
to the
next
higher range. This method obtains
maximum
resolution.
1
WARNING
)
To
avoid
shock
hazard
from
voltages
measured
by
the
DM
505:
I,
Avoid
all
contact
with
the
voltage
source
being
meas
wed.
2.
Disconnect
probes
from
circuit
undertest
before
disconnecting
probes
from the
DM
505,
or
before
removing
the
DM
505
from
the
power
module.
Operating Instructions-DM
505
cor
Fig.
2-2.
Front panel controls and connectors.
Input
Connections
A
DC
Current
Measurements
The INPUT EXT-INT pushbutton selects front panel
or
rear Interface input.
Three input connectors provide front panel measure-
ment connections. The
YOLTS/Tr
and
LOW
input connec-
tors are used for
ac
or dc voltage
or
resistance
measurements.
The
mA and LOW input connectors are
used for
ac
or
dc
current measurements. Rear interface
pins 28B
(HI)
and
T8A
(LO) are used for rear interface
voltage and resistance measurements.
Norml
rneasure-
rnent conditions
are
with the
LOW
terminal ungrounded.
A
connection between the
LOW
input connector and the
ground terminal may be made to
referencetheinput tothe
DM
505
chassis
ground.
Use
caution,
as
the Lowterminal
is then connected
ta
earth ground through the power
module three-wire
power
cord. False readings may
be
obtained due to ground loops.
The
maximum
input
voltage
is
I
kV
peak
at
the
front
panel
connectors and
200
Y
peak
at
the
rear
inter-
face
connectors.
The
front
panel
VOLTSIfl
and
LOW
connectors
may
be
floated
at
I
kVmaximum
above
ground.
fhe
rear
input
connector
200
V.
Sine-wave
Response
The
DM
505
responds to the average value
of
an
ac
or
dc current or voltage and the readout displays the
sinusoidal rms value. The effective or rms
value
of a sine-
wave
is
0.707 times the peak voltage or current.
The
average
value
is
0
636
of
the
peak
value. The scale factor of
the
DM
505 is 0.636/0.107 or 0.9.
To
obtain the average
value
of
a
sinusoidal input voltage or current, multiply the
DM
505
readout
by
0.9.
'DC
Voltage
Measurements
Press the VOLTS
DC
pushbutton and an appropriate
range button. Apply the voltage to be
measured
to
the
LOW and
VOLTS/n
input connectors. 0 bserve
the
max-
imum input voltage ratings
as
indicated on the front panel.
The readout displays
a
f
if the input to the VOLTS/R
connector
is
positive with respect to the
LOW
input
connector.
A
-
is
displayed
if
the input
at
the
LOW
input
connector
is
the more positive. With the
LOW
and
VOLTS/n input connectors shorted, the display reads
zero
+
one count.
Press
the
mA
DC
pushbutton
and
an appropriaterange
button. Connect the
dc
current to
be
measured tathe
LOW
and
mA
input connectors. Conventional current flowing
into the
mA
connector and out
of
the
LOW
connector
(or
electron
flow
into the
LOW
connector and out
of
the mA
connector) indicates
a
+
on the display. The input
resistance in the current mode is listed in Table
2-T.
Table
2-1
AC
Voltage
and
Current
Measurements
CURRENT
MODE
INPUT
RESISTANCE
For ac voltage measurements, press the VOLTS
AC
pushbutton and an appropriate
range
button. Connect
the
unknown voltage
to
the LOWand VOLTS/R input connec-
tors.
Range
200 PA
2
mA
20
mA
200
mA
2000
mA
To measure
ac
current,
press
the
rnA
AC
pushbutton
and an appropriate range button. Connect the unknown
ac current
to
be measured to the
mA
and
LOW
input
connectors. The input resistance in
the
current mode
is
listed in Table 2-1.
Approximate
Resistance
1001
R
100.4
R
10.25
R
1.2
R
0.25
R
Resistance
Measurements
Press the
kfl
pushbutton and
an
appropriate
range
button.
Also,
press
the
HI
n-LO
fl
button for
a
maximum
full-scale probe-tip voltage
of
0.2
V.
Release the HI n-LO
R
button
(out
position) for a maximum full-scale probe-tip
voltage
of
2 V (except on the
200
fl
range which is
0.2
V).
The
low probe-tip voltage is
useful
for
making
in-circuit
measurements without forward-biasi ng silicon diodes or
transistor junctions.
The
kR
mode
provides an accurate constant current
at
the
LOW
and VOLTS/n input connectors. Refer to Table
2-1
for the value
of
current and maximum voltages across
the input terminals for full
scale
display readings (instru-
ment
not
over-ranged). The maximum (open circuit)
voltage available from the
YOLTS/fl terminal to the LOW
terminal
in
the
resistance
mode
is about
+6
V.
REV
A
OCT
1979
Operating
rnstructions-DM
505
Ta'ble
2-2
If
the Tektronix instrument is
to
be
shiw~ed
to
a
. .
OHMMETER
SOURCE
CURRENT
AND
VOLTAGE
Tektronix
Service Center
for
service or repair, attach
a
tag
showing owner
(with
address) and the name
of
an
Packaging
Information
individual
at
your firm
that
can
be
contacted. Include
the
complete instrument serial number and a description of
the
service required.
Save
and
re-use
the
package
in which your i nstrurnent
was
shipped. If
the
original packaging
is
unfit
for
use
or
not available, repackage
the
instrument
as
follows:
Surround
the
instrument with polyethylene
sheeting
to
protect the finish of
the
instrument. Obtain
a
carton
of
corrugated cardboard
of
the
correct
carton
strength
and having
inside dimensions
of
no
less
than 6 inches
more
than the instrument dimensions. Cushion the
instrument
by
tightly packing 3 inches
of
dunnage
or
urethane foam between carton and instrument on
all
sides.
Seal
the
carton with shipping tape or
an
in-
dustrial stapler.
A
list
of
standard aecessaries
(and
part numbers)
is
The
carton
test
strength
for
this instrument is
200
located
in
the Replaceable Mechanical
Parts
list.
pounds
per square inch.
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