CEM DT-9995 User manual

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AUTOMOTIVE MULTIMETER
WITH PC INTERFACE
INSTRUCTION MANUAL
Contents
Introduction……………………………………………………………………….1
Safety………………………………………………………………………………2
Getting Started…………………………………………………………………6
Meter Basics…………………………………………………………………………7
Digital and Analog display…………………………………………………………8
Function and Range Select…………………………………………………………9
Push-button Functions……………………………………………………10
Mode Button…………………………………………………………10
Range Select Button…………………………………………………………10
Range Exit ……………………………………………………………………10
+ TRIG Button………………………………………………………………10
Data Hold /Backlight Button………………………………………………12
MAX/MIN/RS232 Button……………………………………………………12
Relative Button………………………………………………………………12
Meter Functions
Voltage (V)……………………………………………………………………14
Resistance (Ω) ………………………………………………………………15
Diode Check( )……………………………………………………………16
Audible Continuity ( )……………………………………………………17
AC or DC Current (A) ………………………………………………………18
Temperature (℃/ 0F) ………………………………………………………19
Frequency (Hz) ……………………………………………………………20
Dwell ( )…………………………………………………………………21
Duty Cycle (%)………………………………………………………………22
Ms –PULSE& ms- PERIOD (ms) …………………………………………23
RPM ( ) ……………………………………………………………………25
Maintenance………………………………………………………………………26
Replacing The Battery……………………………………………………………26
Battery Installation…………………………………………………………………26
Replacing The Fuses………………………………………………………………27
Trouble Shooting…………………………………………………………………28
General Specifications…………………………………………………………29
Electrical Specifications…………………………………………………………30
Ready –to –Use Windows® Application Program………………………35
his chapter covers brief, introductory information, You will find:

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Safety precautions
Safety
DANGER
Engines produce carbon monoxide which
is odorless, causes slower reaction time,
and can lead to serious injury. When the
engine is operating, keep service areas
WELL VENTILATED or attach the vehicle
exhaust system to the shop exhaust
removal system.
Set the parking brake and block the
wheels before testing or repairing the
vehicle. It is especially important to block
the wheels on front-wheel drive vehicles;
the parking brake does not hold the drive
wheels.
Wear an eye shield when testing or
repairing vehicles.
Exceeding the limits of this meter is
dangerous.This will expose you to serious
or possibly fatal injury. Carefully read and
understand the cautions and the
specification limits of this meter.
Voltage between any terminal and ground
must not exceed 1000V DC or 750V AC.
Use caution when measuring voltage above 25V DC or 25VAC.
Circuit tested must be protected by a 20A fuse or circuit breaker.
Do not use the meter if it has been damaged.
Do not use the test leads if the insulation is damaged or if metal
is exposed.
CAP
Hz
20A
MAXevery
For
MAX
FUSED
15min.
FUSED
20AMAX
30sec.
400mA
500V
1000VDC
750VAC
MAX
-PERIOD
AmA
μ
DWELL
RPM
ms ¦¸
RPM
COMDWELL
ms-PULSE
%duty
V
x10RPM
OFF
24
¡ã
C
CAP¡ã
¦¸
Hz
20A
A
Fμ
mA
ms
TEMP.
%
CEM
TRIG¡À
1

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Safety Cont’d …
Danger
Avoid electrical shock: do not touch the test
leads, tips or the circuit being tested.
Do not try a voltage measurement with the
test leads in the 20Aor the mAterminal.
When testing for the presence of voltage or current, make sure
the meter is functioning correctly. Take a reading of a known
voltage or current before accepting a zero reading.
Choose the proper range and function for the measurement. Do
not try voltage or current measurements that may exceed the
ratings marked on the Function/Range switch or terminal.
When measuring current, connect the meter in series with the
load.
Never connect more than one set of test leads to the meter.
Disconnect the live test lead before disconnecting the common
test lead.
The mA and the 20A terminals are protected by fuses. To avoid
possible injury or damage, use only in circuits limited to 400mA
or 20A for 30 seconds.
See also …
Fuse Replacement
Safety Cont’d …
IMPORTANT
To maintain accuracy of the meter,replace the discharged battery
immediately when the battery symbol appears on the
meter display.
Avoid measuring error from outside interference.Keep the meter
away from spark plug or coil wires.
Avoid damaging the meter when testing voltage.Disconnect the
test leads from the test points before changing functions.
Do not exceed the limits shown in the table below:
Function
Terminal
Input limit
AC Volts
V-Ω-RPM
750Volts AC rms
DC Volts
1000Volts DC
Frequency
V-Ω-RPM
250VoltsAC/DC
Ohm(resistance)
V-Ω-RPM
250VoltsAC DC
Diode
AC/DC μA mA
μA / mA
400mAAC/DC
AC/DC20A
20A
*20AAC/DC
RPM
V-Ω-RPM
250Volts AC/DC
Duty Cycle(%)
Dwell angle
* 20 Amp measurement for 30 seconds maximum.
①Ohms can not be measured if voltage is present, ohms
can be measured only in a non-powered circuit. However,
the meter is protected to 250 volts.

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Notes:
Getting Started
his chapter will help you get started. It describes the basic
functions of the Meter.

7 8
Meter Basics
1.Digital and Analog display
Display features:
a.Four character digital display
b.Symbols to identify function
c. Analog bar graph
The digital display is best for
stable input. The bar graph is best
for rapidly changing input.
2.Function buttons
Press the button to select a
function. A symbol will display to
verify your choice.
3.Rotary Selector Switch
Turn this switch to select a
function or turn the meter OFF.
4.Volts Terminal
The Red test lead is used to
measureAmps, Volts, Ohms,
TEMP, Hz, RPM, Cap, mS and
Dwell.
The Black test lead is used
in the Common(COM) terminal for
all tests
Meter Basics Cont’d…
Digital and Analog display
AC DC Press the Mode button to select Alternating Current
(AC) or Direct Current (DC)
HOLD Press Hold to hold data display or resume testing.
RPM (Tach)
Negative Polarity Indicator
Continuity Test
When Dwell (# of cylinders) is selected with the
rotary switch.
Low Battery Replace the master battery when this
symbol displays.
Analog bar Graph display with polarity.
Units of measure:
Kilo (k=1,000)
Hertz (Hz)
Milli (M=1/1000,)
Volts (V)
mega(m=1,000,000)
ohms ( Ω )
dwell degrees
duty percent (%)

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Meter Basics Cont’d …
Function and Range Select
Turn the rotary switch in either
direction to select a function.
Most functions also have ranges.
Always select a range higher
than you expect the current or
voltage to be. Then select a lower
range if better accuracy is
needed.
If the range is too high, the
readings are less accurate.
If the range is too low, the
meter shows (over
limit).
Push–button Functions
Mode Button
Press the Mode button to toggle
between DC and AC in the
voltage & current measurements.
Range / # CYL Select
The range is automatically
selected by the meter. You can
also manually select a range or
DWELL (#CYL) range within a
function by pressing the
RANGE button.
Range Exit
To exit the RANGE mode and
return to autoranging, press and
hold the RANGE button for 2
seconds.
Note:
·If the range is too high, the
readings are less accurate.
·If the range is too low, the
meter shows OL (over limit).
+ TRIG
Toggles between a Negative (-)
and Positive (+) Trigger Slope
when the Meter is in the
ms-pulse, %duty cycle mode,
press this button down for 2
seconds to toggle between
a negative(-) and positive (+)
trigger slope.

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The change in the trigger slope is indicated by a + or –shown at
the lower left corner of the display.
The Meter defaults to a –trigger slope whenever the Meter is in
the Hz, %duty, ms-pulse, ms-period, dwell &RPM.
Once the trigger slope is selected, press this button repeatedly to
adjust trigger level if the meter reading is too high or unstable
The Trigger Level has five steps and is different for each function
combination.
Press this TRIG button to move one step at a time in order to
select a suitable trigger level.
The trigger level is indicated by the number above the “trig” symbol
at the lower left corner of the LCD.
The number of steps on the LCD is also a good indication of the
trigger level.
Function Step
Trigger Level
RPM, ms-Pulse,ms-Period,Dwell, %Duty,Hz
4
+7.2v
3
+4.1V
2
+2.1 V
1
+0.8 V
Data Hold/ Backlight
The Data Hold Feature stores the
last reading in memory.
Press the Data Hold button
once to hold the present
reading.
Press the Data Hold button
again to exit and resume
normal readings.
Press the Data Hold button for one
second to turn the backlight on
and press the button a second
time to turn the backlight off.
MAX/ MIN /RS232
Press MAX/MIN to enter, MAX MIN
recording mode. MAX/MIN function is
operative in manual range only!
Select the proper range before
activating MAX MIN to ensure that the
MZX/MIN reading will not exceed the
testing range. Press once to select MAX
Press again to select MIN and
press again release MAX/MIN
recording function.
Press this button down for 2 seconds to
select RS232 PC interface mode.
Relative Mode
The relative measurement feature
allows you to make measurements
relative to a stored reference value.
A reference voltage, current, etc.
can be stored and measurements
made in comparison to that value.

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The displayed value is the difference between the reference value
and the measured value.
1. Perform the measurement as described in the operating
instructions.
2.Press the REL button to store the reading in the display and
the "REL" indicator will appear on the display.
3.The display will now indicate the difference between the stored
value and the measured value.
4.Press the REL button to exit the relative mode.
Meter Functions - Voltage (V)
The meter will automatically
select he best voltage (V) range.
Select DCV or ACV with the
MODE button.
Insert:
Black lead in COM terminal.
Red lead in V-Ω-PRM terminal
Touch the Black probe to ground or
to the negative (-) circuit
Touch the Red probe to the circuit
coming from the power source
IMPORTANT: Voltage must be
measuring in parallel (Red probe
measuring circuit from power
source).
Accuracy
Selection of a lower range will
move the decimal point one
place and increase the accuracy.
An “OL”display means the
range is too low. Select the next
higher range.
Analog Bar Graph
The Bar Graph is easiest to
read when the data causes
the digital display to rapidly
change. It is also useful for
trend setting or directional
data.
WARNING
When measuring voltage,
be sure the Red test lead is
in the terminal marked “V”.
If the test lead is in an Amp
(A) or
Milliampere (mA) terminal,
you may be injured or the
meter damaged.

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Meter Functions –Resistance (Ω)
IMPORTANT: If you are testing
an application that has capacitors
in the circuit, be sure to turn the
power OFF on the test circuit and
discharge all capacitors. Accurate
measurement is not possible if
external or residual voltage is
present.
Select the resistance (Ω)
range with the rotary switch.
Select the resistance(Ω)
range with the button labeled
“RANGE”, if more accurate
measurement is desired.
Insert:
Black lead in COM terminal.
Red lead in V- Ω-RPM
terminal.
Touch the test lead probes across
the resistor to be tested.
Meter Functions –Diode Check ( )
IMPORTANT: Turn the power OFF to
the test circuit
Select the Diode Check ( )
function with the rotary switch.
Insert:
Black lead in COM terminal.
Red lead in V-Ω-RPM terminal.
Touch the Black test probe to the
negative (-) side of the diode.
Touch the Red test probe to the positive
(+) side of the diode.
Reverse the probes: Black to the positive
(+) side and Red to the negative (-) side.
Note:
A “good” diode will read low in one
`direction and high in the other direction
when the probes are reversed (or vice
versa).
A defective diode will have the same
reading in both directions or read
between 1.0 to 3.0 V. in both directions
Diode
- to +
Reverse
Probes
+ to -
Good
.4 to .9V
OL
OL
.4 to .9V
Bad
OL
1.0 to 3.0V
1.0 to 3.0V
OL
.4 to .9V
.4 to .9V
OL
OL
.000V
.000V

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Meter Functions –Audible Continuity ( )
IMPORTANT: Turn the power
OFF on the test circuit
Select the Audible Continuity
( ) function with the rotary
switch and mode button
Insert:
Black lead in COM terminal.
Red lead in V- Ω-RPM
terminal.
Connect one test probe to each
end of the circuit to be tested.
Circuit complete, the meter will
beep continuously.
Circuit open, there is no beep
and the display shows to OL
(over limit).
Meter Functions –AC or DC Current (A)
IMPORTANT: All current measured
flows through the meter.
It is important that you do not:
Measure current greater than
600 Volts AC or DC, with
respect to ground.
Do Not Exceed 30 seconds
when measuring continuous
current between 1A-20A.
Allow five minutes for cool
down before continuing.
Select the 20A.,mA or μA
range with the rotary switch.
Press the Mode button to
select AC or DC.
Insert:
Black lead in COM terminal.
Red lead in the 20A or mA
terminal (select 20A if you are
unsure of the current draw).
IMPORTANT: Turn OFF all power
to the circuit or disconnect the
circuit from the power source.
Connect:
The Red probe to the side of the
circuit closest to the power
source.
The Black probe to the side of
the circuit to ground.
Turn the power ON and test.
Note:
Current must always be
measured with the meter test
probes connected in series,
as described.