Bosch MMD 540H User manual

MMD 540H
Hybrid Multimeter
Instruction Manual

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
540H Hybrid Multimeter | Table of Contents | 1
Contents
2 Introduction
3 Safety
7 Getting Started
8 Digital LCD Display
8 Front Panel Description
9 LCD Symbols
10 Push-button Functions
10 Mode Button
10 Manual range & Stroke 4/2,Hz,%,ms,CYL Button
10 Data Hold
11 Peak Hold
12 MAX/MIN
12 Backlight Button
13 Meter Functions
13 Voltage (V)
14 Resistance ()
15 Diode Check( )
16 Capacitance(CAP)
17 Audible Continuity ( )
18 AC or DC Current (A)
19 Temperature (°C/°F)
20 Frequency (Hz)
21 Dwell ( )
22 Duty Cycle (%)
23 Ms – PULSE.
25 RPM ( )
26 General Specifications
27 Electrical Specifications
30 Replacing the Battery
30 Battery Installation
31 Replacing the Fuses
32 Trouble Shooting
33 Warranty Information
MMD 540H Hybrid Multimeter | Languages
Languages
1 English
35 Spanish
69 French

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
This chapter covers brief, introductory information, You will find:
fSafety precautions
Safety
DANGER
fEngines 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.
fSet 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.
fWear 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.
fVoltage between any terminal and ground must not exceed 600V
DC or 600V AC.
fUse caution when measuring voltage above 25V DC or 25V AC.
fCircuit tested must be protected by a 20A fuse or circuit breaker.
fDo not use the meter if it has been damaged.
fDo not use the test leads if the insulation is damaged or if metal
is exposed.
MMD 540H Hybrid Multimeter | Safety | 32 | MMD 540H Hybrid Multimeter | Introduction

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Safety Cont’d…
DANGER
fAvoid electrical shock: do not touch the
test leads, tips or the circuit being tested.
fDo not try a voltage measurement with the
test leads in the 20A or the mA terminal.
fWhen 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.
fChoose 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.
fWhen measuring current, connect the meter in series with the
load.
fNever connect more than one set of test leads to the meter.
fDisconnect the live test lead before disconnecting the common
test lead.
fThe 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…
fFuse Replacement
4| MMD 540H Hybrid Multimeter | Safety MMD 540H Hybrid Multimeter | Safety | 5
Safety Cont’d…
IMPORTANT
fTo maintain accuracy of the meter, replace the discharged
battery immediately when the symbol “BAT” appears on the
meter display.
fAvoid measuring error from outside interference. Keep the meter
away from spark plug or coil wires.
fAvoid damaging the meter when testing voltage. Disconnect the
test leads from the test points before changing functions.
fDo not exceed the limits shown in the table below:
Function Terminal Input limit
DC/AC Volts,
Ohm†/Continuity /
Diode,CAP.,IR- TEMP.
Adaptor, Type-K
TEMP.,Hz,%Duty, Ms
Dwell, RPM
V-Ω-RPM 600VoltsAC DC
AC/DC μA mA μA / mA 400mA DC/AC
AC/DC20A 20A *20A DC/AC
*20 Amp measurement for 30 seconds maximum.
†Ohms can not be measured if voltage is present, ohms can be
measured only in a non-powered circuit. However, the meter is
protected to 600 volts.

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Getting Started
This chapter will help you get started. It describes the basic
functions of the Meter.
MMD 540H Hybrid Multimeter | Getting Started | 76 | MMD 540H Hybrid Multimeter | Safety
Safety Cont’d…
Hybrid electric, plug-in hybrid and electric vehicles have high-
voltage components. Use this tool on these vehicles only if:
fYou are specially trained in high-voltage electrical system repair
on hybrid electric, plug-in hybrid and electric vehicles.
fYou have already read and are following the OEM manufacturer’s
approved hybrid electric, plug-in hybrid and electric vehicle
service. These procedures must be followed due to the high
voltages in hybrid electric, plug-in hybrid and electric vehicles.
fYou are using the CAT III / 1000 V rated leads included with this
Multimeter kit.
fYou are wearing proper protective gear, including Class 0 Type
I electric service gloves that are free from defects / faults and
that meet ASTM D120 Standards and protect up to 1000 Volts
AC / 1500 Volts DC.
Failure to follow these steps could
result in shock or electrocution,
causing severe injury or death.
DANGER
Risk of Shock, Electrocution, Severe Injury or Death

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Meter Basics
1.Digital LCD display
Display features:
1a. Symbols to identify function
1b. Four character digital
display
The digital display is best for
stable inputs. The bar graph is
best for rapidly changing inputs.
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
measure; Amps, Volts, Ohms,
TEMP, Hz, RPM, Cap, mS and
Dwell.
The Black test lead is used in
the Common(COM) terminal for
all tests.
LCD Display Symbols and Annunciators
-8.8.8.8 LCD digits
Continuity
BAT Low Battery
Diode
DATA HOLD Data Hold
AUTO AutoRanging
AC Alternating Current or Voltage
DC Direct Current or Voltage
n nano (10-9) (capacitance)
µ micro (10-6) (amps, cap)
m milli (10-3) (volts, amps)
A Amps
k kilo (103) (ohms)
F Farads (capacitance)
M mega (106) (ohms)
Ω Ohms
V Volts
Hz Hertz (frequency)
% Percent (duty ratio)
ºF Degrees Fahrenheit
ºC Degrees Centigrade
IR TEMP Infrared Temperature
8| MMD 540H Hybrid Multimeter | Meter Basics MMD 540H Hybrid Multimeter | LCD Display Symbols | 9

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Push–button Functions
Mode Button
Press the mode pushbutton to select the
following functions; DC/AC Voltage, DC/
AC Current Resistance, Diode, Continuity &
Capacitance
Manual Range & Stroke 4/2(DIS), z,
%, ms +, CYL Button
Press to this button to select: STROKE
4, 2DIS, Hz ,%, ms+ , CYL range & V/A/
Resistance manual Range
Manual Ranging
The meter turns on in the autoranging
mode.
Press the Range button to go to manual
ranging.
The display icon “ ” will appear. Each press of the
range button will step to the next range as indicated by
the units and decimal point location. Press and hold the
Range button for two seconds to return to autoranging.
Data Hold
The Data Hold function allows the meter
to “freeze” a measurement for later
reference.
1. Press the DATA HOLD button to “freeze”
the reading on the indicator. The
indication of “HOLD” will appear in the
display.
2. Press the DATA HOLD button again to return to
normal operation.
Peak Hold
The Peak Hold function captures the peak
AC or DC voltage or current. The meter
can capture negative or positive peaks as
fast as 1 millisecond in duration.
1. Set the function switch to the Amps or
Volts.
2. Press and Hold the PEAK button until
“CAL” appears in the display. This procedure will zero the range
selected & the meter will go into manual ranging mode.
3. Press the PEAK button, Pmax will display.
4. The display will update each time a higher positive peak occurs.
5. Press the PEAK button again, Pmin will display. The display will
now update and indicate the lowest negative peak.
6. To return to normal operation, press and hold the PEAK button
until the Pmin or Pmax indicator switches off.
NOTE: If the Function switch position is changed after a
calibration the Peak Hold calibration must be repeated for the
new function selected.
MMD 540H Hybrid Multimeter | Push-button Functions | 1110 | MMD 540H Hybrid Multimeter | Push-button Functions

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
MAX/MIN
1. Press the MAX/MIN key to activate the
MAX/MIN recording mode. The display
icon “MAX or MIN” will appear. The
meter will go into manual ranging
mode & display and hold the maximum
or minimum reading and will update
only when a new “max or min” occurs.
2. Press the MAX/MIN key and a blinking
“MAX MIN” will appear. The meter will display the present
reading, but will continue to update and store the max and min
readings.
To exit MAX/MIN mode press and hold the MAX/MIN key for 2
seconds.
Backlight Button
1. Press the BACKLIGHT button to turn
the backlighting ON.
2. Press the BACKLIGHT button again to
turn the backlighting OFF.
12 | MMD 540H Hybrid Multimeter | Push-button Functions MMD 540H Hybrid Multimeter | Meter Functions | 13
Meter Functions – Voltage (V)
fSelect the Volts “V” range with
the rotary switch.
fThe meter will automatically
select the best voltage (V)
range.
fSelect DCV or ACV with the
MODE button.
Insert:
fBlack lead in COM terminal.
fRed lead in V-Ω-RPM 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
measured in parallel (Red probe
measuring circuit from power
source).
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
Milliamp (mA) terminal, the meter can be damaged and risk of
personal injury.
Black– Red+

Black– Red+
Black– Red+
Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
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.
fSelect the Resistance
“Ω” range with the rotary
switch.
fSelect the Resistance “Ω”
function with the Mode
button. Please note, the
unit defaults to resistance.
Insert:
fBlack lead in COM
terminal.
fRed 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
fSelect the Diode Check “ ”
function with the rotary switch and
mode button.
Insert:
fBlack lead in COM terminal.
fRed 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
MMD 540H Hybrid Multimeter | Meter Functions | 1514 | MMD 540H Hybrid Multimeter | Meter Functions

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Meter Functions – Capacitance (CAP)
IMPORTANT: Turn the power OFF to the test circuit
fSelect the Capacitance “CAP”
function with the rotary switch
and mode button
Insert:
fBlack lead in COM terminal.
fRed lead in V-Ω-RPM terminal
CAUTION: When checking in-
circuit capacitance, be sure that
the circuit has all power removed
and all capacitors are fully
discharged.
Touch the test lead probes across
the capacitance circuit to be tested.
Read the measured value from the
LCD display.
NOTE:
1. The bar graph is disabled in
capacitance measurement mode.
However, since the measurement
time of 4mF and 40mF modes
is quite long (3.75s and 7.5s
respectively, to be precise), the bar graph is instead used to
display the time required to accomplish the measurement.
2. In order to obtain an accurate reading, a capacitor must be
discharged before measurement begins. The meter has a built-
in discharge mode to automatically discharges the capacitor. In
discharge mode, the LCD displays “DIS.C”
3. Discharging through the chip is quite slow. We recommend the
user to discharge the capacitor with some other apparatus.
16 | MMD 540H Hybrid Multimeter | Meter Functions
Meter Functions – Audible Continuity ( )
IMPORTANT: Turn the power OFF
on the test circuit
fSelect the Audible Continuity
“ ” function with the rotary
switch and mode button.
Insert:
fBlack lead in COM terminal.
fRed lead in V-Ω-RPM terminal.
Connect one test probe to each
end of the circuit to be tested.
fCircuit complete, the meter will
beep continuously.
fCircuit open, there is no beep
and the display shows to OL
(over limit).
MMD 540H Hybrid Multimeter | Meter Functions | 17
Black– Red+
Circuit open
- no beep
Black– Red+

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Meter Functions – AC or DC Current (A)
IMPORTANT: All current measured flows
through the meter.
It is important that you do not:
1. Measure current greater than 600
Volts AC or DC, with respect to
ground.
2. Do Not Exceed 30 seconds when
measuring continuous current
between 1A-20A. Allow five minutes
for cool down before continuing.
fSelect the “20A” or “mA” range with
the rotary switch.
fPress the Mode button to select AC or
DC.
Insert:
fBlack lead in COM terminal.
fRed 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:
fThe Red probe to the side of the circuit closest to the power
source.
fThe Black probe to the side of the circuit to ground.
fTurn the power ON and test.
NOTE: Current must always be measured with the meter test
probes connected in series, as described
Meter Functions – Temperature (°C/°F )
IMPORTANT: To avoid heat
damage to the meter, keep
it away from sources of
very high temperature. The
life of the Temperature
Probe is also reduced
when subjected to very
high temperatures. Probe
operating range is –58° to
482°F.
fSelect the Temperature
“°C or °F” function with
the rotary switch.
fInsert the temperature
probe connector into
the K-type thermocouple
adapter. Insert the
adapter into the front of
the meter as shown.
fTouch the end of the temperature sensor to the area or surface
of the object to be measured.
18 | MMD 540H Hybrid Multimeter | Meter Functions MMD 540H Hybrid Multimeter | Meter Functions | 19
Black–Red+
Round
ide
Temperature
Sensor
Temperature
Probe

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Meter Functions – Frequency(Hz)
fSelect the “Hz” Frequency
function with the rotary
switch.
Insert:
fBlack lead in COM terminal.
fRed lead in V-Ω-RPM
terminal.
Connect the Black test probe to
ground.
Connect the Red test probe
to the “signal out” wire of the
sensor to be tested.
20 | MMD 540H Hybrid Multimeter | Meter Functions
Meter Functions – Dwell ( )
fSelect the “DWELL” function
with the rotary switch.
Insert:
fBlack lead in COM terminal.
fRed lead in V-Ω-RPM terminal.
Connect the Black test probe to
ground.
Connect the Red test probe to
the wire that connects to the
breaker points (see illustration).
MMD 540H Hybrid Multimeter | Meter Functions | 21
Black– Red+
“Signal Out”
Side
Ground
Side
“Voltage In”
Side
Black– Red+
To breaker
Points

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Meter Functions – Duty Cycle (%)
fSelect the “%DUTY”
Cycle function with the
rotary switch.
Insert:
fBlack lead in COM
terminal.
fRed lead in V-Ω-RPM
terminal.
Connect the Black test
probe to ground.
Connect the Red test probe
to the signal wire circuit.
The illustration for a mixture
control solenoid is shown
with the metering rod in the
closed position. The meter
will display the percentage
of time the plunger is in the
closed position. (low duty
cycle) during one duty cycle.
22 | MMD 540H Hybrid Multimeter | Meter Functions
Meter Functions – ms-PULSE (Pulse Width)
& ms-PERIOD (Period)
Pulse Width is the length of time an actuator is energized. For
example, fuel injectors are activated by an electronic pulse from the
Engine Control Module (ECM).
This pulse generates a magnetic field that pulls the injectors nozzle
valve open.
The pulse ends and the injector nozzle is closed.
This open to close time is the Pulse Width and is measured in
milliseconds( ms).
The most common automotive application for measuring pulse
width is on fuel injectors.
You can also measure the pulse width of the fuel mixture control
solenoid and the idle air control motor.
Measuring Pulse Width on Port Fuel injectors is described on the
following page.
(continued on next page)
MMD 540H Hybrid Multimeter | Meter Functions | 23
Black– Red+
Mixture
Control
Shown

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
(continued from previous page)
To measure pulse width (mS):
fSelect the “mS-Pulse”
function with the rotary
switch .
fPress the ±TRIG button for
2 seconds until the negative
(-) trigger slope is displayed
on the upper left side of the
display.
NOTE: The applied time for
most fuel injectors is displayed
on the negative (-) slope.
Insert:
fBlack lead in COM jack.
fRed lead in V-Ω-RPM jack.
Connect:
Jumper wires between the
fuel injector and the harness
connector.
Black test probe to a good
ground at the fuel injector or the negative (-) vehicle battery post.
Red test probe to the fuel injector solenoid driver input on the
jumper cable.
Start the engine. A pulse width in milliseconds should be read.
NOTE: Initially, the unit will read “OL”, then readings will descend
and stabilize to the actual pulse width. If “OL” remains, re-check
your connections.
Meter Functions – RPM/×10RPM
fSelect the RPM range with the rotary
switch.
OR
fSelect the×10RPM range with the rotary
switch (1,000 to 12,000 RPM). Multiply
the displayed reading by ten to get
actual RPM.
Press STROKE / DIS button to select
through RPM for 4-stroke, RPM for
2-stroke and DIS ignitions.
Insert the inductive pickup connecting
terminals into the meter.
fBlack lead in COM terminal.
fRed lead in V-Ω-RPM terminal.
Connect the inductive pickup to a spark
plug wire. If no reading is received, unhook
the clamp, turn it over and connect again.
NOTE:
fPosition the inductive pick-up as far away from the distributor
and the exhaust manifold as possible.
fPosition the inductive pick-up to within six inches of the spark
plug or move it to another plug wire if no reading or an erratic
reading is received.
RPM 4: For RPM of 4-stroke engines which have 1 ignition on every
4 engine strokes
RPM 2: For RPM of DIS ( Distributorless lgnition System) & 2-stroke
engines which Have 1 ignition on every 2 engine strokes
NOTE: The rpm pick-up has an adjustable sensitivity switch that
can also be used to correct an unstable reading.
24 | MMD 540H Hybrid Multimeter | Meter Functions MMD 540H Hybrid Multimeter | Meter Functions | 25
Black– Red+
Good Ground
Jumper Leads From
Port Fuel Injector
Mixture
Control
Shown

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
General Specifications
The instrument complies with: IEC 1010-1 EN61010-1.
Insulation: Class2, Double insulation.
Overvoltage category: CATIII1000V/CATIV600V.
Display: 4000 counts LCD display with function indication.
Polarity: Automatic, (-) negative polarity indication.
Overrange: “OL” mark indication.
Low battery indication: The “BAT” is displayed when the battery
voltage drops below the operating level.
Measurement rate: 2 times per second, nominal.
Auto power off: Meter automatically shuts down after approx. 30
minutes of inactivity.
Operating environment: 0° C to 50° C (32° F to 122° F) at < 70 %
relative humidity.
Storage temperature: -20° C to 60° C (-4° F to 140° F) at < 80 %
relative humidity.
For inside use, max height: 2000m
Pollution degree: 2
Power: One 9V battery , NEDA 1604, IEC 6F22.
Dimensions: 182 (H) x 82 (W) x55 (D) mm
Weight Approx.: 375g.
26 | MMD 540H Hybrid Multimeter | General Specifications
Electrical Specifications
*Accuracy is given as±([% of reading]+[number of least significant
digits]) at 18° to 28°(65°F to 83°F), with relative humidity up to 70%.
RPM (Tach)
Range Resolution Accuracy
RPM 4 600~4000 RPM 1 RPM
±2 % of rdg ±4 dgts
1000~12000 RPM
(X10 RPM)
10 RPM
RPM 2/DIS 300~4000 RPM 1 RPM
1000~6000 RPM
(X10 RPM)
10 RPM
Effect Reading: >600 RPM
Dwell Angle
Cylinder Range Resolution Accuracy
4CYL 0~90.0° 0.1° ±2.0% of rdg ±4 dgts
5CYL 0~72.0°
6CYL 0~60.0°
8CYL 0~45.0°
DC Voltage
Range Resolution Accuracy
400.0mV 0.1mV ±0.5% of rdg ±2 dgts
4.000V 1mV ±1.5% of rdg ±2 dgts
40.00V 10mV
400.0V 100mV
600V 1V ±1.8% of rdg ±2 dgts
Input Impedance: 10M
AC Voltage
Range Resolution Accuracy
4.000V 1mV ±1.0% of rdg ±3 dgts
40.00V 10mV ±1.5% of rdg ±3 dgts
400.0V 100mV
600V 1V ±2.0% of rdg ±4 dgts
Input Impedance: 10M.
Frequency Range: 50 to 60Hz
MMD 540H Hybrid Multimeter | Electrical Specifications | 27

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
DC Current
Range Resolution Accuracy
40.00mA 10uA ±1.5% of rdg ±3 dgts
400.0mA 100uA
20A 10mA ±2.5% of rdg ±5 dgts
Overload Protection: 0.5A / 250V and 20A / 250V Fuse.
Maximum Input: 400mA dc or 400mA ac rms on uA / mA ranges,20A dc or
ac rms on 20A range.
AC Current
Range Resolution Accuracy
40.00mA 10uA ±1.8% of rdg ±5 dgts
400.0mA 100uA
20A 10mA ±3.0% of rdg ±7 dgts
Overload Protection: 0.5A / 250V and 20A / 250V Fuse.
Frequency Range: 50 to 60 Hz
Maximum Input: 400mA dc or 400mA ac rms on uA / mA ranges, 20A dc or
ac rms on 20A range.
Resistance
Range Resolution Accuracy
400.0 0.1 ±1.2% of rdg ±4 dgts
4.000k 1 ±1.0% of rdg ±2 dgts
40.00k 10 ±1.2% of rdg ±2 dgts
400.0k 100
4.000M 1k
40.00M 10k ±2.0% of rdg ±3 dgts
Capacitance
Range Resolution Accuracy
4.000nF 1pF ±5.0% of rdg±50 dgts
40.00nF 10pF ±5.0% of rdg ±7 dgts
400.0nF 0.1nF ±3.0% of rdg ±5 dgts
4.000uF 1nF
40.00uF 10nF
400.0uF 0.1uF
4.000mF 0.001mF ±10% of rdg ±10 dgts
40.00mF 10.00mF
Frequency
Range Resolution Sensitivity Accuracy
4.000kHz 1Hz >5V RMS ±1.5% of rdg ±3 dgts
40.00kHz 10Hz
400.0kHz 100Hz
40.00MHz 1kHz >10V RMS ±2.0% of rdg ±4 dgts
Duty Cycle
Range Resolution Accuracy
0.1%~99.9% 0.1% ±2% of rdg ±2 dgts
Pulse width: >100us, <100ms;
Frequency width: 5Hz – 100kHz
Sensitivity: >5V RMS
Pulse Width
Range Resolution Accuracy
1.0~ 20.0ms 0.1ms ±2% of rdg ±20 dgts
Type-K Temperature
Range Resolution Accuracy
-30° C~ 1000° C 1° C ±3% of rdg ±5° C/8° F (Meter
only, probe accuracy not
included)
-22° F~1832° F 1° F
Sensor: Type K Thermocouple
Diode Test
Test current Resolution Accuracy
1.0mA typical 1 mV ±5% of rdg ±15 dgts
Open circuit voltage: 3.0V dc typical
Audible continuity
Audible threshold: Less than35 Test current: <1mA dc typical
MMD 540H Hybrid Multimeter | Electrical Specifications | 2928 | MMD 540H Hybrid Multimeter | Electrical Specifications

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Maintenance
Replacing the Battery
WARNING: To avoid electric shock, disconnect the test leads
from any source of voltage before removing the battery door.
1. When the batteries become exhausted or drop below the
operating voltage, “BAT” will appear in the right-hand side of the
LCD display. The battery should be replaced.
2. Follow instructions for installing battery. See the Battery
Installation section of this manual.
3. Dispose of the old battery properly.
WARNING: To avoid electric shock, do not operate your meter
until the battery door is in place and fastened securely.
Battery Installation
WARNING: To avoid electric shock, disconnect the test leads
from any source of voltage before removing the battery door.
1. Disconnect the test leads from the meter.
2. Open the battery door by loosening the screw using a Phillips
head screwdriver.
3. Insert the battery into battery holder, observing the correct
polarity.
4. Put the battery door back in place. Secure with the two screws.
WARNING: To avoid electric shock, do not operate the meter
until the battery door is in place and fastened securely.
NOTE: If your meter does not work properly, check the fuses and
battery to make sure that they are still good and that they are
properly inserted.
Replacing the Fuses
WARNING: To avoid electric shock, disconnect the test leads
from any source of voltage before removing the rear cover (fuse
door).
1. Disconnect the test leads from the meter and any item under
test.
2. Open the fuse door by loosening the screws on the rear cover
using a Phillips head screwdriver.
3. Remove the old fuse from its holder by gently pulling it out.
4. Install the new fuse into the holder.
5. Always use a fuse of the proper size and value (0.5A/250V -Ø5
x 20 , fast blow for the 400mA range, 20A/250V –Ø6.3 x 32 fast
blow for the20A range). Commonly available at local electronics
retailers and Radio Shacks.
6. Put the fuse door back in place. Insert the screw and tighten it
securely.
WARNING: To avoid electric shock, do not operate your meter
until the fuse door is in place and fastened securely.
30 | MMD 540H Hybrid Multimeter | Maintenance MMD 540H Hybrid Multimeter | Maintenance | 31

Robert Bosch LLC MMD 540H Instruction Manual | Version 1 | December 2010 MMD 540H Instruction Manual | Version 1 | December 2010 Robert Bosch LLC
Trouble Shooting
1. Meter will not turn ON.
fCheck the battery contacts for a tight fit.
fCheck for a minimum battery voltage of 8.0 volts.
2. Ampere reading is erratic or there is no reading at all.
fDisassemble the meter back cover as per the fuse
replacement instructions on page 31 and test the fuses for
continuity with another meter.
3. Meter reading is erratic.
fPrinted circuit board damaged from handling with hands.
fLow battery.
f“Blown” fuse.
fOpen circuit in a test lead (frayed or broken wire).
4. Meter readings do not change.
f“Hold” feature is still toggled ON.
Warranty Information:
This product is warranted to be free of defects for one year. If this
product fails during the first 12 months due to faulty material or
workmanship, it will be replaced or repaired free of charge, at the
discretion of the manufacturer.
NOTE: this one year warranty does not cover dead batteries and
blown fuses.
For warranty service and coverage, please return this product to
your supplier for processing and evaluation. OR, return it directly
to:
Bosch Diagnostics
Robert Bosch LLC
Repair Dept.
2800 S. 25th Ave.
Broadview, IL 60155-4594
For technical assistance and warranty return authorization call:
1-800-321-4889
fDefective units being returned to your supplier or to the factory
should include proof of purchase date.
fAny testers that do not function due to misuse or abuse will be
subject to “out of warranty service charges”.
32 | MMD 540H Hybrid Multimeter | Trouble Shooting MMD 540H Hybrid Multimeter | Warranty Information | 33

MMD 540H Manual de instrucciones | Versión 1 | Febrero 2008 Robert Bosch LLC
Contenido
36 Introducción
37 Seguridad
41 Para comenzar
42 Pantalla digital LCD
42 Descripción de la carátula
43 Símbolos de la pantalla
44 Funcionamiento de los botones
44 Botón de modo
44 Botón de rango manual, 4/2 tiempos, Hz, %, ms, CIL
44 Botón de memoria de datos
45 Memoria de valores máximos
46 MAX/MIN
46 Botón de luz de fondo
47 Funciones del multímetro
47 Voltaje (V)
48 Resistencia ()
49 Revisión de diodos ( )
50 Capacitancia (CAP)
51 Continuidad audible ( )
52 Corriente (A) de CA o CC
53 Temperatura (°C/°F)
54 Frecuencia (Hz)
55 Intervalo ( )
56 Factor de trabajo (%)
57 ms-PULSE
59 RPM ( )
60 Especificaciones generales
61 Especificaciones eléctricas
64 Reemplazo de la batería
64 Instalación de la batería
65 Reemplazo de los fusibles
66 Identificación y resolución de problemas
67 Información de la garantía
Multímetro híbrido MMD 540H | Contenido | 35

Robert Bosch LLC MMD 540H Manual de instrucciones | Versión 1 | Febrero 2008 MMD 540H Manual de instrucciones | Versión 1 | Febrero 2008 Robert Bosch LLC
Este capítulo consta de una breve introducción. Aquí encontrará:
fPrecauciones de seguridad
Seguridad
PELIGRO
fLos motores generan monóxido de
carbono que es inodoro, reduce la
velocidad con que una persona puede
reaccionar, y puede conllevar a una
lesión grave. Cuando el motor está en
funcionamiento, mantenga las áreas de
servicio BIEN VENTILADAS o conecte el
sistema de escape del vehículo al sistema
de extracción del taller.
fAplique el freno de mano y bloquee las
ruedas antes de verificar o reparar el
vehículo. Es especialmente importante
bloquear las ruedas en los vehículos de
tracción delantera; el freno de mano no se
aplica a las ruedas de tracción.
fUse protección para los ojos cuando esté
revisando o reparando el vehículo.
Es peligroso exceder los límites de este
multímetro. Esto lo expondría a sufrir alguna
lesión grave o incluso la muerte. Lea cuidadosamente y asegúrese
de comprender las precauciones y los límites nominales de este
multímetro.
fEl voltaje entre cualquier terminal y tierra no debe sobrepasar los
600 VCC ó 600 VCA.
fTenga precaución cuando mida voltajes por arriba de 25 VCC ó 25
VCA.
fEl circuito que revise debe contar con la protección de un fusible
o cortacircuitos de 20A.
fNo use el multímetro si se ha dañado.
fNo use los cables probadores si el aislamiento está dañado o si
hay metal expuesto.
36 | Multímetro híbrido MMD 540H | Introducción Multímetro híbrido MMD 540H | Seguridad | 37