HT MULTITEST M72 User manual

©Copyright HT ITALIA 2006 Release EN 2.00 - 22/08/2006
ENGLISH
User’s manual

MULTITEST M72 - M73 - M74 - M75
EN - 1
1. SAFETY PRECAUTIONS AND PROCEDURES ....................................................................................................... 2
1.1. Preliminary instructions .................................................................................................................................... 2
1.2. During use........................................................................................................................................................ 3
1.3. After use........................................................................................................................................................... 3
1.4. Overvoltage categories - definitions ................................................................................................................. 3
2. GENERAL DESCRIPTION ........................................................................................................................................ 4
2.1. Working............................................................................................................................................................ 4
2.2. TRMS value and mean value - definitions........................................................................................................ 4
2.3. TRUE ROOT MEAN SQUARE VALUE and CREST FACTOR - definitions..................................................... 4
3. PREPARATION FOR USE ........................................................................................................................................ 5
3.1. Preliminary checks ........................................................................................................................................... 5
3.2. Power supply.................................................................................................................................................... 5
3.3. Calibration........................................................................................................................................................ 5
3.4. Storage ............................................................................................................................................................ 5
4. OPERATING INSTRUCTIONS.................................................................................................................................. 6
4.1. Instrument - Description ................................................................................................................................... 6
4.1.1. Turning on ................................................................................................................................................... 7
4.1.2. Auto Power Off ............................................................................................................................................ 7
4.1.3. Current measurement through external transducer..................................................................................... 7
4.1.4. Phase sequence and phase conformity measurement................................................................................ 7
4.2. HOLD, MAX/MIN/AVG, PEAK±........................................................................................................................ 8
4.2.1. HOLD .......................................................................................................................................................... 8
4.2.2. MAX/MIN/AVG ............................................................................................................................................ 8
4.2.3. PEAK±......................................................................................................................................................... 8
4.3. VHz: DC/AC voltage and frequency measurement (M73 and M75) .......................................................... 9
4.3.1. Frequency measurement .......................................................................................................................... 10
4.3.2. Anomalous cases which may occur during V Hz measurements ............................................................ 11
4.4. AHz: DC/AC current and frequency measurement ................................................................................. 12
4.4.1. Frequency measurement .......................................................................................................................... 13
4.4.2. Anomalous cases which may occur during A Hz measurements ........................................................... 14
4.5. Ω: Resistance measurement and continuity test ....................................................................................... 15
4.5.1. "CAL" mode............................................................................................................................................... 15
4.5.2. Anomalous cases which may occur during Ωmeasurement ................................................................ 16
4.6. : Phase sequence and conformity measurement ...................................................................................... 17
4.6.1. Anomalous cases which may occur during tests ................................................................................. 20
4.7. LAN: Cabling test (M75) ................................................................................................................................. 21
4.7.1. Anomalous cases which may occur during LAN tests ............................................................................... 22
4.7.2. SPLIT PAIRS - explication note................................................................................................................. 22
4.7.3. Cabling errors............................................................................................................................................ 23
4.8. Ω0.2A: Continuity test on earth, protective and equalizing potential conductors (M72, M74, M75) ............... 24
4.8.1. "CAL" mode............................................................................................................................................... 25
4.8.2. Anomalous cases which may occur during Ω0.2A tests............................................................................. 27
4.9. MΩ: Insulation resistance measurement test voltage 500V ..................................................................... 28
4.9.1. Anomalous cases which may occur during MΩtests ................................................................................ 29
4.10. RCD: Tests on AC type RCDs (M73, M74, M75) ........................................................................................... 30
4.10.1. Anomalous cases which may occur during RCD tests............................................................................. 31
4.11. Ra : Measurement of global earth resistance (M73, M74, M75)................................................................. 33
4.11.1. Anomalous cases which may occur during Ra tests............................................................................ 35
4.12. AUTO: Automatic cycle of measurements to test a plant (M74, M75)............................................................ 37
5. MAINTENANCE ...................................................................................................................................................... 39
5.1. General .......................................................................................................................................................... 39
5.2. Battery replacement ....................................................................................................................................... 39
5.3. Cleaning......................................................................................................................................................... 39
5.4. End of life ....................................................................................................................................................... 39
6. TECHNICAL SPECIFICATIONS ............................................................................................................................. 40
6.1. Characteristics ............................................................................................................................................... 40
6.1.1. Electrical.................................................................................................................................................... 42
6.1.2. Safety standards ....................................................................................................................................... 42
6.1.3. General specifications ............................................................................................................................... 42
6.2. ENVIRONMENT............................................................................................................................................. 42
6.2.1. Environmental conditions .......................................................................................................................... 42
6.2.2. EMC .......................................................................................................................................................... 42
6.3. ACCESSORIES ............................................................................................................................................. 42
7. SERVICE................................................................................................................................................................. 43
7.1. Warranty conditions ....................................................................................................................................... 43
7.2. After-sale service ........................................................................................................................................... 43

MULTITEST M72 - M73 - M74 - M75
EN - 2
1. SAFETY PRECAUTIONS AND PROCEDURES
This instrument complies with safety Standards EN61557 and EN61010-1 related to
electronic measuring instruments.
CAUTION
For your own safety and to avoid damaging the instrument follow the
procedures described in this instruction manual and read carefully all notes
preceded by this symbol .
When taking measurements:
)avoid doing that in humid or wet places - make sure that humidity is within the limits
indicated in section “environmental conditions”.
)avoid doing that in rooms where explosive gas, combustible gas, steam or excessive
dust is present.
)keep you insulated from the object under test.
)do not touch exposed metal parts such as test lead ends, sockets, fixing objects,
circuits etc.
)avoid doing that if you notice anomalous conditions such as breakages, deformations,
fractures, leakages of battery liquid, blind display etc.
)be particularly careful when measuring voltages exceeding 25V in particular places
(building yards, swimming pools, etc.) and 50V in ordinary places to avoid risks of
electrical shocks.
The following symbols are used:
CAUTION - refer to the instruction manual - an improper use may damage the
instrument or its components
DC or AC voltage or current
CAUTION for dangerious voltage. Risk of electric shock
Meter with double insulation
1.1. PRELIMINARY INSTRUCTIONS
)This instrument has been designed for use in environments of pollution degree 2.
)It can be used for tests on electrical installations of overvoltage category III 265V and
550V maximum rated interlinked voltage (and to earth).
)You are recommended to respect the usual safety regulations aimed at protecting you
against dangerous currents and protecting the instrument against improper use.
)Only the original test leads supplied along with the instrument guarantee compliance
with the safety Standards in force. They must be in a good conditions and, if
necessary, replaced with identical ones.
)Do not test nor connect to any circuit exceeding the specified overload protection.
)Do not take measurements under environmental conditions exceeding the limits
indicated in this manual.
)Make sure that batteries are correctly installed.
)Before connecting the test probes to the installation make sure that the right function is
chosen.

MULTITEST M72 - M73 - M74 - M75
EN - 3
1.2. DURING USE
CAUTION
An improper use may damage the instrument and/or its components or injure
the operator.
)Before selecting any function, first disconnect the test leads from the circuit under test.
)When the instrument is connected to circuits never touch any unused terminal.
)Do not measure resistance in presence of external voltages; although the instrument is
protected, an excessive voltage may cause malfunctioning.
CAUTION
If the “low battery” symbol is displayed during use interrupt testing and replace
batteries following the procedure described in paragraph 5.2.
1.3. AFTER USE
)Disconnect the test leads from the circuit under test and switch off the instrument.
)If you expect not to use the instrument for a long period remove batteries.
1.4. OVERVOLTAGE CATEGORIES - DEFINITIONS
Standard EN61010-1 (Safety requirements for electrical equipment for measurement, control
and laboratory use, Part 1: General requirements) defines what a measurement category
(usually called “overvoltage category”) is. At paragraph 6.7.4: Measuring circuits it says:
(OMISSIS)
Circuits are divided into the following measurement categories:
•Measurement category IV is for measurements performed at the source of the
low-voltage installation.
Examples are electricity meters and measurements on primary overcurrent
protection devices and ripple control units.
•Measurement category III is for measurements performed in the building
installation.
Examples are measurements on distribution boards, circuit breakers, wiring,
including cables, bus-bars, junction boxes, switches, socket-outlets in the fixed
installation, and equipment for industrial use and some other equipment, for
example, stationary motors with permanent connection to fixed installation.
•Measurement category II is for measurements performed on circuits directly
connected to the low voltage installation.
Examples are measurements on household appliances, portable tools and similar
equipment.
•Measurement category I is for measurements performed on circuits not directly
connected to MAINS.
Examples are measurements on circuits not derived from MAINS, and specially
protected (internal) MAINS-derived circuits. In the latter case, transient stresses are
variable; for that reason, the norm requires that the transient withstand capability of
the equipment is made known to the user.

MULTITEST M72 - M73 - M74 - M75
EN - 4
2. GENERAL DESCRIPTION
Dear Customer, the instrument you have purchased, whether used according to the
instructions given in this manual, will grant you accurate and reliable measurements.
Thanks to a development of newest conception assuring double insulation and overvoltage
category III you will enjoy the highest safety. This manual refers to the entire range of
MULTITEST family including M72, M73, M74 e M75 models. Except where otherwise
expressly indicated, this manual refers to all these models.
2.1. WORKING
)VHz: DC and AC TRMS voltage measurement, frequency measurement.
)AHz: DC and AC TRMS current measurement, frequency measurement by means
of current transducer (clamp) with max. full scale of 1V.
)Ω: measurement of resistance / continuity with sound signal
): phase sequence detection at one or two terminals
)LAN: wire mapping for cables UTP, STP, FTP (SCTP), SFTP, SSTP in any
category (Cat. 3, 5, 5E, 6, etc.) with connector RJ45 capable of measuring
through connection to remote unit (M75 only).
)Ω0.2A: continuity test on earth, protective and potential equalising conductors with a test
current higher than 200mA and open voltage ranging from 4V to 24V (M72, M74,
M75 only)
)MΩ: insulation resistance measurement with test DC voltage of 250, 500VDC (M72,
M74, M75 only).
)RCD: measurement on RCDs type AC ( )(M73, M74, M75 only)
)Ra measurement of total earth resistance (M73, M74, M75 only)
)AUTO performance of measurements in Ra , RCD and MΩwith automatic sequence (
M74, M75 only)
2.2. TRMS VALUE AND MEAN VALUE - DEFINITIONS
Safety testers for alternate quantities are divided into two categories:
•MEAN VALUE instruments: instruments measuring only the value of the wave at the
fundamental frequency (50 or 60Hz);
•True Root Mean Square (TRMS) instruments: instruments measuring the true root
mean square value of the quantity under test.
Mean value instruments provide only the value of the fundamental wave while TRMS
instruments provide the value of the entire wave, including harmonics (within the passband
of the instrument). Accordingly, the measured values are identical only if the wave is
purely sinusoidal.
2.3. TRUE ROOT MEAN SQUARE VALUE AND CREST FACTOR - DEFINITIONS
The current effective value is defined as follows: “In an interval of time equivalent to a
period, an alternate current with effective value having an intensity of 1A, by passing on a
resistor, disperses the same energy which would be dispersed in the same period of time
by a direct current having an intensity of 1A”. From this definition we get the numerical
expression: G= ∫
+Tt
t
dttg
T
0
0
)(
12The effective value is indicated as RMS (root mean square).
The crest factor is defined as the ratio between the peak value of a signal and its effective
value: CF (G)=
RMS
p
G
G. This value varies according to the waveform of the signal, for a purely
sinusoidal wave it’s worth 2=1.41. In presence of distortions, the higher the wave
distortion is, the higher the crest factor values get.

MULTITEST M72 - M73 - M74 - M75
EN - 5
3. PREPARATION FOR USE
3.1. PRELIMINARY CHECKS
This instrument was checked both mechanically and electrically prior to shipment. All
possible cares and precautions were taken to let you receive the instrument in perfect
conditions. Notwithstanding we suggest you to check it rapidly (eventual damages may
have occurred during transport – if so please contact the local distributor from whom you
bought the item).
Make sure that all standard accessories mentioned in paragraph 6.3 are included.
Should you have to return back the instrument for any reason please follow the
instructions mentioned in paragraph 7.
3.2. POWER SUPPLY
The instrument is powered by batteries (refer to paragraph 6.1.3 for details on model, no.
and battery life). When batteries are low, a low battery indication is displayed.
To replace/insert batteries follow the instructions indicated in paragraph 5.2.
3.3. CALIBRATION
The instrument complies with the technical specifications contained in this manual and
such compliance is guaranteed for 1 year. Annual recalibration is recommended.
3.4. STORAGE
After a period of storage in extreme environmental conditions exceeding the limits
mentioned in paragraph 6.2.1 let the instrument resume normal measuring conditions
before using it.

MULTITEST M72 - M73 - M74 - M75
EN - 6
4. OPERATING INSTRUCTIONS
4.1. INSTRUMENT - DESCRIPTION
LEGEND:
1. Inputs
2. Display
3. ON/OFF key
4. MODE PEAK key
5. Arrows key
6. FUNC HOLD key
7. GO key
8. Remote units for LAN tests
(M75 only)
Fig. 1: Instrument description
to switch on/off the instrument
MODE
PEAK
MODE key to select working mode
PEAK key to select peak measurement
FUNC
HOLD
FUNC key to select working mode
HOLD key to stop display updating
GO
to start a measurement
Arrow keys to select measurements

MULTITEST M72 - M73 - M74 - M75
EN - 7
4.1.1. Turning on
When the instrument is turned on, it emits a brief sound and all
display segments are lit for just one second. Then the model
number and the firmware release appear on the display (see
picture referred to M75). Finally the instrument is ready for
operation.
4.1.2. Auto Power Off
The instrument automatically turns off 10 minutes after last pressure of keys. To resume
operation turn on the instrument again. When the instrument must be used for long
periods, the operator may need to disable the Auto Power Off function. In order to do so:
keep pressed the FUNC HOLD key and turn on the instrument; this way the Auto Power
Off function is deactivated. On next switch on autopower off will be automatically restored.
On the instrument’s LCD the symbol is displayed only when auto power off is active.
4.1.3. Current measurement through external transducer
The instrument measures current through a clamp transducer to be connected to the input
terminals. Unlike traditional multimeters it’s therefore not necessary to interrupt the current
circuit to insert the measuring device. Besides it’s possible to use more clamps having
different full scales according to the current to be measured from time to time. To set the
full scale of the clamp being used, turn on the instrument by keeping pressed MODE
PEAK: the instrument displays the value of the set full scale. To modify such value press
the arrow keys to select the desided full scale, then press MODE PEAK to validate the
modification.
The instrument is supplied with full scale already pre-set for the provided clamp.
4.1.4. Phase sequence and phase conformity measurement
Additional functions (patented) distinguishing this instrument from other multimeters
available on the market are phase sequence and phase conformity measurements
(indispensable to interconnect two three-phase triads) with one test probe.
The instrument performs tests by simply touching the cable under test with the built in test
probe. Note! The instrument performs test by only touching the conductors under voltage
with the single test probe, therefore without having to connect both test probes. The
traditional 2-terminal measurement is however available.

MULTITEST M72 - M73 - M74 - M75
EN - 8
4.2. HOLD, MAX/MIN/AVG, PEAK±
The following functions are available for measurements of AC and DC voltage, AC current,
frequency and resistance.
4.2.1. HOLD
The HOLD function permits to block on the display the detected value during
measurements of AC and DC voltage, AC current, frequency and resistance. Just press
FUNC HOLD for at least one second. The symbol HOLD is displayed. To escape this
function press again FUNC HOLD or the arrow keys.
This function is not available when MAX/MIN/AVG or PEAK± functions are active.
4.2.2. MAX/MIN/AVG
During measurements of AC and DC voltage, AC current, frequency and resistance it’s
possibile to measure and display the maximum (MAX), minimum (MIN) and average
(AVG) valus of the quantity under test. Press FUNC HOLD for more than one second to
enter this function and press it repeatidly for less than one second to run through MAX,
MIN or AVG. The corresponding symbol is displayed.
Maximum, minimum and average values are detected since this function is activated and
are continuously updated even if not displayed. For example, while the AC current average
value is displayed, the maximum and minimum values of the same quantity are
continuously updated.
To escape the MAX/MIN/AVG function press again FUNC HOLD for more than one
second or the arrow keys.
The MAX/MIN/AVG function is not available when HOLD or PEAK± functions are active.
4.2.3. PEAK±
During measurements of AC and DC voltage and AC current it’s possibile to measure and
display the maximum (PEAK+) and minimum (PEAK-) peak values of the quantity under
test with a resolution of 1ms. Press MODE PEAK for more than one second to enter this
function and press it repeatidly for less than one second to run through PEAK+ or PEAK-.
The corresponding symbol is displayed.
Maximum and minimum peak values are detected since this function is activated and are
continuously updated even if not displayed. For example, while the maximum peak values
of AC current is displayed, the minimum peak value of the same quantity is continuously
updated.
When displaying maximum and minimum peaks it’s not mentioned whether the
corresponding quantity is AC or DC: a peak value is absolutely a peak value, regardless of
the quantity at which it’s detected.
To escape this function press again MODE PEAK for more than one second or the arrow
keys.
The HOLD and MAX/MIN/AVG functions are not available when when PEAK± is active.

MULTITEST M72 - M73 - M74 - M75
EN - 9
4.3. V Hz: DC/AC VOLTAGE AND FREQUENCY MEASUREMENT (M73 AND M75)
CAUTION
The maximum input voltage is 550+10%V. Don’t try to measure higher
voltages to avoid risks of electrical shocks or serious damages to the
instrument.
Fig. 2: Connection of the instrument’s terminals during V Hz test
1. Turn on the instrument
2. Press the arrow keys to select VHz
3. Insert the black and green cables in the corresponding input terminals of the
instrument
4. If necessary, insert the croco clips on the test probes
5. Connect the cables to the desired points of the circuit under test as shown in Fig. 2. The
voltage and frequency values will be displayed with automatic range selection.
6. The instrument automatically switches from AC to DC voltage basing on the signal applied
to terminals.
7. AC voltage value Example of display of AC voltage and
frequency values. The minimum reading
limit of AC voltage is 0.5V. Lower input
values are displayed as 0.0V.
Frequency value

MULTITEST M72 - M73 - M74 - M75
EN - 10
8. DC voltage value Example of display of DC voltage. The
minimum reading limit of DC voltage is
1.2V. Lower input values are displayed
as 0.0V.
9.
MODE
PEAK
Press MODE PEAK for less than 1 second to pass to frequency
measurement (only during AC measurements, see paragraph 4.3.1)
10.
MODE
PEAK
Press MODE PEAK for more than 1 second to detect the voltage peak value
(see paragraph 4.2.3)
11.
FUNC
HOLD
Press FUNC HOLD for less than 1 second to block the detected values on the
display (see paragraph 4.2.1)
12.
FUNC
HOLD
Press FUNC HOLD for more than 1 second to detect maximum, minimum
and average voltage values (see paragraph 4.2.2)
4.3.1. Frequency measurement
1. In order to detect minimum, average, maximum and peak values of frequency it's
necessary to pass to this measuring parameter.
2.
MODE
PEAK
During AC measurements it’s possible to pass to frequency measurement by
pressing MODE PEAK for less than 1 second
3. Frequency value Example of display of frequency value.
The minimum reading limit of frequency
is 30.0Hz. Lower input values are
displayed as <30.0Hz
4.
MODE
PEAK
To resume voltage measurement press MODE PEAK for less than 1 second
5.
MODE
PEAK
To detect the frequency peak value press MODE PEAK for more than 1
second (see paragraph 4.2.3)
6.
FUNC
HOLD
To block the detected frequency value on the display press FUNC HOLD for
less than 1 second (see paragraph 4.2.1)
7.
FUNC
HOLD
To detect maximum, minimum and average frequency values press FUNC
HOLD for more than 1 second (see paragraph 4.2.2)

MULTITEST M72 - M73 - M74 - M75
EN - 11
4.3.2. Anomalous cases which may occur during V Hz measurements
1. The maximum input voltage is
550+10%V.
If the detected voltage value exceeds
605V TRMS the instrument displays the
screen beside.
Disconnect immediately the instrument
from the circuit under test to avoid
electrical shocks and damages to the
instrument.
2. If during a voltage measurement the
detected frequency value exceeds 400Hz
the instrument displays the screen
beside.
3. If during a frequency measurement the
detected value exceeds 400Hz the
instrument displays the screen beside.
4. If during a frequency measurement the
detected value does not reach 30.0Hz
the instrument displays the screen
beside.

MULTITEST M72 - M73 - M74 - M75
EN - 12
4.4. A Hz: DC/AC CURRENT AND FREQUENCY MEASUREMENT
Fig. 3: Connection of the instrument’s terminals during A Hz test
1. Turn on the instrument
2. Press the arrow keys to select AHz
3. Insert the banana connectors of the clamp transducer in the corresponding input
terminals of the instrument (black with black, green or red with green)
4. Make sure that the clamp full scale and the instrument full scale do correspond. If they
do not, the measured value will be wrong. To set the clamp full scale refer to
paragraph 4.1.3
5. Open the jaws and insert the cable in the very middle as shown in Fig. 3. Current and
frequency values will be displayed.
6. The instrument automatically switches from AC to DC current basing on the signal applied
to terminals.
7. DC current value Example of DC current displaying. The
minimum limit of DC current is:
1.0mV x transduction ratio of the clamp
lower values are nullified.

MULTITEST M72 - M73 - M74 - M75
EN - 13
8. AC current value Example of AC current displaying. The
minimum limit of AC current is:
1.0mV x transduction ratio of the clamp
lower values are nullified.
Frequency value
The minimum reading value of AC and DC current is given by the herewith:
1mV x transduction ratio of the clamp
Therefore, with a clamp 400A/400mV, the minimum measurable current is 1.0A.
Lower input values are displayed as 0.0A
9.
MODE
PEAK
To pass to frequency measurement press MODE PEAK for less than 1
second (only during AC current measurements, see paragraph 4.4.1)
10.
MODE
PEAK
To detect the current peak value press MODE PEAK for more than 1 second
(see paragraph 4.2.3)
11.
FUNC
HOLD
To block the detected values on the display press FUNC HOLD for less than
1 second (see paragraph 4.2.1)
12.
FUNC
HOLD
To detect maximum, minimum and average current values press FUNC
HOLD for more than 1 second (see paragraph 4.2.2)
4.4.1. Frequency measurement
1. In order to detect minimum, average, maximum and peak values of frequency it's
necessary to pass to this measuring parameter.
2.
MODE
PEAK
It’s possible to pass to frequency measurement by pressing MODE PEAK for
less than 1 second
3. Frequency value Example of display of frequency value.
The minimum reading limit of frequency
is 30.0Hz. Lower input values are
displayed as <30.0Hz.
4.
MODE
PEAK
To resume voltage measurement press MODE PEAK for less than 1 second
5.
MODE
PEAK
To detect the frequency peak value press MODE PEAK for more than 1
second (see paragraph 4.2.3)
6.
FUNC
HOLD
To block the detected frequency value on the display press FUNC HOLD for
less than 1 second (see paragraph 4.2.1)
7.
FUNC
HOLD
To detect maximum, minimum and average frequency values press FUNC
HOLD for more than 1 second (see paragraph 4.2.2)

MULTITEST M72 - M73 - M74 - M75
EN - 14
4.4.2. Anomalous cases which may occur during A Hz measurements
1. Example of clamp full
scale set at 400A AC
If the detected current value exceeds the
clamp full scale the instrument displays
the screen beside.
Disconnect immediately the clamp from
the circuit under test to avoid electrical
shocks and damages to the instrument
The instrument is 20% overchargeable
than the clamp full scale
2. If during a current measurement the
detected frequency value exceeds 400Hz
the instrument displays the screen beside
3. If during a frequency measurement the
detected value exceeds 400Hz the
instrument displays the screen beside
4. If during a frequency measurement the
detected value does not reach 30.0Hz
the instrument displays the screen beside

MULTITEST M72 - M73 - M74 - M75
EN - 15
4.5. Ω: RESISTANCE MEASUREMENT AND CONTINUITY TEST
CAUTION
Before taking resistance measurements make sure that the circuit under test is
not powered and that eventual condensers are discharged.
Fig. 4: Connection of the instrument’s terminals during Ωtest
1. Turn on the instrument
2. Press the arrow keys to select Ω
3. If the measuring cables being used have not been calibrated, first calibrate them as
described in paragraph 4.5.1
Resistance value
4. Insert the black and green cables in the
corresponding input terminals of the
instrument
5. Position the test probes on the desired
points of the circuit under test (see Fig. 4)
6. Example of display of resistance value. If
such value is lower than 40Ωthe
instrument emits an acoustic signal
7.
FUNC
HOLD
To block the detected value on the display press FUNC HOLD for less than 1
second (see paragraph 4.2.1)
8.
FUNC
HOLD
To detect maximum, minimum and average values press FUNC HOLD for
more than 1 second (see paragraph 4.2.2)
9. The measured value is out of accuracy if an input voltage is present
4.5.1. "CAL" mode
1. Any addition or replacement of cables, extensions and croco clips nullify the previous
calibration and make necessary a new calibration before performing further
measurements. Therefore the instrument must be calibrated in the same conditions at
which it will operate during measurements
2. Short-circuit the cable ends with each other as shown in Fig. 5 making sure that the
metallic parts of test probes and crocodiles are in good touch

MULTITEST M72 - M73 - M74 - M75
EN - 16
Fig. 5: Connection of the instrument’s terminals during calibration procedure
3.
MODE
PEAK
Press MODE PEAK for more than 1 second. The instrument resets the
resistance of the cables, the symbol "CAL" is displayed
CAUTION
While MODE PEAK is pressed the instrument is measuring. During this phase
never disconnect test leads.
4. The instrument performs the calibration of cables with resistance lower than 5Ω.
5. At the end of the test the measured value is stored by the instrument and used as
OFFSET, which means it’s deducted from all continuity tests performed) for all further
measurements until a new calibration is made
6. If the value measured during the calibration phase is higher than 5Ωthe instrument
interruptus the calibration, removes the offset value previously stored and does not
display the CAL symbol until the next positive calibration.
This method can be used to nullify the last calibration performed
7. Each time the instrument is switched off the calibrated value is lost
4.5.2. Anomalous cases which may occur during Ωmeasurement
1. The full scale of the instrument is
39.99kΩ.
If the resistance value is higher than this
value, or in case of open or interrupted
probes, the instrument displays the screen
beside.

MULTITEST M72 - M73 - M74 - M75
EN - 17
4.6. : PHASE SEQUENCE AND CONFORMITY MEASUREMENT
CAUTION
The maximum input voltage is 550+10%V. Don’t try to measure higher
voltages to avoid risks of electrical shocks or serious damages to the
instrument. Do not use the instrument on plants whose interlinked rated
voltage is higher than 550V.
Fig. 6: Connection of the instrument’s terminals during test
1. Turn on the instrument
2. Press the arrow keys to select
3.
MODE
PEAK
Press MODE PEAK to select function 1W (1-terminal measurement) or 2W (2-
terminal measurement)
CAUTION
Mode 1W requires the operator to touch the measuring key (without gloves)
and be at the earth potential, and the star centre of the system under test to be
at the earth potential. Only if these conditions are met mode 1W provides
correct results. In absence of just one of the above mentioned conditions
(operator wearing protective gloves or mounting a ladder, IT systems etc.)
select mode 2W.
4. Insert the black wire in the corresponding input terminal of the instrument. If necessary
install the croco-clip on the test probe
5. If mode 2W has been selected, insert the green wire in the corresponding input
terminal of the instrument and connect the test probe to the neutral wire or to the
neutral wire of the plant under test. If necessary install the croco-clip on the test probe
6. Following messages are displayed:
"MEASURING…" the instrument is ready to measure the first phase voltage
"PH1" (secondary display): the operator is invited to connect the measuring cable to the
cable of the first phase voltage

MULTITEST M72 - M73 - M74 - M75
EN - 18
CAUTION
For a correct functioning of mode 1W it’s necessary that the star centre of the
three-phase triad under test is at the earth potential.
In plants with insulated neutral wire, like IT systems (often present in hospitals,
airports etc.) it’s necessary to select mode 2W and connect the green probe to
the neutral conductor (not to the protective conductor). In this kind of plants
mode 1W may not provide correct results.
7.
GO
Only for mode 1W press and keep pressed GO, or simply touch the surface of
the key for the entire duration of the measurement. Connect the test probe to
the first wire of the three-phase triad to be tested
8. When a higher voltage than 110V is detected, the symbol "PH" is displayed and the
buzzer emits a prolonged sound
CAUTION
During measurement:
•GO must be always kept pressed or at least its surface must be always
touched (only for mode 1W)
•the test probe, except for the phase cable under test, must not be in touch
or close to any voltage source which may block the measurement due to
the instrument’s sensitivity
•the test probe must be kept in touch with the phase cable
9. At the end of the measurement the wordings "MEASURING…" and "PH1" disappear.
The buzzer emits and intermitting sound until the test probe is disconnected drom the
phase cable
10. Disconnect the test probe from the cable of the first phase voltage. The wording "PH"
(present only when the input voltage is detected) disappears from the display
11.
GO
Only for mode 1W keep pressed GO, or simply touch its surface, for the entire
duration of the measurement. An eventual release and new pressure on the
key cancels all performed measurements. In this case repeat all previous
passages starting from point 6
12. Following messages are displayed:
"MEASURING…" the instrument is ready to measure the second phase voltage
"PH2" (secondary display): the operator is invited to connect the measuring cable to
the cable of the second phase voltage
CAUTION
If more than 10 seconds pass between the first and the second measurement,
a message "t.out" is displayed. In this case it’s necessary to repeat the entire
procedure. Press GO and re-start from point 6.
13.
GO
Only for mode 1W keep pressed GO, or simply touch its surface, for the entire
duration of the measurement. Connect the test probe to the second cable of
the three-phase triad to be tested
14. When a higher voltage than 110V is detected, the symbol "PH" is displayed and the
buzzer emits a prolonged sound

MULTITEST M72 - M73 - M74 - M75
EN - 19
CAUTION
During measurement:
•GO must be always kept pressed or its surface must be always touched
(only for mode 1W)
•the test probe, except for the phase cable under test, must not be in touch
or close to any voltage source which may block the measurement due to
the instrument’s sensitivity
•the test probe must be kept in touch with the phase cable
15. Correct phase
sequence
A
t the end of the test, if two tested
cables are in a correct phase sequenze,
the instrument emits a double sound to
signal the positive outcome of the test
and displays a screen like this
Phase rotation
16. Cables belonging to
the same phase
A
t the end of the test, if two cables
belong to the same phase, the
instrument emits a double sound to
sigla the positive outcome of the test
and displays a screen like this
Compliance between
one cable and
another
17. Wrong phase
sequence
A
t the end of the test, if two tested
cables are not in the correct phase
sequenze, the instrument emits a
prolonged sound to signal the negative
outcome of the test and displays a
screen like this
Phase rotation
18. To perform a new measurement press GO, then re-start from point 6
CAUTION
A
lthough two cables are in sequence it doesn’t mean that the third cable is in
sequence too. It’s not excluded that the cabling was made by mistake with a
double phase cable. To clear any possible doubt always perform at least two
measurements by testing the cables two by two.