HT instruments М75 User Manual
M72 – M73 – M 74 – M75
User manual
Copyright HT ITALIA 2013 Release EN 3.00 - 03/04/2013
M72 - M73 - M74 - M75
Table of contents
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. Features ........................................................................................................................................... 4
2.2. TRMS value and mean value - Definitions ....................................................................................... 4
2.3. True root measn 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
4.2. Switch on the instrument .................................................................................................................. 7
4.3. Disable Auto Power OFF.................................................................................................................. 7
4.4. Modify full scale of external transducers .......................................................................................... 7
4.5. Set minimum limit threshold on insulation measurement ................................................................. 7
4.6. HOLD, MAX/MIN/AVG, PEAK± ........................................................................................................ 8
4.6.1. HOLD ......................................................................................................................................................... 8
4.6.2. MAX/MIN/AVG ........................................................................................................................................... 8
4.6.3. PEAK± ....................................................................................................................................................... 8
4.7. V Hz: DC/AC voltage and frequency measurement .................................................................... 9
4.7.1. Anomalous cases which may occur during V Hz measurements ........................................................... 11
4.8. A Hz: DC/AC current and frequency measurement .................................................................. 12
4.8.1. Anomalous cases which may occur during A Hz measurements .......................................................... 14
4.9. : Resistance measurement and continuity test ....................................................................... 15
4.9.1. "CAL" mode ............................................................................................................................................. 15
4.9.2. Anomalous cases which may occur during measurement .............................................................. 16
4.10. : Phase sequence and phase conformity measurement ............................................................ 17
4.10.1. Anomalous cases which may occur during tests ..................................................................................... 20
4.11. LAN: Cabling test (M75) ................................................................................................................. 21
4.11.1. Anomalous cases which may occur during LAN tests .............................................................................. 22
4.11.2. SPLIT PAIRS - explication note ............................................................................................................... 22
4.11.3. Cabling errors detected by the instrument ............................................................................................... 23
4.12. 0.2A: Continuity test on earth conductors (M72, M74, M75) ....................................................... 24
4.12.1. "CAL" mode ............................................................................................................................................. 25
4.12.2. Anomalous cases which may occur during 0.2A tests ........................................................................... 27
4.13. M: Insulation measure (M72, M74, M75) ..................................................................................... 28
4.13.1. Anomalous cases which may occur during M tests ............................................................................... 29
4.14. RCD: Tests on AC type RCDs (M73, M74, M75) ........................................................................... 30
4.14.1. Anomalous cases which may occur during RCD tests ............................................................................. 31
4.15. Ra : Measurement of global earth resistance (M73, M74, M75) ................................................ 33
4.15.1. Anomalous cases which may occur during Ra tests ............................................................................ 35
4.16. AUTO: Automatic cycle of measurements (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. Reference guidelines ...................................................................................................................... 42
6.2. General specifications .................................................................................................................... 42
6.3. Environment ................................................................................................................................... 42
6.3.1. Environmental conditions ......................................................................................................................... 42
6.4. Accessories .................................................................................................................................... 42
7. SERVICE ................................................................................................................................ 43
7.1. Warranty conditions ........................................................................................................................ 43
7.2. After-sale service ............................................................................................................................ 43
EN - 1
M72 - M73 - M74 - M75
1. SAFETY PRECAUTIONS AND PROCEDURES
This instrument complies with safety Standards IEC/EN61557-1 and IEC/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
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:
preceded by this symbol .
CAUTION - refer to the instruction manual - an improper use may damage the
instrument or its components
CAUTION for dangerious voltage. Risk of electric shock
DC or AC voltage or current
Meter with double insulation
Ground reference
The symbol indicates that the instrument shall not be connected to systems with
rated line voltage (Phase to Phase) higher than 605V.
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 CAT III 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
EN - 2
M72 - M73 - M74 - M75
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 § 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 IEC/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 § 6.7.4: Measuring circuits it says:
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.
EN - 3
M72 - M73 - M74 - M75
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. FEATURES
V Hz: DC and AC TRMS voltage measurement, frequency measurement.
A
: measurement of resistance / continuity with sound signal
Hz: DC and AC TRMS current measurement, frequency measurement by means
of current transducer (clamp) with max. full scale of 1V.
: phase sequence detection at one or two terminals
LAN: wire mapping for cables UTP/STP in any category with connector RJ45
capable of measuring through connection to remote unit (M75).
0.2A: 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)
M: insulation resistance measurement with test DC voltage of 250, 500VDC
(M72, M74, M75)
RCD: measurement on RCDs type AC (
)(M73, M74, M75)
Ra measurement of total earth resistance (M73, M74, M75)
AUTO performance of measurements in Ra , RCD and M with automatic
sequence ( M74, M75)
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 MEASN 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
Tt
expression: G=
0
1
T
The effective value is indicated as RMS (root mean square).
2
dttg
)(
t
0
The crest factor is defined as the ratio between the peak value of a signal and its effective
G
p
value: CF (G)=
sinusoidal wave it’s worth
. This value varies according to the waveform of the signal, for a purely
G
RMS
2 =1.41. In presence of distortions, the higher the wave
distortion is, the higher the crest factor values get.
EN - 4
M72 - M73 - M74 - M75
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 § 6.4 are included.
Should you have to return back the instrument for any reason please follow the
instructions mentioned in § 7.
3.2. POWER SUPPLY
The instrument is powered by 4x1.5V batteries type AA LR6. When batteries are low, a
low battery indication " " is displayed. To replace/insert batteries follow the instructions
indicated in § 5.2.
3.3. CALIBRATION
The instrument complies with the technical specifications contained in this manual and
such compliance is guaranteed for 12 months. Annual recalibration is recommended.
3.4. STORAGE
After a period of storage in extreme environmental conditions exceeding the limits
mentioned in § 6.3.1 let the instrument resume normal measuring conditions before using
it.
EN - 5
M72 - M73 - M74 - M75
A
4. OPERATING INSTRUCTIONS
4.1. INSTRUMENT DESCRIPTION
CAPTION:
1. Inputs
2. LCD 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)
Fig. 1: Instrument description
CAPTION:
1. Input terminal B2
2. Input terminal B1
3. Sliding cover for RJ45
connectors of LAN networks
(M75)
Fig. 2: Instrument inputs description
GO key to start a
GO
measurement
rrow keys to select
measurements
MODE
PEAK
FUNC
HOLD
ON/OFF key To switch on/off the
instrument
MODE/PEAK key to select working mode
and to select peak measurement
FUNC/HOLD key to select internal
functions and to stop display updating
Table 1: Instrument function keys description
EN - 6
M72 - M73 - M74 - M75
4.2. SWITCH ON THE INSTRUMENT
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.
4.3. DISABLE 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:
1. Keep pressed the FUNC/HOLD key while turn on the instrument with the ON/OFF key.
The symbol “ ” disappear at display
2. On next switch on auto power off will be automatically restored and the symbol “ ”
appear at display
4.4. MODIFY FULL SCALE OF EXTERNAL TRANSDUCERS
The instrument measures AC/DC 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 follow the herewith steps:
1. Keep pressed the MODE/PEAK key while turn on the instrument with the ON/OFF key.
The instrument displays the “SET” message and the value of the set full scale
2. Press the arrow keys to select the desided full scale (the possible values are 1, 10, 20,
30, 100, 200, 300, 400, 1000, 2000, 3000A)
3. Press MODE/PEAK key twice to validate the modification
4.5. SET MINIMUM LIMIT THRESHOLD ON INSULATION MEASUREMENT
To set the minimum limit threshold recognized by the instrument in the insulation
measurement (see § 4.13) follow the herewith steps:
1. Keep pressed the MODE/PEAK key while turn on the instrument with the ON/OFF key.
The instrument displays the “SET” message and the value of the set full scale
2. Press the arrow keys to select the desired value (possible value are 0.25, 0.50,
1.00M)
3. Press MODE/PEAK key to validate the modification
EN - 7
M72 - M73 - M74 - M75
4.6. HOLD, MAX/MIN/AVG, PEAK±
The following functions are available for measurements of AC and DC voltage, AC current,
frequency and resistance.
4.6.1. HOLD
The HOLD function permits to block on the display the detected value during
measurements of AC and DC voltage, AC and DC 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.
4.6.2. MAX/MIN/AVG
During measurements of AC and DC voltage, AC and DC 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.
4.6.3. PEAK±
During measurements of AC and DC voltage and AC/DC 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.
EN - 8
M72 - M73 - M74 - M75
4.7. V HZ: DC/AC VOLTAGE AND FREQUENCY 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.
Fig. 3: Connection of the instrument’s terminals during V Hz test
1. Turn on the instrument
2. Press the arrow keys to select V Hz
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. 3.
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. Example of display of AC voltage and
AC voltage value
frequency values. The minimum reading
limit of AC voltage is 0.5V. Lower input
values are displayed as 0.0V
EN - 9
Frequency value
M72 - M73 - M74 - M75
8. Example of display of DC voltage. The
DC voltage value
minimum reading limit of DC voltage is
1.2V. Lower input values are displayed
as 0.0V
9. Press MODE/PEAK for less than 1 second to pass to frequency measurement (only
during AC measurement)
10. Press MODE/PEAK for more than 1 second to detect the voltage peak value (see §
4.6.3)
11. Press FUNC/HOLD for less than 1 second to block the detected values on the display
(see § 4.6.1)
12. Press FUNC/HOLD for more than 1 second to detect maximum, minimum and
average voltage values (see § 4.6.2)
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. During AC measurements it’s possible to pass to frequency measurement by pressing
MODE/PEAK for less than 1 second
3. Example of display of frequency value.
Frequency value
The minimum reading limit of frequency
is 30.0Hz. Lower input values are
displayed as <30.0Hz
4. To resume voltage measurement press MODE/PEAK for less than 1 second
5. To detect the frequency peak value press MODE/PEAK for more than 1 second (see §
4.6.3)
6. To block the detected frequency value on the display press FUNC/HOLD for less than
1 second (see § 4.6.1)
7. To detect maximum, minimum and average frequency values press FUNC/HOLD for
more than 1 second (see § 4.6.2)
EN - 10
M72 - M73 - M74 - M75
4.7.1. 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
EN - 11
M72 - M73 - M74 - M75
4.8. A HZ: DC/AC CURRENT AND FREQUENCY MEASUREMENT
Fig. 4: Connection of the instrument’s terminals during A Hz test
1. Turn on the instrument
2. Press the arrow keys to select A Hz
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). For
transducers with FRB hypertac connector is necessary the NOCANBA optional
accessory
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 § 4.4
5. Open the jaws and insert the cable in the very middle as shown in Fig. 4. 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. Example of DC current displaying. The
DC current value
minimum limit of DC current is:
1.0mV x transduction ratio of the clamp
lower values are nullified
EN - 12
M72 - M73 - M74 - M75
8. Example of AC current displaying. The
minimum limit of AC current is:
1.0mV x transduction ratio of the clamp
lower values are nullified.
AC current value
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.
To pass to frequency measurement press MODE/PEAK for less than 1 second (only
during AC current measurements)
10. To detect the current peak value press MODE/PEAK for more than 1 second (see §
4.6.3)
11. To block the detected values on the display press FUNC/HOLD for less than 1
second (see § 4.6.1)
12. To detect maximum, minimum and average current values press FUNC/HOLD for
more than 1 second (see § 4.6.2)
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. It’s possible to pass to frequency measurement by pressing MODE/PEAK for less than
1 second
3. Example of display of frequency value.
Frequency value
The minimum reading limit of frequency
is 30.0Hz. Lower input values are
displayed as <30.0Hz
4. To resume voltage measurement press MODE/PEAK for less than 1 second
5. To detect the frequency peak value press MODE/PEAK for more than 1 second (see §
4.6.3)
6. To block the detected frequency value on the display press FUNC/HOLD for less than
1 second (see § 4.6.1)
7. To detect maximum, minimum and average frequency values press FUNC/HOLD for
more than 1 second (see § 4.6.2)
EN - 13
Loading...