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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 

)

 

V

 

Hz

:   DC and AC TRMS voltage measurement, frequency measurement. 

)

 

A

 

Hz

:   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). 

)

 

Ω

 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 only) 

)

 

M

Ω

:  

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  

M

Ω

 with 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=

+

T

t

t

dt

t

g

T

0

0

)

(

1

2

 The 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. 

Summary of Contents for MULTITEST M72

Page 1: ... Copyright HT ITALIA 2006 Release EN 2 00 22 08 2006 ENGLISH User s manual ...

Page 2: ...15 4 5 2 Anomalous cases which may occur during Ω measurement 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 Ω 0 2A Continuity test on earth protective and equalizing potential conductors M...

Page 3: ...aces 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 b...

Page 4: ... 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 measuremen...

Page 5: ...nce M73 M74 M75 only AUTO performance of measurements in Ra RCD and MΩ with 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 t...

Page 6: ... 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...

Page 7: ...ows 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 ...

Page 8: ...al 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 ...

Page 9: ... 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 maxim...

Page 10: ...e 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 ...

Page 11: ...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 ar...

Page 12: ... 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...

Page 13: ...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 te...

Page 14: ...raph 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 Frequ...

Page 15: ...ircuit 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 measureme...

Page 16: ...mple of display of resistance value If such value is lower than 40Ω the 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...

Page 17: ...ch 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 5Ω the 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 calibra...

Page 18: ... 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...

Page 19: ...e 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 surfac...

Page 20: ...ging to the same phase At 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 At 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 negat...

Page 21: ...ire procedure Press GO and re start from point 6 2 If mode 1W is selected and the instrument detects the connection of the second probe like in mode 2W a screen like this is displayed to signal the error A prolonged sound is emitted until the error condition is removed 3 If mode 2W is selected and the instrument detects an input voltage between the two bushes higher than 605V a screen like this is...

Page 22: ...ll shielded cables such as FTP Foiled Twisted Pair cable SSTP Shielded Shielded Twisted Pair cable STP Shielded Twisted Pair cable SFTP Shielded Foiled Twisted Pair cable 4 Connect the cable under test to MULTITEST 75 and to the remote unit if necessary through patch cables see Fig 7 CAUTION The remote unit must be necessarily connected to the other end of the cable being tested otherwise no measu...

Page 23: ...lous cases which may occur during LAN tests If the voltage present at the terminal is higher 0 2V the instrument does not perform the test and emits a sound to signal the anomalous situation The screen beside is displayed CAUTION Before taking any measurement make sure that the circuit under test is not powered Connections to phone lines or active networks could damage the instrument 4 7 2 SPLIT P...

Page 24: ...4 3 5 6 S 8 7 SHORTED CABLES Two conductors are in short circuit between each other 1 2 4 3 5 6 S 8 7 1 2 4 3 5 6 S 8 7 TRANSPOSED CROSSED PAIRS Two pairs are crossed 1 2 4 3 5 6 S 8 7 1 2 4 3 5 6 S 8 7 MISWIRE Generic cabling error such as for example two conductors belonging to different pairs are exchanged 1 2 4 3 5 6 S 8 7 1 2 4 3 5 6 S 8 7 SPLIT PAIRS The pin to pin correspondence is hold but...

Page 25: ...ection of the instrument s terminals during Ω 0 2A test 1 Turn on the instrument 2 Press the arrow keys to select Ω 0 2A 3 Insert the black and green cables in the corresponding input terminals of the instrument 4 If the cable length is not sufficient to perform the test extend the black one 5 If necessary insert the croco clips on the test probes 6 If the measuring cables being used have not been...

Page 26: ...er resistance values the instrument performs the test with decreasing current 10 Resistance value At the end of the test if it has been possible to generate at least 200mA not particularly high resistance value the instrument emits a double sound to signal the positive outcome of the test The screen beside is displayed Test current value 11 Resistance value At the end of the test if it has not bee...

Page 27: ...ng any further measurement even in case the instrument is turned off and on 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 The instrument emits a double sound to signal the positive outcome of the calibration procedure and displays a s...

Page 28: ... higher than 10V the instrument does not perform the test and emits a prolonged sound to signal the anomalous situation The screen beside is displayed for 5 seconds after which the instrument displays the default value related to the Ω 0 2A test Input voltage 3 If the resistance value is higher than the full scale the instrument emits a prolonged sound to signal the anomalous situation A screen si...

Page 29: ...ted In case of doubt bifore performing an insulation test perform a Ω 0 2A measurement by short circuiting the cables under test at a point of the plant which is as far as possibile from the measuring clips Remove the short circuit before performing the insulation test Fig 10 Connection of the instrument s terminals during MΩ test 1 Turn on the instrument 2 Press the arrow keys to select MΩ Select...

Page 30: ...alue is higher than 999MΩ so higher than the full scale the instrument emits a double sound to signal the positive outcome of the test A screen similar to this is displayed Note An insulation value higher than 999MΩ is an excellent insulation value generally much higher than the minimum requirements prescribed by Standards 12 Resistance value At the end of the test if the resistance value is lower...

Page 31: ...ing MODE select the test current among the possible values 30mA 30mA x5 100mA 300mA which turn cyclically at each key pressure CAUTION Pay attention when setting the test current of the RCD to make sure that the correct one is selected In case a higher current than the nominal one of the device under test is selected the RCD would be tested at a higher current than the correct one thus favouring a...

Page 32: ...he instrument emits a double sound to signal the positive outcome of the test and displays a screen like this Test current value 8 Tripping time exceeding the limit At the end of the test if the detected tripping time is higher than 300ms 40ms for I n 30mA x5 or in case the RCD does not trip the instrument emits a prolonged sound to signal the negative outcome of the test and displays a screen lik...

Page 33: ...nt does not perform the test and emits a prolonged sound to signal the anomalous situation The screen beside is displayed for 5 seconds after which the instrument displays the default screen of RCD test 4 If during measurement an excessive contact voltage is detected higher than 50V the instrument does not perform the test and emits a prolonged sound to signal the anomalous situation The screen be...

Page 34: ...cally at each key pressure CAUTION If a RCD is present select a lower current value than the nominal current value of the device Otherwise the RCD could trip during the measurement and therefore prevent it from being executed By selecting a test current of 100mA you will get also the value of the prospective short circuit current phase to earth calculated according to the formula ICC PE N Z U wher...

Page 35: ...rement 9 Measured value of global earth resistance The symbol HOLD remains on until a new measurement can be taken If a test current of 100mA has been selected and the earth resistance value is lower than 1999Ω by pressing FUNC you will display alternatively the values of the global earth resistance and the prospective short circuit current phase to earth as well as the current at which the measur...

Page 36: ...d for 5 seconds after which the instrument displays the default screen of Ra test 3 If during measurement a lower input voltage than 110V is detected the instrument does not perform the test and emits a prolonged sound to signal the anomalous situation The screen beside is displayed for 5 seconds after which the instrument displays the default screen of Ra test This can happen for example if the b...

Page 37: ...ed to the protective conductor the instrument does not perform the test and emits a prolonged sound to signal the anomalous situation The screen beside is displayed for 5 seconds after which the instrument displays the default screen of Ra test This can happen even if the wrong connection is performed on the back side of the power socket ...

Page 38: ...he test current among the possible values 30mA 30mA x5 100mA 300mA which turn cyclically at each key pressure CAUTION Pay attention when setting the test current of the RCD to make sure that the correct one is selected In case a higher current than the nominal one of the device under test is selected the RCD would be tested at a higher current than the correct one thus favouring a quicker tripping...

Page 39: ...time is lower than the maximum admittable limit the instrument displays for 5 seconds a screen like this then it passes to the following screen For further details or information regarding the negative outcome of the test or anomalous situations refer to paragraph 4 10 Value of test current 10 Measured value of resistance At the end of the MΩ test if the detected resistance value is higher than 0 ...

Page 40: ...m the input terminals to avoid electrical shocks 1 Switch off the instrument 2 Remove test leads from the input terminals 3 Remove the battery compartment cover by using a screwdriver 4 Remove all batteries replacing them with new ones all of the same type refer to paragraph 6 1 3 respecting the polarity signs 5 Re allocate the battery pack taking care that the part from which the black and red wi...

Page 41: ...Hz Accuracy 70 400Hz Input impedance Overload protection 1 0 999 9mV 0 1mV 1 000 1 200V 0 001V 0 5 rdg 2 dgt 1 0 rdg 2 dgt 2 0 rdg 2 dgt 1MΩ 605V AC max RMS The mentioned accuracy does not consider the transducer s accuracy Please refer to its user s manual MAX MIN AVG PEAK resolution 5 0 rdg 10 dgt responce time 500ms MAX MIN AVG 1ms PEAK Minimum input current 1mV x transduction ratio of the clam...

Page 42: ...ange Open circuit voltage 1 3 x V0 Accuracy of nominal voltage 0 10 Short circuit current 3 0mA Nominal testing current 1mA 1KΩ x V 1mA 500KΩ RCD test on RCD devices AC type M73 M74 M75 Range Resolution Accuracy Overload protection 2 400ms 1ms 2 0 rdg 2 dgt 605V max RMS Phase to ground voltage 110 265V Test currents 30mA 30mA x 5 100mA 300mA Frequency 50Hz 0 5Hz 60Hz 0 5Hz Ra Measurement of global...

Page 43: ...r supply Battery type 4 batteries 1 5 V LR6 AA AM3 MN 1500 Low battery indication the symbol is displayed when the battery voltage is too low Battery life Multimeter About 90 hours 1000 tests LAN 1000 tests Ω 0 2A 1000 tests 1Ω MΩ 1000 tests 480kΩ 500VDC RCD 1000 tests Ra 1000 tests AUTO 1000 tests Display Features 4 LCD with max reading 9999 counts symbol and decimal point 6 2 ENVIRONMENT 6 2 1 E...

Page 44: ... in transit Repairs made necessary by previous attempts for repair carried out by non skilled or unauthorized personnel Instruments for whatever reason modified by the customer himself without explicit authorization of our Technical Dept The contents of this manual may not be reproduced in any form whatsoever without the manufacturer s authorization Our products are patented and our logotypes regi...

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