HT instruments HT9022 User Manual

ENGLISH

User manual

HT9022

Table of contents:

1. PRECAUTIONS AND SAFETY MEASURES ........................................................................... 3

1.1. Preliminary instructions .................................................................................................................... 4

1.2. During use ........................................................................................................................................ 4

1.3. After use ........................................................................................................................................... 4

1.4. Definition of measurement (overvoltage) category .......................................................................... 5

2. GENERAL DESCRIPTION ....................................................................................................... 6

2.1. Measuring average values and TRMS values ................................................................................. 7

2.2. Definition of true root mean square value and crest factor .............................................................. 7

2.3. Harmonics ........................................................................................................................................ 7

3. PREPARATION FOR USE ....................................................................................................... 8

3.1. Initial checks ..................................................................................................................................... 8

3.2. Instrument power supply .................................................................................................................. 8

3.3. Calibration ........................................................................................................................................ 8

3.4. Storage ............................................................................................................................................. 8

4. OPERATING INSTRUCTIONS ................................................................................................. 9

4.1. Instrument description ...................................................................................................................... 9

4.1.1. Description of the controls ................................................................................................................... 9

4.1.2. Alignment marks.................................................................................................................................. 9

4.1.3. Hand protection ................................................................................................................................. 10

4.1.4. Indication of the conventional direction of Current ............................................................................ 10

4.2. Description of the keys ................................................................................................................... 10

4.2.1. Keys F1 – F2 – F3 – F4 .................................................................................................................... 10

4.2.2. Key H................................................................................................................................................. 10

4.2.3. Key .............................................................................................................................................. 10

4.3. Initial screen ................................................................................................................................... 11

5. INSTRUMENT FUNCTIONS ................................................................................................... 12

5.1. Phase detection .............................................................................................................................. 12

5.2. “Settings” position: Instrument settings .......................................................................................... 12

5.2.1. General.............................................................................................................................................. 12

5.2.2. Date/Time .......................................................................................................................................... 12

5.2.3. Log .................................................................................................................................................... 13

5.2.4. InRush ............................................................................................................................................... 13

5.2.5. Continuity .......................................................................................................................................... 13

5.3. Position “V ”: DC, AC+DC voltage measurement and phase sequence verification ................... 14

5.3.1. DC voltage measurement.................................................................................................................. 14

5.3.1.1. Key F4 “Fnz” .................................................................................................................................... 15

5.3.1.2. Hold ................................................................................................................................................. 15

5.3.1.3. Backlight .......................................................................................................................................... 15

5.3.2. AC+DC voltage and Voltage Harmonics measurement .................................................................... 16

5.3.2.1. Key F2 “Par” .................................................................................................................................... 16

5.3.2.2. AC+DC voltage ................................................................................................................................ 16

5.3.2.2.1. Key F4 “Fnz” in AC+DC voltage measurement ........................................................................... 17

5.3.2.3. Voltage harmonics ........................................................................................................................... 17

5.3.2.3.1. Key F4 “Fnz” in Voltage Harmonics measurement...................................................................... 17

5.3.2.4. Hold ................................................................................................................................................. 18

5.3.2.5. Backlight .......................................................................................................................................... 18

5.3.3. Checking phase sequence and phase concordance with a lead ...................................................... 19

5.3.3.1. Verification of Phase Sequence. ...................................................................................................... 19

5.3.3.2. Verification of Phase Concordance .................................................................................................. 21

5.4. Position “A ”: DC, AC+DC current measurement ........................................................................ 23

5.4.1. DC current measurement .................................................................................................................. 23

5.4.1.1. Key F4 “Fnz” .................................................................................................................................... 24

5.4.1.2. Hold ................................................................................................................................................. 24

5.4.1.3. Backlight .......................................................................................................................................... 24

5.4.2. AC+DC current and Current Harmonics measurement ..................................................................... 25

5.4.2.1. Key F2 “Par” .................................................................................................................................... 25

5.4.2.2. AC+DC current ................................................................................................................................ 25

5.4.2.2.1. Key F4 “Fnz” in AC+DC current measurement ........................................................................... 26

5.4.2.3. Current harmonics ........................................................................................................................... 26

5.4.2.3.1. Key F4 “Fnz” in Current Harmonics measurement ...................................................................... 26

5.4.2.4. Hold ................................................................................................................................................. 27

5.4.2.5. Backlight .......................................................................................................................................... 27

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5.5. Position “W ”: DC, AC+DC power measurement ......................................................................... 28

5.5.1. DC power measurement ................................................................................................................... 29

5.5.1.1. Key F2 “Par” .................................................................................................................................... 29

5.5.1.2. DC power ......................................................................................................................................... 30

5.5.1.2.1. Key F4 “Fnz” in DC Power measurement ................................................................................... 30

5.5.1.3. DC voltage and current .................................................................................................................... 30

5.5.1.3.1. Key F4 “Fnz” in DC Voltage and Current measurement .............................................................. 31

5.5.1.4. DC Energy ....................................................................................................................................... 31

5.5.1.5. Hold ................................................................................................................................................. 31

5.5.1.6. Backlight .......................................................................................................................................... 31

5.5.2. Measurement of AC 1P or AC 3P Powers ........................................................................................ 32

5.5.2.1. Key F2 “Par” .................................................................................................................................... 32

5.5.2.2. AC+DC power .................................................................................................................................. 33

5.5.2.3. Pf and dPf ........................................................................................................................................ 33

5.5.2.3.1. Key F4 “Fnz” in Power or Pf-dPf measurement .......................................................................... 33

5.5.2.4. AC+DC Voltage and Current............................................................................................................ 34

5.5.2.4.1. Key F4 “Fnz” in AC Voltage and Current measurement .............................................................. 34

5.5.2.5. Voltage harmonics ........................................................................................................................... 35

5.5.2.6. Current harmonics ........................................................................................................................... 35

5.5.2.6.1. Key F4 “Fnz” in Voltage and Current Harmonics measurement .................................................. 35

5.5.2.7. AC Energy ....................................................................................................................................... 36

5.5.2.8. Hold ................................................................................................................................................. 36

5.5.2.9. Backlight .......................................................................................................................................... 36

5.6. Position “W ”: Log, On-Line Scope, SnapShot, MemorY, Download .......................................... 37

5.6.1. Key F3 “Sys”...................................................................................................................................... 37

5.6.1.1. “Start Log” recording ........................................................................................................................ 37

5.6.1.2. On-line ............................................................................................................................................. 38

5.6.1.3. Memory ............................................................................................................................................ 39

5.6.1.4. SnapShot ......................................................................................................................................... 39

5.6.1.5. Download ......................................................................................................................................... 40

5.7. Position “Ω ”: Resistance and continuity measurement .............................................................. 41

5.7.1. Key F4 “Fnz”...................................................................................................................................... 42

5.7.1.1. Hold ................................................................................................................................................. 42

5.7.1.2. Backlight .......................................................................................................................................... 42

5.8. Position “InRush A ”: inrush current measurement ..................................................................... 43

5.8.1. Virtual key “Zero” ............................................................................................................................... 44

5.8.2. Key F3 “Run” ..................................................................................................................................... 44

5.8.3. Key F4 “Mem”.................................................................................................................................... 44

6. MAINTENANCE ...................................................................................................................... 46

6.1. General information ........................................................................................................................ 46

6.2. Battery replacement ....................................................................................................................... 46

6.3. Cleaning the instrument ................................................................................................................. 46

6.4. End of life ....................................................................................................................................... 46

7. TECHNICAL SPECIFICATIONS ............................................................................................. 47

7.1. Technical characteristics ................................................................................................................ 47

7.1.1. Safety standards ............................................................................................................................... 49

7.1.2. General characteristics...................................................................................................................... 49

7.2. ENVIRONMENT ............................................................................................................................. 49

7.2.1. Environmental conditions for use ...................................................................................................... 49

7.3. Accessories provided ..................................................................................................................... 49

8. SERVICE ................................................................................................................................ 50

8.1. Warranty conditions ........................................................................................................................ 50

8.2. Service ........................................................................................................................................... 50

9. APPENDIX – THEORETICAL OUTLINE ................................................................................ 51

9.1. Calculation of powers in “AC 1P” mode ......................................................................................... 51

9.2. Calculation of powers in “AC 3P” mode ......................................................................................... 51

9.3. Calculation of powers in “DC” mode .............................................................................................. 51

9.4. voltage and current harmonics ....................................................................................................... 52

9.5. Limit values for harmonics ............................................................................................................. 53

9.6. Causes of the presence of harmonics ............................................................................................ 53

9.7. Consequence of the presence of harmonics ................................................................................. 54

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HT9022

1. PRECAUTIONS AND SAFETY MEASURES

The instrument has been designed in compliance with directive IEC/EN61010-1 relevant to electronic measuring instruments. For your safety and in order to prevent damaging the instrument, please carefully follow the procedures described in this manual and read all

notes preceded by the symbol with the utmost attention.

Before and after carrying out the measurements, carefully observe the following instructions:

• Do not carry out any voltage or current measurement in humid environments.

• Do not carry out any measurements in case gas, explosive materials or flammables are

present, or in dusty environments.

• Avoid contact with the circuit being measured if no measurements are being carried

out.

• Avoid contact with exposed metal parts, with unused measuring probes, circuits, etc.

• Do not carry out any measurement in case you find anomalies in the instrument such

as deformation, breaks, substance leaks, absence of display on the screen, etc.

• Pay special attention when measuring voltages higher than 20V, since a risk of

electrical shock exists.

In this manual, and on the instrument, the following symbols are used:

Warning: observe the instructions given in this manual; an improper use could damage the instrument or its components.

High voltage danger: electrical shock hazard.

Double-insulated meter

AC voltage or current

DC voltage or current

Connection to earth

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1.1. PRELIMINARY INSTRUCTIONS

• This clamp has been designed for use in environments of pollution degree 2.

• It can be used for CURRENT and VOLTAGE measurements on installations with

measurement category CAT IV 600V and CAT III 1000V. For a definition of measurement categories, see § 1.4.

• We recommend following the normal safety rules devised by the procedures for

carrying out operations on live systems and using the prescribed PPE to protect the user against dangerous currents and the instrument against incorrect use.

• Only the leads supplied with the instrument guarantee compliance with the safety

standards. They must be in good conditions and replaced with identical models, when necessary.

• In case the lack of warning against the presence of voltage may constitute a danger for

the operator:

1. always carry out a continuity measurement before carrying out the measurement of the live system to confirm the correct connection and condition of the leads;

2. before carrying out the critical measurement, carry out a measurement at a power socket where voltage is surely present. As an alternative, make this verification at your site before going to the unknown measuring point.

• Do not test circuits exceeding the specified current and voltage limits.

• Check that the battery is correctly inserted.

• Before connecting the test leads to the circuit to be tested, make sure that the switch is

correctly set.

• Make sure that the LCD display and the switch indicate the same function.

1.2. DURING USE

Please carefully read the following recommendations and instructions:

WARNING

Failure to comply with the Caution notes and/or Instructions may damage the instrument and/or its components or be a source of danger for the operator.

• Before activating the switch, remove the conductor from the clamp jaw or disconnect

the test leads from the circuit under test.

• When the instrument is connected to the circuit under test, do not touch any unused

terminal.

• Keep your hands always under the hand protection. This protection is always located in

a suitable position to guarantee a correct safety distance from possible exposed or live parts (see Fig. 3: hand protection

• Avoid measuring resistance if external voltages are present. Even if the instrument is

protected, excessive voltage could cause a malfunction of the clamp.

• During current measurement, any other current near the clamp may affect

measurement precision.

• When measuring current, always put the conductor as near as possible to the middle of

the clamp jaw, to obtain the most accurate reading.

• While measuring, if the value or the sign of the quantity being measured remain

unchanged, check if the HOLD function is enabled.

1.3. AFTER USE

• When measurement is complete, switch OFF the instrument.

• If the instrument is not to be used for a long time, remove the batteries.

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HT9022

1.4. DEFINITION OF MEASUREMENT (OVERVOLTAGE) CATEGORY

Standard CEI 61010: Safety requirements for electrical equipment for measurement, control and laboratory use, Part 1: General requirements” defines what measurement category, commonly called overvoltage category, is. In § 6.7.4: Measured circuits, circuits are divided into the following measurement categories:

(OMISSIS)

• 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 on installations inside

buildings.

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 standard requires that the transient withstand capability of the equipment is made known to the user.

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HT9022

2. GENERAL DESCRIPTION

The clamp meter HT9022 carries out the following measurements:

• DC voltage and AC+CD TRMS voltage

• DC current and AC+CD TRMS current

• Phase sequence

• Active, reactive, apparent power and power factor on single-phase and/or balanced

three phase systems

• Active, reactive, apparent energy on single-phase and/or balanced three-phase

systems

• AC voltage harmonics (1st – 25th) and THD% up to 75Hz (1st – 8th above 75Hz)

• AC current harmonics (1st – 25th) and THD% up to 75Hz (1st – 8th above 75Hz)

• DC power

• Frequency on voltage (leads) and current (clamp jaw)

• Resistance and continuity test with buzzer

• Electric motor starting currents (INRUSH)

• Detection of presence of AC voltage with and without contact with in-built sensor in the

clamp jaw

Each of these functions can be selected using the 7-position selector switch, including an OFF position.

Keys F1, F2, F3, F4 e H / are also provided; for their use, please refer to § 4.2.

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2.1. MEASURING AVERAGE VALUES AND TRMS VALUES

Measuring instruments of alternating quantities are divided into two big families:

• AVERAGE-VALUE meters: instruments measuring the value of the sole wave at fundamental frequency from 10 to 400Hz

• TRMS (True Root Mean Square) VALUE meters: instruments measuring the TRMS value of the quantity being tested.

In the presence of a perfectly sinusoidal wave, the two families of instruments provide identical results. In the presence of distorted waves, instead, the readings shall differ. Average-value meters provide the RMS value of the sole fundamental wave, TRSM meters, instead, provide the RMS value of the whole wave, including harmonics (within the instrument’s bandwidth). Therefore, by measuring the same quantity with instruments from both families, the values obtained are identical only if the wave is perfectly sinusoidal. In case it is distorted, TRMS meters shall provide higher values than the values read by average-value meters.

2.2. DEFINITION OF TRUE ROOT MEAN SQUARE VALUE AND CREST FACTOR

The root mean square value of current is defined as follows: "In a time equal to a period, an alternating current with a root mean square value of the intensity of 1A, circulating on a resistor, dissipates the same energy that, during the same time, would have been dissipated by a direct current with the intensity of 1A". This definition results in the numeric

expression:

+Tt

∫

dttg

)(

The root mean square value is indicated with the acronym RMS.

The Crest Factor is defined as the relationship between the Peak Value of a signal and its

RMS value: CF (G)=

RMS

This value changes with the signal waveform, for a purely sinusoidal wave it is

2 =1.41.

In case of distortion, the Crest Factor takes higher values as wave distortion increases.

2.3. HARMONICS

See Appendix (Par.9.4)

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HT9022

3. PREPARATION FOR USE

3.1. INITIAL CHECKS

Before shipping, the instrument has been checked from an electric as well as mechanical point of view. All possible precautions have been taken so that the instrument is delivered undamaged.

However, we recommend generally checking the instrument in order to detect possible damage suffered during transport. In case anomalies are found, immediately contact the forwarding agent.

We also recommend checking that the packaging contains all components indicated in paragraph 7.3. In case of discrepancy, please contact the Dealer.

In case the instrument should be replaced, please carefully follow the instructions given in chapter 8.2.

3.2. INSTRUMENT POWER SUPPLY

The instrument is supplied by two 1.5V LR03 AAA UM-4 batteries. Battery charge duration is approximately 54 hours of continuous use in Power mode (selector switch to “W ”).

Replace them following the instructions in paragraph 5.2.

3.3. CALIBRATION

The instrument has the technical specifications described in this manual. The instrument’s performance is guaranteed for one year.

3.4. STORAGE

In order to guarantee precise measurement, after a long storage time under extreme environmental conditions, wait for the instrument to come back to normal condition (see the environmental specifications contained in 6.2.1 before use).

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4. OPERATING INSTRUCTIONS

4.1. INSTRUMENT DESCRIPTION

4.1.1. Description of the controls

CAPTION:

1. Inductive clamp jaw

2. AC voltage indicator LED

3. Jaw trigger

4. Rotary selector switch

5. Key H / backlight

6. Function keys F1 – F2 – F3 – F4

7. LCD display

8. Input terminal VΩ

9. Input terminal COM

Fig. 1: Instrument description

4.1.2. Alignment marks

Put the conductor as close as possible to the middle of the jaws on the intersection of the indicated marks (see Fig. 2) in order to meet the meter accuracy specifications.

CAPTION:

1. Alignment marks

2. Conductor

Fig. 2: alignment marks

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4.1.3. Hand protection

CAPTION:

1. Hand protection

2. Safe area

Fig. 3: hand protection

Always keep your hands under the hand protection. This protection is always located in a suitable position to guarantee a correct safety distance from possible exposed or live parts (see Fig. 3)

4.1.4. Indication of the conventional direction of Current

The photo in Fig. 4: current direction arrow shows an arrow which indicates the conventional direction of current.

Fig. 4: current direction arrow

4.2. DESCRIPTION OF THE KEYS

4.2.1. Keys F1 – F2 – F3 – F4

Keys F1 - F2 - F3 - F4 take different functions according to the measure set (for detailed

information, see the single functions).

4.2.2. Key H

Short pressing key “H” activates the function Data HOLD, i.e. the value of the measures quantity is frozen. The symbol "H" is displayed when this function is enabled. This operating mode is disabled when key “H” is pressed again or the switch is operated.

4.2.3. Key

To improve the readability of the values measured in dark places, the display has been provided with a backlighting function (backlight), which is turned on and off by long-

pressing key “H”. This function automatically deactivates after approximately 10 seconds

after being activated, in order not to discharge the battery.

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4.3. INITIAL SCREEN

HT9022

When switching on the instrument, the initial screen appears for a few seconds. It shows:

• the instrument model;

• the serial number of the instrument;

• the firmware version in the instrument’s memory.

Sn 10120020

V. 2.00

Please note down this information, especially the firmware version, in case it should be necessary to contact the Service Department.

After a few seconds, the instrument switches to the selected function.

WARNING

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5. INSTRUMENT FUNCTIONS

5.1. PHASE DETECTION

With the selector switch set to “V ” (Voltage measurement) or “A ” (Current measurement), by taking the end of the clamp jaw near an AC source, the red LED at the base of the clamp jaw will turn on (see Fig. 1 – part 2), which indicates that current is present.

WARNING

Phase detection is not active when the clamp selector switch is set to “OFF”, “SETTINGS”, “W ”, “Ω ”,“InRush A ”.

5.2. “SETTINGS” POSITION: INSTRUMENT SETTINGS

By positioning the selector switch to “Settings”, the screen aside

will appear, containing the possible settings of the instrument.

Press keys F2, F3 (T, S) to move the cursor and key F4 (OK)

to confirm the selected item.

General

Date/Time

▼ ▲

Log InRush Continuity

19/01-17:00:00

5.2.1. General

By selecting “General”, the screen to the side will appear. Press key F1 (Sel) to move the cursor and keys F2, F3 (T, S)

to change the selected item.

Press key F4 (OK) to save the changes made and go back to

the previous screen (see par.5.2).

• Language: the language of the clamp may be chosen

among: Italian, English, Spanish. German, Swedish, Danish,

Sel

Language: Italian Auto-Off: OFF

▼ ▲

Norwegian, French, Dutch, Portuguese, Finnish and Polish.

19/01-17:00:00

• Auto-Off: the auto power off of the clamp may be set to ON or OFF. If set to ON, the

clamp will switch off after 5 minutes after it is last used.

5.2.2. Date/Time

By selecting “Date/Time”, the screen to the side will appear. Press key F1 (Sel) to move the cursor and keys F2, F3 (T, S)

to change the selected item. Item “Format” allows selecting the date and time format between EU (European) or USA (American).

Press key F4 (OK) to save the changes made and go back to

the previous screen (see par.5.2).

Sel

Year: 11 Month: 01 Day: 19 Hour: 17 Minute: 00 Format: EU

19/01-17:00:00

▼ ▲

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5.2.3. Log

▼ ▲

By selecting “Log”, the screen to the side will appear. Press keys F2, F3 (T, S) to change the duration of the

integration period. It will take the following values: 1, 5, 10, 30, 60, 120, 300, 600 or 900 seconds.

Press key F4 (OK) to save the changes made and go back to

the previous screen (see par.5.2).

Int.Period:

001 s

19/01-17:00:00

5.2.4. InRush

By selecting “InRush”, the screen to the side will appear. Press key F1 (Sel) to move the cursor and keys F2, F3 (T, S)

to change the selected item.

Press key F4 (OK) to save the changes made and go back to

the previous screen (see par.5.2).

• Thresh: threshold value beyond which the inrush current

event is detected and recorded by the instrument. The current value may be set between 5A and 900A in steps of 1A.

Sel

Thres: 080 Window: 1/1 Mode: Fix

19/01-17:00:00

▼ ▲

• Window: the value of the inrush current measuring window. The following values are

available:

¾ 1/1: sampling occurs every half-period; ¾ 1/2: sampling occurs one every two half-periods; ¾ 1/4: sampling occurs one every four half-periods;

• Mode: the inrush current measuring mode. Following modes are available:

¾ Fix; ¾ Var.

For details about the measurement of Inrush Currents see par. 5.8.2.

5.2.5. Continuity

Sel

▼ ▲

By selecting “Continuity”, the screen to the side will appear. Press keys F2, F3 (T, S) to change the setting of the resistance

limit value below which the buzzer will sound. It may be set between 1Ω and 150Ω in steps of 1Ω.

Press key F4 (OK) to save the changes made and go back to

the previous screen (see par.5.2).

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Res Lim:

010 Ω

19/01-17:00:00

HT9022

5.3. POSITION “V ”: DC, AC+DC VOLTAGE MEASUREMENT AND PHASE SEQUENCE VERIFICATION

WARNING

The maximum DC or AC+DC input voltage is 1000V. When the display shows “> 999.9V”, it means that the maximum value the clamp is able to measure has been exceeded. Exceeding these limits could result in electrical shocks to the user and damage to the instrument.

Mod Par Fnz

AC <10.0 Hz

By positioning the selector switch to “V ”, the screen to the side

will appear.

---- V

Press key F1 (Mod) to open the drop-down menu shown on the screen to the side. At each subsequent pressure of key F1, the

cursor will scroll through the available items, as follows:

• AC: AC+DC voltage measurement;

• DC: DC voltage measurement;

• Ph Seq: verification of phase sequence;

• Help: it displays the connection diagram of the instrument to

the system;

Select the desired mode and press key F4 (OK) to confirm.

5.3.1. DC voltage measurement

19/01-17:00:00

Mod Par OK

AC <10.0 Hz

Ph Seq Help

---- V

Esc

19/01-17:00:00

Fig. 5: DC voltage measurement

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Insert the red cable into the input lead VΩ and the black cable into the input lead COM

(Fig. 5), and position the leads to the desired points of the circuit being tested.

Mod Par Fnz

The screen shows an example of DC Voltage measurement.

12.0 V

5.3.1.1. Key F4 “Fnz”

Press key F4 (Fnz) to open the drop-down menu shown on the screen to the side. At each subsequent pressure of key F4, the

cursor will scroll through the available items, as follows:

• Max: it constantly displays the maximum value of the

measured DC Voltage;

• Min: it constantly displays the minimum value of the

measured DC Voltage;

• Cr+: it constantly displays the maximum positive crest value;

• Cr-: it constantly displays the minimum negative crest value;

• Rst: it deletes all stored Max, Min, Cr+ and Cr- values;

• Esc: it goes back to a normal measuring mode.

WARNING

Note: the measurement of the 4 Max, Min, Cr+ and Cr- values is simultaneous, regardless of the one displayed.

By pressing key F3 (OK), the selected item is confirmed.

To the side, an example of measurement with active Max function. The display shows the active function.

19/01-17:00:00

Mod Par OK Fnz

12.0 V

Max

Min Cr+ CrRst Esc

19/01-17:00:00

Mod Par Fnz

Max DC

12.0 V

19/01-17:00:00

5.3.1.2. Hold

Short pressing key “H” activates the function Data HOLD. The display shows the message

“H” and the screen of the measurement in progress is “frozen”.

This operating mode is deactivated when key “H” is pressed again or the switch is

operated.

5.3.1.3. Backlight

Long pressing key “H” activates or deactivates the display backlight. This function

automatically deactivates after approximately 10 seconds after being activated, in order not to discharge the batteries.

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