HT HT701 User manual

Copyright HT ITALIA 2012 Version EN 1.01 - 19/03/2012
ENGLISH
User manual

HT701
EN - 1
Table of contents:
1.PRECAUTIONS AND SAFETY MEASURES...............................................................2
1.1.Preliminary instructions..................................................................................................... 2
1.2.During use......................................................................................................................... 3
1.3.After use............................................................................................................................ 3
1.4.Definition of measurement (overvoltage) category............................................................ 3
2.GENERAL DESCRIPTION...........................................................................................4
2.1.Measuring average values and TRMS values................................................................... 4
2.2.Definition of true root mean square value and crest factor................................................ 4
3.PREPARATION FOR USE...........................................................................................5
3.1.Initial checks...................................................................................................................... 5
3.2.Instrument power supply................................................................................................... 5
3.3.Calibration......................................................................................................................... 5
3.4.Storage.............................................................................................................................. 5
4.OPERATING INSTRUCTIONS.....................................................................................6
4.1.Instrument description....................................................................................................... 6
4.2.Description of function keys .............................................................................................. 7
4.2.1.HOLD/LOCK key ........................................................................................................................ 7
4.2.2.MAX/MIN/key.......................................................................................................................... 7
4.2.3.Hz/0/key........................................................................................................................... 7
4.2.4.MODE key .................................................................................................................................. 7
4.2.5.STORE/RECALL key.................................................................................................................. 8
4.2.6.RANGE/50V-1kV key ................................................................................................................. 8
4.2.7.TEST key.................................................................................................................................... 8
4.3.Internal modes of the instrument....................................................................................... 9
4.3.1.Deactivation of the Autobacklight function ................................................................................. 9
4.3.2.Deactivation of the Auto power off function................................................................................ 9
4.3.3.AutoTest and Manual Test mode ............................................................................................... 9
4.3.4.HFR mode .................................................................................................................................. 9
4.3.5.SMOOTH mode.......................................................................................................................... 9
4.3.6.Integrity test on internal fuse ...................................................................................................... 9
4.4.Measuring operations...................................................................................................... 10
4.4.1.DC Voltage measurement........................................................................................................ 10
4.4.2.AC Voltage and Frequency measurement............................................................................... 11
4.4.3.DC Current measurement ........................................................................................................ 12
4.4.4.AC current and frequency measurement ................................................................................. 13
4.4.5.Resistance measurement and continuity test........................................................................... 14
4.4.6.Diode test.................................................................................................................................. 15
4.4.7.Capacitance measurement....................................................................................................... 16
4.4.8.Temperature measurement...................................................................................................... 17
4.4.9.Insulation resistance measurement.......................................................................................... 18
5.MAINTENANCE .........................................................................................................19
5.1.Replacing the batteries and the internal fuse.................................................................. 19
5.2.Cleaning the instrument .................................................................................................. 19
5.3.End of life ........................................................................................................................ 19
6.TECHNICAL SPECIFICATIONS ................................................................................20
6.1.Technical characteristics................................................................................................. 20
6.1.1.Electrical characteristics........................................................................................................... 23
6.1.2.Considered standards .............................................................................................................. 23
6.1.3.General characteristics............................................................................................................. 23
6.2.Environment.................................................................................................................... 23
6.2.1.Environmental conditions for use ............................................................................................. 23
6.3.Accessories..................................................................................................................... 24
6.3.1.Standard accessories............................................................................................................... 24
6.3.2.Optional accessories................................................................................................................ 24
7.SERVICE....................................................................................................................25
7.1.Warranty conditions......................................................................................................... 25
7.2.Service ............................................................................................................................ 25

HT701
EN - 2
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 measurement in humid environments.
Do not carry out any measurements in case gas, explosive materials or flammables are
present, or in dusty environments.
Avoid any contact with the circuit being measured if no measurements are being
carried out.
Avoid any contact with exposed metal parts, with unused measuring probes, circuits,
etc.
Do not carry out any measurement in case you find anomalies 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.
The following symbols are used in this manual:
Caution: observe the instructions given in this manual; an improper use could
damage the instrument or its components
Presence of dangerous voltage (30V): electrical shock hazard
Double-insulated meter
AC voltage or current
DC voltage or current
Connection to earth
When measuring insulation, do not apply between input terminals any voltage
higher than 600V DC/ACrms
1.1. PRELIMINARY INSTRUCTIONS
This instrument has been designed for use in environments of pollution degree 2.
It can be used for VOLTAGE and CURRENT measurements on installations with CAT
III 1000V and CAT IV 600V.
Follow the normal safety rules devised 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 be replaced with identical models,
when necessary.
Do not test circuits exceeding the specified voltage limits.
Do not perform any test under environmental conditions exceeding the limits indicated
in §s 6.1.1 and 6.2.1.
Check that the batteries are 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.

HT701
EN - 3
1.2. DURING USE
Please carefully read the following recommendations and instructions:
CAUTION
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 rotary switch, 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.
Avoid measuring resistance if external voltages are present. Even if the instrument is
protected, excessive voltage could cause a malfunction of the instrument.
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, set the rotary switch to OFF to turn off the instrument.
If the instrument is not to be used for a long time, remove the batteries.
1.4. DEFINITION OF MEASUREMENT (OVERVOLTAGE) CATEGORY
Standard “CEI 61010-1: Safety requirements for electrical equipment for measurement,
control and laboratory use, Part 1: General requirements” defines what measurement
category, commonly called overvoltage category, is. § 6.7.4: Measured circuits, reads:
(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 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.

HT701
EN - 4
2. GENERAL DESCRIPTION
Instrument HT701 carries out the following measurements:
DC and AC TRMS voltage
DC and AC TRMS current
Resistance and Continuity test
Insulation resistance with test voltage of 50, 100, 250, 500, 1000VDC
AC voltage and current frequency
Capacity
Diode test
Temperature with K-type probe
Each of these functions can be selected using the 8-position rotary switch, including an
OFF position. The instrument is also equipped with function keys (see § 4.2) and an
analogue graphic bar. The selected quantity appears on the LCD display with the
indication of the measuring unit and of the enabled functions.
The instrument is also equipped with an automatic display backlighting function
(Autobacklight) and with an Auto Power OFF function which automatically switches off the
instrument approx. 20 minutes after the last time a function key was pressed or the rotary
switch was turned. To switch on the instrument again, turn the rotary switch.
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 (50 or 60 Hz).
TRMS (True Root Mean Square) VALUE meters: instruments measuring the TRMS
value of the quantity being tested.
With a perfectly sinusoidal wave, the two families of instruments provide identical results.
With distorted waves, instead, the rdgs 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 with an 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 an intensity of 1A”. This definition results in the numeric
expression:
G= 
Tt
t
dttg
T
0
0
)(
12The 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
p
G
GThis 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.

HT701
EN - 5
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 §
6.3.1. In case of discrepancy, please contact the Dealer.
In case the instrument should be returned, please follow the instructions given in § 7.
3.2. INSTRUMENT POWER SUPPLY
The instrument is supplied with four 1.5V AA IEC LR6 alkaline batteries, included in the
package.
In order to prevent compromising its charge, the battery is not inserted in the instrument.
For battery installation, follow the instructions given in § 5.1
When the batteries are flat, the symbol “ ” appears on the display. To replace/insert the
batteries, see § 5.1.
3.3. CALIBRATION
The instrument has the technical specifications described in this manual. The instrument’s
performance is guaranteed for 12 months.
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).

HT701
EN - 6
4. OPERATING INSTRUCTIONS
4.1. INSTRUMENT DESCRIPTION
CAPTION:
1. Auto Backlight
2. LCD display
3. STORE/RECALL key
4. HOLD/LOCK key
5. RANGE key
6. Hz/0key
7. MAX/MIN key
8. MODE key
9. TEST key
10. Rotary selector switch
11. Input terminal Hz°CV
12. Input terminal COM
13. Input terminal
INSULATION
14. Input terminal mA
Fig. 1: Instrument description

HT701
EN - 7
4.2. DESCRIPTION OF FUNCTION KEYS
The following § describes the functions of the different keys. When pressing a key, the
display shows the symbol of the activated function and the buzzer sounds.
4.2.1. HOLD/LOCK key
Pressing the HOLD/LOCK key:
in any function, except for the insulation measurement, keeps the value of the
measured quantity shown on the display. The message “HOLD” appears on the
display. Press the HOLD key again, the MODE key, the RANGE key or turn the rotary
switch to exit the function.
When measuring insulation (see § 4.4.9), pressing the HOLD/LOCK key allows
blocking the test voltage set and carrying out a continuous measurement. The symbols
“” and “LOCK” appear on the display. Press the TEST key to exit the function.
4.2.2. MAX/MIN/key
Pressing the MAX/MIN/key:
in any function, except for insulation measurement, activates the detection of
Maximum, Minimum and Average (AVG) values of the quantity being tested. Both
values are constantly updated, as soon as the instrument measures a higher (MAX) or
lower (MIN) value. The display shows the symbol associated with the selected function:
“MAX” for maximum value and “MIN” for minimum value. The flashing symbol “MAX
MIN” shows the current value on the display. The symbol “AVG” shows on the display
the value of the average between the maximum and the minimum value currently
shown on the display. Press and hold the MAX/MIN/key for 2 seconds, the MODE
key, the RANGE key or turn the rotary switch to exit the function.
In “RECALL” function (recalling the data saved in the memory on the display – see §
4.2.5), the key allows selecting the memory cell before the one currently shown on
the display.
4.2.3. Hz/0/key
Pressing the Hz/0/key:
in functions “V”, “mV” and “mA” allows selecting voltage or current frequency
measurement. The symbol “Hz” is shown on the display. Press the key again or turn
the rotary switch to exit the function.
In functions “ ” and “” (for values < approx. 3- e.g.: short-circuited test leads) it
allows measuring the quantity to be tested. The symbol “0” appears on the display,
initially steady. When pressing the key, the symbol “0” flashes and the value of the
quantity being tested is saved as offset for the following measurements. The display
shows the relative value, obtained as: relative value (displayed) = current value –
offset. Press the Hz/0/key, the MODE key, the RANGE key or turn the rotary
switch to exit the function.
In “RECALL” function (recalling the data saved in the memory on the display – see §
4.2.5), the key allows selecting the memory cell after the one currently shown on the
display.
4.2.4. MODE key
The MODE key allows:
Selecting the functions on the rotary switch, highlighted in orange.
Quitting sub-functions selected on the instrument.
Switching from AutoTest mode to Manual mode (see § 4.3.3).
Deleting the internal memory of the instrument (see § 4.2.5)

HT701
EN - 8
4.2.5. STORE/RECALL key
The STORE/RECALL key carries out the following operations:
Simply pressing the key allows saving the value on the display in the memory. The
symbol “MEM” flashes for a second and the considered memory location is
immediately indicated on the display. Each measuring function has its own dedicated
memory space for a maximum of 100 available locations for each of them.
Pressing and holding the key for 2 seconds allows recalling the data saved in the
internal memory on the display. The symbol “MEM” and the indication of the last
memory location are shown on the display together with the measurement result. Press
the keys or to select the desired memory location. Press and hold the keys or
for 2 seconds to rapidly select the memory locations.
Press and hold the MODE key for 2 seconds to delete the whole instrument memory.
The message “nOnE” is shown on the display and the indication of the memory
location is taken back to “0”. As an alternative, press and hold the STORE/RECALL
key while switching on the instrument.
Press the STORE/RECALL key again or turn the rotary switch to exit the function.
4.2.6. RANGE/50V-1kV key
Pressing the RANGE/50V-1kV key allows the following operations:
Manual selection of the measuring range of the different functions (except for positions
,, °C and °F and insulation measurement). The symbol “AUTO” disappears from
the display and the cyclic pressure of the key modifies the position of the decimal point
on the display. Press and hold the RANGE key for 2 seconds or turn the rotary switch
to exit the function and restore the symbol “AUTO” on the display.
Selecting the test voltage in insulation measurement (see § 4.4.9) among the following
values: 50V, 100V, 250V, 500V and 1000VDC. The symbols of the selected voltages
are shown at the bottom of the display on the right.
Quitting sub-functions selected on the instrument.
4.2.7. TEST key
Pressing the TEST key allows activating the insulation resistance measurement on the
instrument (see § 4.4.9).

HT701
EN - 9
4.3. INTERNAL MODES OF THE INSTRUMENT
4.3.1. Deactivation of the Autobacklight function
The instrument has a display backlighting function (see Fig.1 – part 1) which activates
automatically in conditions of poor visibility. The function deactivates automatically after a
few seconds. To manually disable the function, proceed as follows:
1. Switch off the instrument (OFF).
2. Turn the rotary switch in any position, keeping the MAX/MIN key pressed until the
display has completely turned on.
3. Switch off and then on again the instrument to enable the function.
4.3.2. Deactivation of the Auto power off function
In order to preserve internal batteries, the instrument switches automatically off 20 minutes
after it was last used. The symbol “APO” appears on the display when this function is
active. When the instrument must be used for long periods of time, it may be useful to
deactivate the Auto Power Off function as follows:
1. Switch off the instrument (OFF).
2. Turn the rotary switch in any position, keeping the MODE key pressed until the display
has completely turned on. The symbol “APO” disappears.
3. Switch off and then on again the instrument to enable the function.
4.3.3. AutoTest and Manual Test mode
In measuring functions “V”, “mV” and “mA” it is possible to use the following two modes:
AutoTest it allows the automatic detection of AC or DC measurement of voltage or
current. The message “AUTOTEST” is shown on the display. This is the mode set
whenever the instrument is switched on.
Manual Test it allows manually setting the AC or DC measurement of voltage or
current.
Press the MODE key to switch from AutoTest mode to Manual mode. The message
“AUTOTEST” disappears from the display and the modes “DC” or “AC” can be selected by
pressing the MODE key again. Press and hold the MODE key for 2 seconds to go back to
the AutoTest mode, or switch off and then on again the instrument.
4.3.4. HFR mode
In measuring function “V”, when pressing the MODE key in Manual mode, it is possible to
select “HFR” (High Frequency Reject) measurement. In this case, the AC voltage
measurement is carried out considering a maximum signal frequency of 500Hz, and this
allows eliminating different harmonic components from it.
Press the MODE key to exit the “HFR” mode.
4.3.5. SMOOTH mode
In insulation resistance measuring mode, by pressing the MODE key it is possible to select
the “SMOOTH” mode, which enables a greater stability of the result displayed. Press the
MODE key to exit the “SMOOTH” mode.
4.3.6. Integrity test on internal fuse
The instrument allows testing the status of the internal fuse as follows:
1 Insert a test lead into input terminal Hz°CV.
2 Turn the rotary switch to . Press the MODE key to select diode test (symbol
“” on the display).
3 Insert the test lead into input mA. With indication of a result typically <2V Fuse OK.
With indication “OL” the fuse must be replaced.