HT Italia HT8100 User manual

Copyright HT ITALIA 2013 Release EN 1.05 - 08/07/2013
ENGLISH
User Manual

HT8100
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.A-HOLD and RELkeys.................................................................................................................... 7
4.2.2.ENTER and CANCEL keys................................................................................................................ 7
4.2.3.HFR and Hz keys............................................................................................................................... 7
4.2.4.RANGE and MODE keys................................................................................................................... 7
4.3.Internal modes of the instrument....................................................................................... 8
4.3.1.MIN/MAX/AVG measurement............................................................................................................ 8
4.3.2.AutoTest and Manual Test mode....................................................................................................... 8
4.3.3.AC+DC mode..................................................................................................................................... 8
4.3.4.HFR mode ......................................................................................................................................... 8
4.3.5.STORE and RECALL modes............................................................................................................. 9
4.3.6.Activation/deactivation of the internal functions................................................................................. 9
4.3.7.Output DC current generation.......................................................................................................... 10
4.3.8.Loop Power and HART 250modes .............................................................................................. 10
4.4.Measuring operations...................................................................................................... 11
4.4.1.DC Voltage measurement ............................................................................................................... 11
4.4.2.AC Voltage and Frequency measurement....................................................................................... 12
4.4.3.DC Current measurement................................................................................................................ 13
4.4.4.AC Current and Frequency measurement.......................................................................................14
4.4.5.Resistance measurement and Continuity test ................................................................................. 15
4.4.6.Diode test......................................................................................................................................... 16
4.4.7.DC current generation ..................................................................................................................... 17
4.4.8.Simulation of a transducer............................................................................................................... 18
4.4.9.Measuring output DC current from external transducers (Loop) ..................................................... 19
5.MAINTENANCE .........................................................................................................20
5.1.Replacing the batteries and the internal fuses................................................................ 20
5.2.Cleaning the instrument .................................................................................................. 20
5.3.End of life ........................................................................................................................ 20
6.TECHNICAL SPECIFICATIONS ................................................................................21
6.1.Technical characteristics................................................................................................. 21
6.1.1.Electrical characteristics .................................................................................................................. 23
6.1.2.Considered standards...................................................................................................................... 23
6.1.3.General characteristics.................................................................................................................... 23
6.2.Environment.................................................................................................................... 24
6.2.1.Environmental conditions for use..................................................................................................... 24
6.3.Accessories..................................................................................................................... 24
6.3.1.Accessories provided....................................................................................................................... 24
7.SERVICE....................................................................................................................25
7.1.Warranty conditions......................................................................................................... 25
7.2.Service ............................................................................................................................ 25

HT8100
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 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 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:
Warning: 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
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
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
In case the lack of warning against the presence of voltage may constitute a danger for
the operator 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
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 § 6.2.1.
Check that the batteries are correctly inserted.
Make sure that the LCD display and the switch indicate the same function.

HT8100
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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.

HT8100
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2. GENERAL DESCRIPTION
HT8100 carries out the following measurements:
DC and AC+DC TRMS voltage
DC and AC+DC TRMS current
Resistance and Continuity test
AC voltage and current frequency
Diode test
Current generation with amplitude up to 24mA DC with display in mAand %
Generation with selectable ramp outputs
Output current measurement from transducers (Loop), HART250resistor included
Simulation of an external transducer
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 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 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.

HT8100
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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 battery discharge, batteries have not been inserted in the instrument.
For battery installation, follow the instructions given in § 5.1
When 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).

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4. OPERATING INSTRUCTIONS
4.1. INSTRUMENT DESCRIPTION
CAPTION:
1. Auto Backlight
2. LCD display
3. Function keys
4. MODE key
5. Rotary selector switch
6. Input terminal COM
7. Input terminal mA
8. Input terminal HzV
9. Input terminal A
Fig. 1: Instrument description

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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. A-HOLD and RELkeys
Pressing the A-HOLD key in any function, except for the current generation function
and diode test function, keeps the value of the measured quantity shown on the
display. The message “HOLD” appears on the display. The Auto HOLD function allows
the instrument to provide a steady result on the display even with variable input signal
(> 50dgt). For readings less than 0.1V (V measure), 1mV (mV measure), no limit (other
measures) the A-HOLD feature is not active. Press the HOLD key again, the MODE
key or turn the rotary switch to exit the function.
Pressing the RELkey in any function, except for , , measurements and the
current generation function, allows carrying out the relative measurement of the
quantity to be tested. The symbol “” appears on the display, initially steady. When
pressing the key, the symbol “” 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 and hold the
RELkey for more than 1 second, the MODE key, the RANGE key or turn the rotary
switch to exit the function.
4.2.2. ENTER and CANCEL keys
Pressing the ENTER key allows activating a function flashing on the display, selected
by means of the 4-arrow selector located on the front panel of the instrument.
Pressing the CANCEL key allows exiting a function flashing on the display, selected by
means of the 4-arrow selector located on the front panel of the instrument, thus going
back to real time measurement.
4.2.3. HFR and Hz keys
Pressing the HFR key, which can be used in positions V, mVand A, allows
activating AC voltage or current measurement in “HFR” mode (see § 4.3.4). Press the
HFR key or turn the rotary switch to exit the function.
Pressing the Hz key, which can be used in positions V, mVand A, allows
displaying the AC voltage or current frequency measure. The symbol “Hz” is shown on
the display. Press the Hz key, the MODE key or turn the rotary switch to exit the
function.
4.2.4. RANGE and MODE keys
Pressing the RANGE key allows manually selecting the measuring range of functions
V, mV and . The symbol “AUTO RANGE” 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 more than 1 second or turn the rotary switch to exit
the function and restore the symbol “AUTO RANGE” on the display.
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 § 4.3.2).
Disabling the Auto Power OFF function (see § 4.3.6).

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4.3. INTERNAL MODES OF THE INSTRUMENT
4.3.1. MIN/MAX/AVG measurement
In any function, except for the current generation function, it is possible to activate the
detection of the Maximum, Minimum and Average (AVG) values of the quantity being
tested as follows:
1. Use the 4-arrow selector to select the “MAX”, “MIN” or “AVG” symbols flashing at the
bottom of the display.
2. Confirm selection by pressing the ENTER key.
3. The 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 symbol
“AVG” shows on the display the value of the average between the maximum and the
minimum value currently shown on the display.
4. Press the CANCEL key or turn the rotary switch to exit the function.
4.3.2. AutoTest and Manual Test mode
In measuring functions “V”, “mV” and “A” 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.
4.3.3. AC+DC mode
When measuring voltage and current, by pressing the MODE key it is possible to select
the “AC+DC” measuring mode, which also allows evaluating a possible presence of
overlapping direct components on a generic alternating waveform. This can be useful
when measuring typical impulsive signals of non-linear loads (e.g. welding machines,
electric ovens, etc.).
4.3.4. HFR mode
In measuring functions “V”, “mV” and “A”, by pressing the HFR 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 800Hz,
and this allows eliminating different harmonic components from it. Press the HFR key to
exit the “HFR” mode.

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4.3.5. STORE and RECALL modes
For each measuring function, except for the current generation function, it is possible to
save the displayed value in the instrument’s memory and to recall the data saved on the
display at any time. The instrument allows saving max. 100 pieces of data in the memory.
Proceed as follows:
Data saving
1. Select the “STORE” symbol flashing on the display, using the 4-arrow selector located
on the front panel of the instrument.
2. Press the ENTER key to save the data in the memory. The number of the memory
location is immediately shown on the secondary display of the instrument.
Recalling on the display and deleting the internal memory
1. Select the “RECALL” symbol flashing on the display, using the 4-arrow selector located
on the front panel of the instrument.
2. Press the ENTER key. The display shows the value of the measure corresponding to
the last memory location used and the number of the location itself.
3. Use the up or down arrow key of the 4-arrow selector located on the front panel of the
instrument to select the desired location. Press and hold the arrow keys for more than
1 second in order to carry out a quick search.
4. Press the CANCEL key to exit the function.
5. Switch off the instrument, then switch on the instrument again while pressing and
holding the CANCEL key to delete the internal memory.
4.3.6. Activation/deactivation of the internal functions
The following actions can be activated by pressing and holding the function keys indicated
in Table 1 when switching on the instrument:
Key Action
RANGE Setting of the modes 0-20mA or 4-20mA of current generation used by
default by the instrument (see § 4.3.7)
MODE
Deactivation of the Auto power off function. The message “APO Off” is
provided by the instrument and the indication “APO” disappears from
the display. The function is automatically re-activated upon the
following instrument start-up.
HFR Display of the internal Firmware version of the instrument.
ENTER
A
ctivation/deactivation by default of the sound associated with the
pressure of the function keys. The messages “Beep On” or “Beep Off”
appear on the display.
CANCEL Clearing of the instrument’s internal memory. The message “Clr” is
immediately shown on the display.
A-HOLD
A
ctivation of continuous backlighting. The message “Blt On” is
immediately shown on the display. The function is automatically
disabled upon the following instrument start-up.
REL Complete deactivation of backlighting. The message “Blt Off” is
immediately shown on the display. The function is automatically
disabled upon the following instrument start-up.
Table 1: List of internal functions of the instrument

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4.3.7. Output DC current generation
The “OUTPUT” section of the function selector switch defines the possibility of generating
an output DC current with the instrument, considering the selectable measuring ranges 0-
20mA or 4-20mA. The instrument may operate in the following modes:
DC current source DC current generation (see § 4.4.7).
Simulation simulation of a transducer in a current loop with auxiliary power supply
(see § 4.4.8)
The positions of the rotary switch are the following:
mA Output DC current, which may be selected as indicated in Table 2
Percentage value (% STEP) Range 0-20mA Range 4-20mA
0% 0mA 4mA
25% 5mA 8mA
50% 10mA 12mA
75% 15mA 16mA
100% 20mA 20mA
120% 24mA Not available
125% Not available 24mA
Table 2: Selectable values of output DC current
Output current adjustment is possible with the options:
%STEP setting of values 0%, 25%, 50%, 75%, 100%, 120%, 125% of the selected
range.
Quick adjustment setting of values 0%, 50%, 100% of the selected range.
FINE setting of custom values in the range 0 ÷ 24mA with resolution of 1µA.
mA Output DC current with automatic ramp as indicated in Table 3
Ramp type Description Action
Slow linear ramp Passage from 0% 100% 0% in 40s
Quick linear ramp Passage from 0% 100% 0% in 20s
Slow step ramp 0% 100% 0% with ramps of 15s
Quick step ramp 0% 100% 0% with ramps of 5s
Table 3: List of available ramps for output current
4.3.8. Loop Power and HART 250modes
In the LOOP POWER function, the instrument is capable of generating an output voltage >
24V DC to supply an external transducer and directly measure the corresponding loop
current.
The HART 250function allows setting a 250internal resistor for loop measurement on
transducers operating with HART(Highway Addressable Remote Transducer) protocol.

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4.4. MEASURING OPERATIONS
4.4.1. DC Voltage measurement
CAUTION
The maximum input DC voltage is 1000 V. Do not measure voltages
exceeding the limits given in this manual. Exceeding voltage limits could
result in electrical shocks to the user and damage to the instrument.
Fig. 2: Use of the instrument for DC voltage measurement
1. Select positions Vor mV
2. Press the MODE key for manually selecting “DC” measurement.
3. Use the RANGE key for manually selecting the measuring range (see § 4.2.4) or use
Autorange selection. If voltage value is unknown, select the highest range.
4. Insert the red cable into input lead HzVand the black cable into input lead COM
5. Position the red lead and the black lead respectively in the points with positive and
negative potential of the circuit to be measured (see Fig. 2). The display shows the
value of voltage
6. If the display shows the message “OL”, select a higher range.
7. When symbol “-” appears on the instrument’s display, it means that voltage has the
opposite direction with respect to the connection in Fig. 2
8. For using the HOLD function see § 4.2.1, for measuring MAX/MIN/AVG values see
§ 4.3.1, for relative measurement see § 4.2.1 and for saving the result see § 4.3.5.

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4.4.2. AC Voltage and Frequency measurement
CAUTION
The maximum input AC voltage is 1000Vrms. Do not measure voltages
exceeding the limits given in this manual. Exceeding voltage limits could
result in electrical shocks to the user and damage to the instrument.
Fig. 3: Use of the instrument for AC voltage measurement
1. Select positions Vor mV
2. Press the MODE key for manually selecting “AC” or “AC+DC” measurement (see
§ 4.3.3) or press the HFR key for “HFR” measurement (see § 4.3.4).
3. Use the RANGE key for manually selecting the measuring range (see § 4.2.4) or use
Autorange selection. If voltage value is unknown, select the highest range.
4. Insert the red cable into input lead HzVand the black cable into input lead COM
5. Position the red lead and the black lead respectively in the points of the circuit to be
measured (see Fig. 3). The display shows the value of voltage.
6. If the display shows the message “OL”, select a higher range.
7. Press the Hz key to display the frequency measure of AC voltage. The symbol “Hz” is
shown on the display.
8. For using the HOLD function see § 4.2.1, for measuring MAX/MIN/AVG values see
§ 4.3.1, for relative measurement see § 4.2.1 and for saving the result see § 4.3.5.

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4.4.3. DC Current measurement
CAUTION
The maximum input DC current is 1A. Do not measure currents exceeding
the limits given in this manual. Exceeding current limits could result in
electrical shocks to the user and damage to the instrument.
Fig. 4: Use of the instrument for DC current measurement
1. Cut off power supply from the circuit to be measured.
2. Select position Aor mA (for measuring currents <50mA).
3. Press the MODE key for manually selecting “DC” measurement.
4. Insert the red cable into input lead mA or Aand the black cable into input lead
COM.
5. Connect the red lead and the black lead in series to the circuit whose current you want
to measure, respecting polarity and current direction (see Fig. 4)
6. Supply the circuit to be measured. The display shows the value of current.
7. If the display shows the message “OL”, the maximum measurable value has been
reached.
8. When symbol “-” appears on the instrument’s display, it means that current has the
opposite direction with respect to the connection in Fig. 4
9. For using the HOLD function see § 4.2.1, for measuring MAX/MIN/AVG values see
§ 4.3.1, for relative measurement see § 4.2.1 and for saving the result see § 4.3.5

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4.4.4. AC Current and Frequency measurement
CAUTION
The maximum input AC current is 1A. Do not measure currents exceeding
the limits given in this manual. Exceeding current limits could result in
electrical shocks to the user and damage to the instrument.
Fig. 5: Use of the instrument for AC current measurement
1. Cut off power supply from the circuit to be measured.
2. Select position Aor mA (for measuring currents <50mA).
3. Press the MODE key for manually selecting “AC” or “AC+DC” measurement (see
§ 4.3.3) or press the HFR key for “HFR” measurement (see § 4.3.4).
4. Insert the red cable into input lead mA or Aand the black cable into input lead
COM
5. Connect the red lead and the black lead in series to the circuit whose current you want
to measure (see Fig. 5)
6. Supply the circuit to be measured. The display shows the value of current.
7. If the display shows the message “OL”, the maximum measurable value has been
reached.
8. Press the Hz key to display the frequency measure of AC current. The symbol “Hz” is
shown on the display.
9. For using the HOLD function see § 4.2.1, for measuring MAX/MIN/AVG values see
§ 4.3.1, for relative measurement see § 4.2.1 and for saving the result see § 4.3.5.

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4.4.5. Resistance measurement and Continuity test
CAUTION
Before attempting any resistance measurement, cut off power supply from
the circuit to be measured and make sure that all capacitors are discharged,
if present.
Fig. 6: Use of the instrument for resistance measurement and continuity test
1. Select the position. The symbol “M” is shown on the display
2. Use the RANGE key for manually selecting the measuring range (see § 4.2.4) or use
Autorange selection. If the value of resistance is unknown, select the highest range
3. Insert the red cable into input lead HzVand the black cable into input lead COM
4. Position the test leads in the desired points of the circuit to be measured (see Fig. 6).
The display shows the value of resistance
5. If the display shows the message “OL”, select a higher range.
6. Press the MODE key to select the Continuity test. The symbol “ ” is shown on the
display. Insert the red and black cables as instructed for resistance measurement. The
buzzer activates for resistance values <30
7. For using the HOLD function see § 4.2.1, for measuring MAX/MIN/AVG values see
§ 4.3.1 and for saving the result see § 4.3.5

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4.4.6. Diode test
CAUTION
Before attempting any diode test, cut off power supply from the circuit to be
measured and make sure that all capacitors are discharged, if present.
Fig. 7: Use of the instrument for diode test
1. Select the position
2. Press the MODE key to select the Diode Test. The symbol “ ” is shown on the display
3. Insert the red cable into input lead HzVand the black cable into input lead COM.
4. Position the leads at the ends of the diode to be tested, respecting the indicated
polarity (see Fig. 7). The value of directly polarized threshold voltage is shown on the
display. For a good P-N junction, the instrument must show a value between 0.4 and
0.9V. If threshold value is equal to 0mV, the P-N junction of the diode is short-circuited.
5. If the instrument shows the message “OL”, the terminals of the diode are reversed with
respect to the indication given in Fig. 7 otherwise, the P-N junction of the diode is
damaged
6. For using the HOLD function see § 4.2.1, for measuring MAX/MIN/AVG values see
§ 4.3.1 and for saving the result see § 4.3.5

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4.4.7. DC current generation
CAUTION
The maximum output DC current generated by the instrument is 24mA with
internal battery voltage > 4.5VDC.
Fig. 8: Use of the instrument for DC current generation
1. Switch on the instrument by pressing and holding the RANGE key to select the
measuring range 0-20mA or 4-20mA.
2. Select the position mA in case of programmable DC current generation or position
mA for DC current generation with automatic ramp.
3. Use the 4-arrow selector on the front panel to select the options “%STEP”, “100%”,
“50%”, “0%” or “END” flashing on the display and confirm with the ENTER key in case
of selectable current generation, or press the MODE key to select the ramp type (see
§ 4.3.7)
4. Insert the red cable into input lead Aand the black cable into input lead mA . The
instrument automatically generates the output current considering the selected options.
Press the A-HOLD key to suspend/restore the generation
5. Position the red lead and the black lead respectively in the points with positive and
negative potential of the passive external device which must be supplied (see Fig. 8)
6. Turn the rotary switch to exit the function and stop generation. Remove the cable from
lead Abefore turning the rotary switch.

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4.4.8. Simulation of a transducer
CAUTION
In this mode, the instrument provides an adjustable output current up to
24mADC. It is necessary to provide an external power supply with voltage
between 6V and 48VDC in order to adjust current.
Fig. 9: Use of the instrument for simulating a transducer
1. Switch on the instrument by pressing and holding the RANGE key to select the
measuring range 0-20mA or 4-20mA.
2. Select the position mA in case of programmable DC current generation or position
mA for DC current generation with automatic ramp.
3. Use the 4-arrow selector on the front panel to select the options “%STEP”, “100%”,
“50%”, “0%” or “END” flashing on the display and confirm with the ENTER key in case
of selectable current generation, or press the MODE key to select the ramp type (see
§ 4.3.7)
4. Insert the red cable into input lead mA and the black cable into input lead COM. The
instrument automatically generates the output current considering the selected options.
Press the A-HOLD key to suspend/restore the generation
5. Position the red lead and the black lead respectively in the points with positive potential
of the external source and positive potential of the external measuring device (e.g.:
multimeter – see Fig. 9)
6. Turn the rotary switch to exit the function and stop generation. Remove the cable from
lead mA before turning the rotary switch.

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4.4.9. Measuring output DC current from external transducers (Loop)
CAUTION
In this mode, the instrument provides an output voltage > 24VDC / 20mA,
capable of supplying an external transducer and allowing measuring loop
current at the same time.
Fig. 10: Use of the instrument for measuring output DC current from external transducers
1. Cut off power supply from the circuit to be measured.
2. Select the position mA LOOP POWER. The message “LOOP POWER” is shown on
the display. If necessary, press the MODE key for selecting the 250HART mode (see
§ 4.3.8). The message “250HART” is shown on the display.
3. Insert the red cable into input lead Aand the black cable into input lead mA .
4. Connect the red lead and the black lead to the external transducer, respecting current
polarity and direction (see Fig. 10)
5. Supply the circuit to be measured. The display shows the value of current.
6. The message “OL” indicates that the current being measured exceeds the maximum
value measurable by the instrument.
7. For using the HOLD function see § 4.2.1, for measuring MAX/MIN/AVG values see
§ 4.3.1, for relative measurement see § 4.2.1 and for saving the result see § 4.3.5.
8. Turn the rotary switch to exit the function. Remove the cable from lead Abefore
turning the rotary switch.