HT PV-ISOTEST User manual

Copyright HT ITALIA 2020 Release EN 1.00 - 30/11/2020
PV-ISOTEST
User manual

PV-ISOTEST
EN - 1
TABLE OF CONTENTS
1.PRECAUTIONS AND SAFETY MEASURES ...............................................................3
1.1.Preliminary instructions ..................................................................................................... 3
1.2.During use......................................................................................................................... 4
1.3.After use............................................................................................................................ 4
1.4.Definition of measurement (overvoltage) category............................................................ 4
2.GENERAL DESCRIPTION ...........................................................................................5
2.1.Foreword ........................................................................................................................... 5
2.2.Instrument functions.......................................................................................................... 5
3.PREPARATION FOR USE ...........................................................................................6
3.1.Initial checks...................................................................................................................... 6
3.2.Instrument power supply ................................................................................................... 6
3.3.Storage.............................................................................................................................. 6
4.NOMENCLATURE........................................................................................................7
4.1.Description of the instrument............................................................................................. 7
4.2.Keyboard description......................................................................................................... 8
4.3.Display description ............................................................................................................ 8
4.4.Initial screen ...................................................................................................................... 8
5.GENERAL MENU.........................................................................................................9
5.1.SET – instrument settings ................................................................................................. 9
5.1.1.Language ................................................................................................................................. 9
5.1.2.Date and time........................................................................................................................... 9
5.1.3.General .................................................................................................................................. 10
5.1.4.Info ......................................................................................................................................... 10
6.OPERATING INSTRUCTIONS...................................................................................11
6.1.RPE – Continuity measurement on modules/strings/PV fields........................................ 11
6.1.1.Calibration of measuring cables ............................................................................................ 11
6.1.2.Carrying out continuity measurements in Standard (STD) mode.......................................... 13
6.1.3.Carrying out continuity measurements in Timer (TMR) mode............................................... 15
6.1.4.Anomalous situations............................................................................................................. 17
6.2.M– Measurement of insulation on PV modules/strings/fields ...................................... 18
6.2.1.Measuring insulation – DUAL mode ...................................................................................... 18
6.2.2.Measuring insulation – TMR mode........................................................................................ 20
6.2.3.Anomalous situations............................................................................................................. 23
6.3.GFL – Searching for conditions of low insulation on PV strings...................................... 25
6.4.DMM – Multimeter function ............................................................................................. 29
7.STORING RESULTS..................................................................................................30
7.1.Saving measures............................................................................................................. 30
7.2.Recall of data to display and memory deletion................................................................ 31
8.CONNECTING THE INSTRUMENT TO THE PC.......................................................32
9.MAINTENANCE..........................................................................................................33
9.1.General information......................................................................................................... 33
9.2.Battery replacement ........................................................................................................ 33
9.3.Cleaning the instrument .................................................................................................. 33
9.4.End of life ........................................................................................................................ 33
10.TECHNICAL SPECIFICATIONS.................................................................................34
10.1.Technical characteristics................................................................................................. 34
10.2.General characteristics.................................................................................................... 35
10.2.1.Reference gudelines.............................................................................................................. 35
10.2.2.Display and memory .............................................................................................................. 35
10.2.3.Power supply ......................................................................................................................... 35
10.2.4.Mechanical characteristics..................................................................................................... 35
10.3.Environmental conditions for use .................................................................................... 35
10.4.Accessories..................................................................................................................... 35
11.APPENDIX – THEORETICAL OUTLINE ....................................................................36
11.1.Measurement of polarization index (PI)........................................................................... 36

PV-ISOTEST
EN - 2
11.2.Dielectric Absorption Ratio (DAR)................................................................................... 36
12.ASSISTANCE.............................................................................................................37
12.1.Warranty conditions......................................................................................................... 37
12.2.Assistance....................................................................................................................... 37

PV-ISOTEST
EN - 3
1. PRECAUTIONS AND SAFETY MEASURES
The instrument has been designed in compliance with directive IEC/EN61010-1 relevant to
electronic measuring instruments. Before and while carrying out measurements, observe
the following indications and read all notes preceded by the symbol with the utmost
attention.
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 any contact with the circuit being measured if no measurements are being
carried out.
Avoid contact with exposed metal parts, with unused measuring probes, etc.
Do not carry out any measurement in case you find anomalies in the instrument such
as deformation, breaks, absence of display on the screen, etc.
Pay special attention when measuring voltages higher than 25V in special
environments and 50V in normal environments, 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; improper use could
damage the instrument or its components.
High voltage danger: electrical shock hazard.
Double insulation
DC voltage
AC voltage
Connection to earth
1.1. PRELIMINARY INSTRUCTIONS
This instrument has been designed for use in the environmental conditions specified in
section § 10.3. Do not use in different environmental conditions.
The instrument may be used for measuring VOLTAGE in CAT III 1500VDC and CAT III
1000VAC with a maximum voltage of 1500VDC and 1000VAC between inputs. Do not
use on circuits exceeding the limit values specified in § 10.1
We recommend following the normal safety rules devised to protect the user against
dangerous currents and the instrument against incorrect use.
Only the accessories provided together with the instrument will guarantee safety
standards. They must be in good conditions and replaced with identical models, when
necessary.
Make sure that batteries are correctly installed.
Before connecting the measuring cables to the circuit being measured, check that the
desired function has been selected.

PV-ISOTEST
EN - 4
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.
The symbol “ ” indicates a full charge level of the internal batteries.
When battery charge decreases to a minimum level, the symbol “ ”
appears on the display. In this case, stop testing and replace the batteries
according to the indications given in § 9.2. 9.2
The instrument is capable of keeping data stored even without
batteries.
1.3. AFTER USE
When measurements are complete, switch off the instrument by pressing and holding the
ON/OFF key for some seconds. If the instrument is not to be used for a long time, remove
the batteries and follow the instructions given in § 3.3.
1.4. DEFINITION OF MEASUREMENT (OVERVOLTAGE) CATEGORY
Standard “IEC/EN61010-1: 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:
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.

PV-ISOTEST
EN - 5
2. GENERAL DESCRIPTION
2.1. FOREWORD
This instrument has been designed to carry out safety tests on photovoltaic (PV)
modules/strings in order to verify the parameters declared by the manufacturer. In addition,
this instrument measures insulation/continuity on PV modules/strings/fields.
2.2. INSTRUMENT FUNCTIONS
The instrument has the following features:
Continuity test of protective conductors (RPE)
Test with test current > 200mA in compliance with standards IEC/EN62446-1,
IEC/EN61557-4.
Manual calibration of measuring cables.
Measurement of insulation resistance on PV modules/strings (M)
Test voltages of 250V, 500V, 1000V, 1500VDC in compliance with standards
IEC/EN62446-1,IEC/EN61557-2
2 available measuring modes
DUAL Measurement in a sequence of the insulation between the string's positive
pole (+) and PE and between the string's negative pole and PE.
TMR single timed measurement between the string's negative pole and PE.
GFL (Ground Fault Locator) function to search for positions with a low insulation
among the modules of a PV string (see § 6.3).
The instrument is provided with backlit display, internal contrast adjustment and a HELP
key able to give a valid help to the operator while connecting the instrument to the
installation. An Auto Power OFF function, which can also be deactivated, is available after
approx. 5 minutes idleness.

PV-ISOTEST
EN - 6
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 checking it to detect any damage possibly suffered
during transport. In case anomalies are found, immediately contact the dealer. We also
recommend checking that the packaging contains all components indicated in § 10.4. In
case of discrepancy, please contact the Dealer. In case the instrument should be returned,
please follow the instructions given in § . 12
3.2. INSTRUMENT POWER SUPPLY
The instrument is battery supplied. For battery type and life, see § Errore. L'origine
riferimento non è stata trovata..
The symbol “ ” indicates a full charge level of the internal batteries. When battery charge
decreases to a minimum level, the symbol “ ” appears on the display. In this case, stop
testing and replace the batteries according to the indications given in § 9.2.
The instrument is capable of keeping data stored even without batteries.
The instrument is provided with advanced algorithms to maximize the batteries life. Long
pressing the key HELP/ activates the display's backlight adjustment. A frequent use of
backlighting reduces the batteries life.
3.3. 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 §
10.3).

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EN - 7
4. NOMENCLATURE
4.1. DESCRIPTION OF THE INSTRUMENT
CAPTION:
1. Inputs
2. LCD display
3. Keys
,,,, SAVE/ENTER
4. Compartment of connector for optical/USB
cable
5. Key GO/STOP
6. Key HELP/
7. Key ESC/MENU
8. Key ON/OFF
Fig. 1: Description of the front part of the instrument
CAPTION:
1. Inputs P, N, E, C
Fig. 2: Description of the upper part of the instrument
CAPTION:
1. Connector for connecting optically
insulated optical/USB output cable
Fig. 3: Description of the instrument’s side

PV-ISOTEST
EN - 8
4.2. KEYBOARD DESCRIPTION
The keyboard includes the following keys:
ON/OFF key to switch on/off the instrument
ESC key to exit the selected menu without confirming
MENU key to go back to the instrument's general menu at any time
Keys to move the cursor within the various screens in order to select
programming parameters
SAVE/ENTER key to save internal parameters and the results of measurements
(SAVE) and to select the desired functions from the menu (ENTER)
GO key to start measuring
STOP key to stop measuring
HELP key to access the help on line and display, for each selected function, possible
connections between the instrument and the system
Key (long pressing) to adjust the display's backlight
4.3. DISPLAY DESCRIPTION
The display is a graphic module with a resolution of 128 x 128 dots. The displays first line
indicates the systems date/time and contains the battery charge indicator. At the bottom of
the display, the active mode is shown.
4.4. INITIAL SCREEN
When switching on the instrument, the initial screen appears
for a few seconds. It shows:
The instrument model (PV-ISOTEST)
The manufacturer’s name
The serial number (SN:) of the instrument
The firmware version (FW:) in the instrument's memory
The date of the last instrument calibration (Calibration
date:)
PV-ISOTEST
HT
SN: 20345678
HW: 1.00
FW: 1.02
Calibration date:
07/09/2020
After a few seconds, the instrument switches to the last function selected.

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EN - 9
5. GENERAL MENU
Pressing the ESC/MENU key in any condition of the
instrument displays the general menu screen, in which the
instrument may be set, the saved measures can be displayed
and the desired measuring function can be selected.
Use the cursor to select one of the options and confirm with
ENTER to access the desired function.
MENU 14/09 -17:34
DMM : Voltage
M: Insulation:
GFL Find Insul. fault
RPE : Continuity
SET : Settings
MEM : Data saved
PC : Data transfer
5.1. SET – INSTRUMENT SETTINGS
Position the cursor onto SET by using the arrow keys (,)
and confirm with ENTER. The display shows the screen
which lists the different settings of the instrument.
Settings will be maintained also after switching off the
instrument.
SET 14/09 -17:34
Language
Date and time
General settings
Information
5.1.1. Language
Move the cursor to Language by using the arrow keys (,)
and confirm with ENTER. The instrument shows the screen
which allows setting the system language.
Select the desired option by using the arrow keys (,).
Press the ENTER key to confirm or the ESC key to go back
to the previous screen.
SET 14/09 – 17:34
English
Italian
Español
Deutsch
Français
Portuguese
5.1.2. Date and time
1. Position the cursor onto “Data Time” by using the arrow
keys (,) and confirm with ENTER.
2. The display shows the screen which allows setting the
system’s date/time both in the European (EU) and in the
USA (US) format.
3. Set the desired measuring units by means of the arrow
keys (, ).
4. Press the SAVE key to save the settings made; the
message “Data saved” will be displayed for a few
seconds. Press the ESC/MENU key to exit without saving
and go back to the previous screen.
SET 14/09 – 17:34
Format :EU 
Year
Month
Day
Hour
Minute
:20 
:09 
:14 
:17 
:34 

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EN - 10
5.1.3. General
Move the cursor to General by using the arrow keys (,)
and confirm with ENTER. The instrument shows the screen
which allows activating/deactivating the the Auto Power Off
function and the key tone.
Select the desired option by using the arrow keys (,).
Press the ENTER key to confirm or the ESC key to go back to
the previous screen.
SET 15/10 – 18:04
AutoPowerOff :OFF 
Keys beep :OFF 
5.1.4. Info
Move the cursor to Info by using the arrow keys (,) and
confirm with ENTER.
The instrument shows the initial screen as indicated in the
screen to the side.
Press the ESC key to go back to the main menu.
15/10 – 18:04
PV-ISOTEST
HT
S/N: 20345678
HW: 1.00
FW: 1.02
Calibration date:
07/09/2020

PV-ISOTEST
EN - 11
6. OPERATING INSTRUCTIONS
6.1. RPE – CONTINUITY MEASUREMENT ON MODULES/STRINGS/PV FIELDS
The purpose of this measurement is performing a continuity test of the protective and
equipotential conductors (e.g.: from rod to earth and connected foreign earth) and earth
rods of SPDs on PV installations. The test must be carried out using a test current >
200mA according to the prescriptions of IEC/EN62446-1 and IEC/EN61557-4 guidelines.
6.1.1. Calibration of measuring cables
1. Position the cursor onto RPE by using the arrow keys
(,) and confirm with ENTER. The display shows the
following screen:
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
STD 2.00- - - 
MODE Lim. ><
2. Use the arrow keys or and select the position “><”.
The display shows the screen to the side.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
STD 2.00- - - 
MODE Lim. ><
3. Connect the measuring cables to each other as shown in Fig. 4.
Fig. 4: Compensation of the measuring cables resistance

PV-ISOTEST
EN - 12
4. Use the arrow keys or and select the position “><”.
The display shows the screen to the side.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
STD 2.00- - - 
MODE Lim. ><
5. Press the GO/STOP key to start calibration. Messages
“Measuring…” followed by “Verification” and “Zeroing” are
shown in a sequence on the display.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
Measuring…
STD 2.00- - - 
MODE Lim. ><
6.
A
t the end of the compensation procedure, in case the
measured resistance value is ≤5, the instrument emits a
double tone to signal the positive result of the test and
displays the value of the compensated resistance of the
cables, which will be subtracted from all the subsequent
continuity measurements, at the bottom on the right side
of the display.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
STD 2.000.06 
MODE Lim. ><

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EN - 13
6.1.2. Carrying out continuity measurements in Standard (STD) mode
1. Position the cursor onto RPE by using the arrow keys
(,) and confirm with ENTER. The display shows the
following screen. The symbol “STD” is shown on the
display.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
STD 2.00- - - 
MODE Lim. ><
2. Use the arrow keys or and select the position
““Lim.”. The display shows the screen to the side.
3. Use the arrow keys (,) to set the limit reference
threshold for continuity measurement, which can be
selected in a range between 0.019.99in steps of
0.01(please remember that guidelines does not
establish a limit value or resistance and typical values are
approx. 1or 2).
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
STD 2.00- - - 
MODE Lim. ><
4. Carry out the initial calibration of the measuring cables (see § 6.1.1).
5. Connect the instrument to the PV module/string being tested and to the main earth
node of the system as shown in Fig. 5.
CAPTION:
E: Green cable
C: Blue cable
1. PV module/string
2. Main system earthing
3. Earthed metal structure
in the system
Fig. 5: Connection of meter for continuity measurement on structures of the PV installation
CAUTION
Upon pressing the GO/STOP key, different error messages can be displayed
by the instrument (see § 6.1.4) and, therefore, the test cannot be started.
Check and eliminate, if possible, the problem causing the error message
before going on with the test.

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EN - 14
6. Press the GO/STOP key to start the test. In case no error
conditions occur, the instrument displays the message
“Measuring…” as shown in the screen to the side.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
Measuring…
STD 2.000.06 
MODE Lim. ><
7.
A
t the end of measurement, the instrument provides the
value of resistance of the object being tested. If the result
is lower than the set maximum limit value, the instrument
shows the message “OK” (value lower or equal to the set
limit threshold), otherwise it displays the message “NO
OK” (value higher than the set limit threshold) as shown
in the screen to the side.
8. Press the SAVE key to store the test result in the
instrument’s memory (see § 7.1) or the ESC/MENU key to
exit the screen without saving and go back to the main
measuring screen.
RPE 15/10 – 18:04
R 0.23 
Itest 210 mA
OK
STD 2.000.06 
MODE Lim. ><

PV-ISOTEST
EN - 15
6.1.3. Carrying out continuity measurements in Timer (TMR) mode
1. Position the cursor onto RPE by using the arrow keys
(,) and confirm with ENTER. The display shows the
following screen.
2. Use the arrow keys (,) to select the Timer mode. The
symbol “TMR” is shown on the display.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
T - - - s
TMR 2.0012s - - - 
MODE Lim. Time ><
3. Use the arrow keys or and select the position “Lim.”.
The display shows the screen to the side.
4. Use the arrow keys (,) to set the limit reference
threshold for continuity measurement, which can be
selected in a range between 0.019.99in steps of
0.01(please remember that guidelines does not
establish a limit value or resistance and typical values are
approx. 1or 2).
RPE 15/10 – 6:04 PM
R - - - 
Itest - - - mA
T - - - s
TMR 2.0012s - - - 
MODE Lim. Time ><
5. Use the arrow keys or and select the position
“Time”. The display shows the screen to the side.
6. Use the arrow keys (,) to set the duration of
continuity measurement (Timer), which can be selected
in a range between 3s 99s in steps of 3s.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
T - - - s
TMR 2.0012s - - - 
MODE Lim. Time ><
7. Carry out the initial calibration of the measuring cables (see § 6.1.1).
8. Connect the instrument to the PV module/string being tested and to the main earth
node of the system as shown in Fig. 5.
CAUTION
Upon pressing the GO/STOP key, different error messages can be displayed
by the instrument (see § 6.1.4) and, therefore, the test cannot be started.
Check and eliminate, if possible, the problem causing the error message
before going on with the test.

PV-ISOTEST
EN - 16
9. Press the GO/STOP key to start the test. In case no error
conditions occur, the instrument starts a series of
continuous measurements for the entire duration of the
set Timer, emitting a short sound every 3s, and
showing alternatively the messages “Measuring…” and
“Please wait…” as shown in the screen to the side. In this
way, the operator can move from one point to another of
the place in which measurement is being carried out.
RPE 15/10 – 18:04
R 0.23 
Itest 209 mA
T 11 S
Please wait…
STD 2.0012s 0.06 
MODE Lim. Time ><
10.At the end of measurement, the instrument provides the
maximum value among all those of the partial
measurements carried out. If the result is lower than the
set maximum limit value, the instrument shows the
message “OK” (value lower or equal to the set limit
threshold), otherwise it displays the message “NO OK”
(value higher than the set limit threshold) as shown in the
screen to the side.
11.Press the SAVE key to store the test result in the
instrument’s memory (see § 7.1) or the ESC/MENU key to
exit the screen without saving and go back to the main
measuring screen.
RPE 15/10 – 6:04 PM
R 0.54 
Itest 209 mA
T 0 S
OK
STD 2.0012s 0.06 
MODE Lim. Time ><

PV-ISOTEST
EN - 17
6.1.4. Anomalous situations
1. To zero the value of compensated resistance, carry out a
new compensation procedure with a resistance higher
than 5as, for example, with open leads. The message
“Zero Reset” appears on the display.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
Zero Reset
STD 2.00- - - 
MODE Lim. ><
2. In case the instrument detects a voltage higher than 3V
at its terminals E and C, it does not carry out the test,
gives out a long sound and displays the message “V.Input
> 3V”.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
V.Input > 3V
STD 2.00- - - 
MODE Lim. ><
3. In case the instrument detects that the calibrated
resistance is higher that the measured resistance, the
instrument gives out a long sound and displays the
message: “Zeroing NOT OK”
RPE 15/10 – 18:04
R 0.03 
Itest 212 mA
Zeroing NOT OK
STD 2.000.220 
MODE Lim. ><
4. In case the instrument detects a resistance higher than
5at its terminals, it gives out a long sound, zeroes the
compensated value and displays the message “Zero
Reset”.
RPE 15/10 – 18:04
R >4.99 
Itest 49 mA
Zero Reset
STD 2.00- - - 
MODE Lim. ><
5. If the instrument detects a calibrated resistance higher
than measured resistance (e.g. by using test cables
different from the supplied ones) at its terminals, it gives
out a long sound and displays a screen like the one to the
side. Perform a calibration reset with open terminals and
start a new calibration.
RPE 15/10 – 18:04
R - - - 
Itest - - - mA
Rcal > Rmis
STD 2.00- - - 
MODE Lim. ><

PV-ISOTEST
EN - 18
6.2. M– MEASUREMENT OF INSULATION ON PV MODULES/STRINGS/FIELDS
The purpose of this function is measuring the insulation resistance of the active conductors
of PV modules, strings and fields according to the prescriptions of IEC/EN62446-1 and
IECEN61557-2 guidelines, with no need to use an external switch to short-circuit the
positive and negative terminals.
CAUTION
The insulation measurement can be performed on a single module, on a
string or on a system consisting of several strings connected in parallel
If the module/string/system has a pole connected to ground, this connection
must be temporarily disconnected
In compliance with IEC/EN62446-1, the test voltage Vtest must be ≥rated
voltage of the system
The IEC/EN62446-1 guideline sets 1Mas the minimum insulation
resistance limit value for systems with rated voltage higher than 120V
Disconnect the string/system from the inverter and any dischargers
It is advisable to carry out the insulation measurement upstream of any
blocking diodes
In general, the instrument measures insulation in the following modes:
DUAL mode the instrument measures insulation in a sequence between the positive
pole (+) and the PE reference and between the negative pole (-) and the PE reference
of PV modules, strings and fields.
TMR mode the instrument measures continuously (with a max duration of 999s)
between terminal “N” and PE reference, displaying the minimum resistance value
obtained at the end of the selected time. In this way, the instrument also calculates the
DAR (Dielectric Absorption Ratio) and PI (Polarization Index) parameters if the duration
of the test is adequate for the calculation of the above parameters.
6.2.1. Measuring insulation – DUAL mode
1. Position the cursor onto Mby using the arrow keys
(,) and confirm with ENTER. The display shows the
screen to the side. By using the arrow keys (,) again,
select the “DUAL” measuring mode, in position “MODE”.
M15/10 – 18:04
(+) (-)
Vtest - - - - - - V
Rins - - - - - - M
Rp - - - M
VPN VPE VNE
0V 0V 0V
DUAL 1500V 1.00M
MODE Vtest. Lim.
2. Use the arrow keys or and select the position
“Vtest” to set the test voltage.
3. Use the arrow keys (,) to select one of the following
test voltages (Vnom): 250, 500, 1000, 1500VDC. Please
note that in compliance with IEC/EN62446-1 the test
voltage Vtest must be ≥rated voltage of the system
M15/10 – 18:04
(+) (-)
Vtest - - - - - - V
Rins - - - - - - M
Rp - - - M
VPN VPE VNE
0V 0V 0V
DUAL 1500V 1.00M
MODE Vtest. Lim.

PV-ISOTEST
EN - 19
4. Use the arrow keys or and select the position “Lim.”.
The display shows the screen to the side.
5. Use the arrow keys (,) to set the minimum limit
threshold for insulation measurement, which can be
selected among the values 0.05, 0.10, 0.23, 0.25, 0.50,
1.00, 50M.Please note that IEC/EN62446-1 guideline
sets 1Mas the minimum insulation resistance limit
value for systems with rated voltage higher than 120V
M15/10 – 18:04
(+) (-)
Vtest - - - - - - V
Rins - - - - - - M
Rp - - - M
VPN VPE VNE
0V 0V 0V
DUAL 1500V 1.00M
MODE Vtest. Lim.
6. Connect the instrument to the PV string to be tested as shown in Fig. 6. The test can
also be performed on several strings in parallel with each other. Remember that any
surge arresters connected to the string cables must be disconnected and that it is
advisable to measure upstream of any blocking diodes
Fig. 6: Instrument connection for insulation measurement in DUAL mode
CAUTION
Upon pressing the GO/STOP key, different error messages can be displayed
by the instrument (see § 6.2.3) and, therefore, the test cannot be started.
Check and eliminate, if possible, the problem causing the error message
before going on with the test.
7. Press and hold the GO/STOP key for 2s in order to
start the test. In case no error conditions occur, the
instrument displays the message “Measuring…” as
shown in the screen to the side. In field “Vtest”, the real
test voltage generated by the instrument is shown. The
duration of the test can be depending on the
presence or absence of parasitic capacities present
M15/10 – 18:04
(+) (-)
Vtest - - - - - - V
Rins - - - - - - M
Rp - - - M
VPN VPE VNE
1480V -750V 748V
Measuring…
DUAL 1500V 1.00M
MODE Vtest. Lim.