UNAOHM I-V Tracer 935 User manual

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I-V Tracer 935
USER’S MANUAL
UNAOHM S.r.l. - Via G. Di Vittorio 49 - 20068 Peschiera Borromeo (MI) Italia
Tel. [phone] - Fax [phone] - Web: www.unaohm.it - E-mail: [e-mail]

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1.
WARNINGS
Thank you for purchasing an I-V TRACER 935. For best results from your instrument:
 read these operating instructions carefully,
 comply with the precautions for use.
Meanings of the symbols on the instrument:
WARNING, risk of DANGER! The operator must refer to these instructions whenever this danger symbol
appears.
The CE marking indicates conformity with European directives, in particular LVD and EMC.
Equipment protected by double insulation.
The rubbish bin with a line through it indicates that, in the European Union, the product must undergo selective
disposal in compliance with Directive WEEE 2002/96/EC. This equipment must not be treated as household
waste.
USB port.

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2.
PRECAUTIONS FOR USE
This instrument and its accessories comply with safety standards IEC 61010-1, IEC 61010-031, and IEC 61010-2-032
for voltages of 600V in category III, or 1000V in category II, at an altitude of less than 2000m, indoors, with a degree of
pollution of not more than 2.
Failure to observe the safety instructions may result in electric shock, fire, explosion, and destruction of the instrument
and of the installations.
 The operator and/or the responsible authority must carefully read and clearly understand the various precautions
to be taken in use. Sound knowledge and a keen awareness of electrical hazards are essential when using this
instrument.
 If you use this instrument other than as specified, the protection it provides may be compromised, thereby
endangering you.
 The safety of any system incorporating this instrument is the responsibility of the person who assembles the
integrated system.
 For your safety, use only the cables and accessories supplied with the instrument: they comply with IEC 61010-
031 (2002). When the sensors or accessories used are of a lower category than the instrument, the lower rating
must be applied to the entire system.
 Before each use, make sure that the cables, junction boxes, and accessories are in perfect working condition.
Any cable, sensor, or accessory of which the insulation is damaged (even partially) must be set aside for repair
or eliminated.
 Do not use mains power when making measurements. Mains power may be used only to recharge the internal
batteries, with the instrument switched off.
 Respect the environmental conditions.
 Use personal protection equipment systematically.
 Never use it on systems of which the voltage or category is higher than that indicated.
 For replacement of the internal battery, contact an authorized service center only. These components have
specific safety devices; using non-original spare parts could cause serious damage to persons or property.
 Respect the limits of the physical protections of the accessories and sensors. Do not place your hands on
unused terminals.
 All troubleshooting and metrological checks must be performed by competent and accredited personnel.
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NOTES CONCERNING THIS MANUAL
 The information in this manual is subject to change without prior notice;
 Although this manual has been written with the utmost care, please contact the manufacturer should you have
any comments, opinions or product-related questions;
 Make sure you fully understand the pre-requisites for use of the product, such as its technical characteristics
and hardware and the software limitations affecting its use. We decline all responsibility for damage resulting
from improper use of the product;
 Reproduction of this manual, in full or in part, without written permission from our company, is prohibited.
• The maximum voltage between the inputs is 1000VDC. Do not measure voltage exceeding the limits in this manual.
• The maximum current the instrument tolerates is 10ADC. Do not carry out tests on FV module strings connected in
parallel.
• Never test FV modules or strings connected to the DC/AC converter.

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INDEX
1. WARNINGS ......................................................................................................................................... 2
2. PRECAUTIONS FOR USE ...................................................................................................................3
3. NOTES CONCERNING THIS MANUAL .............................................................................................. 3
4. INTRODUCTION .................................................................................................................................. 5
5. DESCRIPTION OF CONNECTIONS AND CONTROLS ..................................................................... 6
6. DISPLAY UNIT ..................................................................................................................................... 7
7. POWER SUPPLY ................................................................................................................................ 7
7.1. Battery life ........................................................................................................................................ 7
7.2. Charging the batteries.......................................................................................................................7
7.3. Mains power supply unit .................................................................................................................. 7
8. ON/OFF SWITCH ................................................................................................................................ 7
9. IMPORTANT NOTE FOR USE ............................................................................................................ 8
10. DESCRIPTION OF THE MENUS ........................................................................................................ 8
10.1. System ............................................................................................................................................. 8
10.2. Module Archive ................................................................................................................................ 9
10.3. Company Archive ...........................................................................................................................10
10.4. Measurements Archive ................................................................................................................... 11
10.5. Installations Archive ........................................................................................................................ 11
10.6. USB............................................................................................................................................... 12
10.6.1. USB-Bluetooth adapter ......................................................................................................... 12
10.6.2. USB pen drive ....................................................................................................................... 12
11. MAKING MEASUREMENTS .............................................................................................................. 14
11.1. Electrical connections: .................................................................................................................... 14
11.2. Remote Unit ................................................................................................................................... 15
11.3. Module or String..............................................................................................................................15
11.3.1. Interpreting the measurement results………………………………………………………….. 21
11.4. Other functions ............................................................................................................................... 22
11.4.1. "FS" (full scale) function ........................................................................................................ 22
11.4.2. Zoom Function ...................................................................................................................... 22
12. TECHNICAL CHARACTERISTICS ..................................................................................................... 24
12.1. Reference conditions ...................................................................................................................... 24
12.2. Specifications ................................................................................................................................. 24
12.3. Environmental conditions ............................................................................................................... 24
12.4. Construction specifications ............................................................................................................ 25
12.5. Electromagnetic compatibility ........................................................................................................ 25
12.6. Mechanical protection .................................................................................................................... 25
13. I-V Tracer 935 PC SOFTWARE ............................................................................................................ 26
13.1 General information ........................................................................................................................ 26
13.2 Installation ...................................................................................................................................... 26
13.3 Using the program .......................................................................................................................... 27
13. MAINTENANCE ................................................................................................................................. 36
13.1. Cleaning ......................................................................................................................................... 36
13.2. Metrological check .......................................................................................................................... 36
13.3. Repair ............................................................................................................................................ 36
14. WARRANTY ....................................................................................................................................... 37
15. TO ORDER ........................................................................................................................................ 38
15.1. Optional accessories ...................................................................................................................... 38
15.2. Spare parts .................................................................................................................................... 38
16. LIST OF POP-UP DISPLAY MESSAGES ..........................................................................................39

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4.
INTRODUCTION
Photovoltaic systems are in two main parts:
A photovoltaic generator comprising one or more strings of photovoltaic panels that generate a direct current.
An inverter that converts the direct current generated by the panel into alternating current so it can be used in the grid.
The I-V TRACER 935 has two measurement inputs, one for measuring voltage (VDC) and one for measuring current (I-
DC). Measurements can be made on a single panel or on a string of panels (the latter measure is not provided for in the
standard).
There are also inputs for a pyranometer sensor and a temperature probe.
The temperature probe input accepts both the ambient temperature probe and the contact probe used to measure the
temperature of the photovoltaic panels.
The I-V TRACER 935 instrument also lets you enter a percentage of "degradation" and the age (years) of the PV module
or of the PV string, further improving the accuracy of the test results.
To make the instrument easier to use in difficult conditions, an UT925 REMOTE UNIT accessory is available to allow
wireless connection of the pyranometer sensor and the temperature probe; the sensor measurements are transmitted
to the instrument by BLUETOOTH, via a pair of adapters connected to the respective communication ports.
The main measurements made are:
 measurement of solar radiation by pyranometer (up to 2000W/m²)
 measurement of the ambient temperature or panel temperature by Pt100 sensor (up to 120°C)
 possibility of measuring both single panels and strings of panels
 measurement of the no-load voltage and the MPP voltage (up to 1000 VDC)
 measurement of the short-circuit current and the MPP current (up to 10 ADC)
 graphic representation of the I-V curve with marker at the MPP.
 graphic representation of the power curve with marker at the MPP.
 comparison of the measurements with the panel nameplate data and indication of the result:
OK/NO
 calculation of the efficiency of the solar panels and display of the difference between the nominal value
and the measured value
 measurement of the series resistance, Rs, in compliance with the requirements of standard EN60981
The I-V TRACER 935 is a measuring instrument designed and built to meet the needs of technicians doing
troubleshooting or maintenance work on the photovoltaic generator or module in conformity to the IEC/EN 60891
standard.
All the electrical data measured in OPC operating conditions are “transferred” to radiation STC standard conditions equal
to 1000W/m2 and module temperature of 25°C applying the calculation formulas in conformity to the IEC/EN
60891standard.
The user may request the comparison (DPmax) between the maximum power (Pmax) stated by the manufacturer and
the maximum power measured during the test (OPC), transferred to the STC standard conditions (as stipulated in the
IEC/EN 60891 standard).
If the comparison value is within the manufacturer’s stated tolerance, the test result is "OK"; otherwise, it is "NO".
N.B.: the IEC/EN 60891 standard indicates the procedures for transferring the values measured under real OPC
operating conditions to the reference standard STC conditions for a single module. Consequently, a negative result for
a measurement test on one string of modules could mean that every single module has to be measured in order to
identify the defective module or modules in the string.

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5.
DESCRIPTION OF CONNECTIONS AND CONTROLS
1) Temperature probe input
2) Pyranometer input
3) USB 2.0 port
4) External power supply input (15V DC; maximum current consumption 2A)
5) 4.3" colour "touch-screen" LCD Monitor
6) Input for voltage measurements
7) Input for current measurements
8) Multi-function keypad including the following keys:
▲ : "up" arrow key
► :"right" arrow key
OK: button to confirm selection
◄ :"left" arrow key
▼ :"down" arrow key
On/off key
Return to main menu key
BATT Ch LED (active only with external power supply connected)
lit while battery is charging, which takes place ONLY when the instrument is Off
FULL CH LED INDICATOR (active only with external power supply connected)
lit when the internal batteries have reached full charge

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6.
DISPLAY UNIT
The I-V TRACER 935 has a 4.3" colour touch-screen LCD display that displays function access icons, menus, and
graphs of the I-V curves of the panel or string of panels measured.
Main screen Graph Screen
7.
POWER SUPPLY
7.1. Battery life
The battery icon in the lower right part of the display indicates the battery's charge status. The number of bars in the
icon is proportional to the charge level.
Battery fully charged. Remaining life approx. 12 hours
Battery semi-charged. Remaining life approx. 50 minutes
Battery low (blinking symbol). Remaining life approx. 10 minutes
7.2. Charging the batteries
The battery is charged with the INSTRUMENT OFF, using the power supply unit supplied with the instrument, which is
connected to the dedicated jack.
It is recommended that only the power supply unit provided with the instrument be used. This type of power supply unit
is specific to the instrument and ensures electrical safety.
If the battery is fully discharged, the charging time is approx. 5 hours.
7.3. Mains power supply unit
The mains power unit accepts voltages ranging from 90V to 260V-50Hz. The protecting fuses are inside the mains
power unit and are not accessible.
NOTE: If the fuses blow, do not replace them, but send the power supply unit to the service centre for inspection.
ATTENTION: use only the mains power unit to charge the internal batteries.
Before using the instrument to make measurements, make sure that the mains power unit is disconnected.
8. ON/OFF SWITCH
To switch the instrument On, press the button and hold it down for approx. 3 seconds
NOTE: If, when the key is released after starting up, the instrument switches itself off, the batteries are not sufficiently
charged. Charge the batteries before use.
To switch the instrument Off, press the button and hold it down for approx. 3 seconds

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9. IMPORTANT NOTE FOR USE
To enter alphanumeric characters in one of the fields listed in the menus or in specific functions, use the keypad,
opened by touching the screen that corresponds to the desired field.
To switch the keypad from numeric to alphabetical mode, press the (ABC) key in the lower left corner.
To switch the keypad from alphabetical to numeric mode, press the (.?123) key in the lower left corner.
Keypad in numeric mode Keypad in alphabetical mode
When it is impossible to use the TOUCH-SCREEN, the keypad on the front panel can be used to select icons and
control keys. Use the arrow keys to select the desired icon or control key, then confirm by pressing the OK key.
10.
DESCRIPTION OF THE MENUS
10.1. System
If this icon is selected, a window containing the instructions and system settings opens as described below.
Before browsing this menu, please wait a few seconds until the Power Version Number is displayed.
Serial number: indication of the instrument's serial number.
SW Version: indication of the instrument's firmware version (upgradable through the "USB" menu)
Power Version: indicates the version of the instrument's measuring software.
Display: The date and time can be displayed at all times in the top bar of the display; pressing the ▼ key opens a
window in which you can select one of the following conditions:
Local: the date and time are not displayed.
Date-Time: the current date and time are displayed simultaneously.
Date: only the current date is displayed.
Time: only the current time is displayed.
Setting the date and time: the current date and time are displayed in their respective fields; to edit the date/time,
select the value to be changed using the ▲ or ▼ key.
Press the "Apply" button to confirm the new settings and exit from the menu.
Temperature probe: press the ▼ key to open probe type selection window:
Module: the measurements are made with allowance for the temperature of the photovoltaic module.
Ambient temperature: the measurements are made with allowance for the ambient temperature.
Sens. Pyra (mV/kW/m2): the pyranometer sensitivity value is displayed in the corresponding window. Because of a
change of unit, this value is 1,000 times the value marked on the pyranometer (i.e. 0.01490mV/Wm-2 x 1.000 =
14.90mV/kW/m2). If the assigned does not correspond to the pyranometer used or if the pyranometer is replaced, select
this window and enter a new value using the keypad displayed. Then press "Apply" followed by "Invio" ("Enter") to
confirm the new setting and close the function.

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If the value set does not match that of the pyranometer being used, or if the pyranometer is replaced, select the window
on the screen, use the instrument's keypad to configure the new value, and when the change has been made click on
"ENTER" to confirm the setting and exit from the field.
Minimum radiation: can be used to set the minimum solar radiation value in W/m2, adjustable from 1 to 1,000W/m2,
used as reference by the instrument during a measurement.
Please always check that the value set is consistent with the measurement you want to make.
We recommend making measurements with a solar radiation value ≥700W/m2 in compliance with standard
IEC/EN60981.
Remote Unit: If the ▼ button is pressed, the remote unit activation window opens for selection of the type of
connection between the remote unit and the I-V Tracer 935. Possible choices are:
Local, the probes are connected without the use of a remote unit.
RS-232 Serial Adapter, the BLUETOOTH module is connected to the instrument's USB port by an
RS232-USB adapter.
Bluetooth Adapter, the connection is via a USB-BLUETOOTH adapter module. When this item is selected, the
following two fields are activated for the following settings:
Bluetooth Address (MAC), if the corresponding field is selected, a keypad opens for entry of the "MAC" number of
the Bluetooth adapter used on the remote unit with which you want to communicate.
NOTE: For the Bluetooth devices of the instrument and the remote unit to be able to communicate, the MAC number
of the Bluetooth adapter used on the instrument must be set in the Bluetooth device used on the remote unit.
The PIN code setting of this device must not be activated.
To configure the device used on the remote unit, follow the instructions provided in the remote unit's manual.
Device name: this can be used to enter a name for the Bluetooth adapter used for the instrument; this is optional.
Brightness: click on the associated numeric value to modify it if necessary
Language: press the ▼ key to open the language selection window. Touch the desired language on the screen to
confirm the selection and exit.
Memory used: this displays the percentage of the instrument's memory occupied by the data entered and the stored
measurements.
Note that the available memory of the instrument is 84 MBytes.
10.2. Module Archive
Selecting this icon opens a window with the following functions:
New Module: Selecting this icon activates a function allowing entry of the model and plate data of a panel not present
in the pre-loaded list. If a new brand must be entered, exit by selecting "Exit", then select the "Edit Brand" icon.
Edit Brand: Selecting this icon opens a window containing a list of the brands present; select the "enter new brand" line
if you want to add a brand not present in the list. Select the window below the list to enter the new name, then click on
"SAVE" to confirm, or "Exit" to cancel the operation.
Working in the same way as described above, you can select and then edit the name of a brand already present.
Find: selecting this icon opens a window that lets you search the list of panels in memory according to a selection
criterion based on their electrical characteristics. Completing one or more of the fields for the main electrical
characteristics of the panels and pressing the "Search" button displays a list of panels matching the values entered.
This function can be used, for example, for a quick check of the brand and model of panels that have the selected
characteristics.
Edit Module: when this function is used – once the brand has been selected – it is possible to edit and update the
model and electrical characteristics of the listed panels
List: Selecting this icon opens a window displaying a list of the panels and their respective characteristics.
Delete: This function can be used to delete a brand from the list, or all panels that correspond to it, or a single panel. To
delete, select the brand and possibly the model; press "Delete Model" if you want to delete only the selected model,
"Delete Brand" to delete the brand and all of its contents.
Press the "Exit" button to return to the previous menu.

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Module Archive menu window New Module data entry window
The table below indicates ranges of values for the characteristic parameters of the panels that are entered when a
New Module record is created in the database.
Symbol Description Measurement
unit Range
Pmax Maximum power of the module (W) 1.00 to 1000.0
Vmpp Voltage at maximum power point (V) 1.00 to 200.0
Voc No-load voltage (V) 1.00 to 200.0
Type Type of silicone in the cells
Monocrystalline
Polycrystalline
Thin Film
Amorphous
Micromorph
Beta
Voc temperature coefficient
(%/°C)
-
1.00 to
-
0.0001
Toll
–
Negative tolerance of P
max
stated by the PV module manufacturer
(%)
0 to
-
50
NOCT
Nominal operating temperature of the cell
(°C)
0 to 100
Impp Current at maximum power point (A) 0.2 to 10.00
Isc Short-circuit current (A) 0.2 to 10.00
Alpha
I
sc
temperature coefficient
(%/°C)
-
0.200 to + 0.200
Gamma
P
max
temperature coefficient
(%°C)
-
1.00 to
-
0.01
Toll +
Positive tolerance of P
max
stated by the PV module manufacturer
(%)
0 to +50
10.3. Company Archive
Select this icon to access the client record management, look-up, and deletion functions via the following menus:
New: select this icon to enter a new record. Click in the desired field to open the keypad; when you have finished
typing, confirm your entry by pressing "ENTER".
Note: the Tax code field must be filled in.
List: press this icon to open the list of all stored records; to view the details of a record, click on the corresponding line
and press "Open". To view the characteristics of the installations associated with the record, select the installations and
press "Display".
Edit: click on this icon to access the Edit record function; to make a change, select the desired record in the "Surname
- Company Name" field(s) and press the "Edit" button. Select the field to be edited, enter the changes, and confirm by
pressing "ENTER".
Delete: select this icon to open a list of stored records. Select the record you want to delete by highlighting it in the
"First name - Name" field and click on the "Delete" button to delete it from the memory.
Company Archive Windows Menu Window Company Details Window

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10.4. Measurements Archive
Press this icon to access all measurement archive management windows. The available functions are:
Modules: click on this icon, then on "List", to display the records of all measurements made on individual panels.
Strings: click on this icon, then on "List", to display the records of all measurements made on strings.
To view the graph of a measurement, for both modules and strings, select the desired measurement in the list by touching
the desired item on the screen, then select the "Graph" button. When viewing the graph, you can use the "FS" command
in the top right corner to switch to full screen graph display mode or to display both the graph and the command bar at
the bottom of the screen, with the following items:
Module or String: displays the electrical data measured.
Environment: displays the ambient temperature and radiation measurements.
Power: displays the OPC or STC power curve on the graph, depending on the selection made.
Exit: return to previous menu.
Delete: click on this icon after selecting "Panels" or "Strings" to enter Delete measurement record mode. To delete a
record, select the desired line and press "Delete"
Measurements Archive Windows
10.5. Installations Archive
Press this icon to access the installations archive in order to create, manage and if necessary, delete measurement
records. The available functions are:
New: select this icon to enter the new installation entry window.
When the field of an item is selected, the data entry keypad opens; when you have finished entering the data, confirm
by pressing the "ENTER" key. Repeat the same steps for each field to be completed.
List: press this icon to open the list of all stored installations; to view the details of an installation, click on the
corresponding line, then press "Open". To view the data of a plant associated with the installation, select the plant and
press "Display".
Edit: click on this icon to access the Edit installation function; to make a change, select the desired installation in the
"ID" field and press the "Edit" button. A keypad opens when the field to be edited is selected; enter the changes, then
confirm by pressing "ENTER".
Delete: selecting this icon opens a window from which the list of stored installations is accessed. Select the installation
you want to delete, highlighting it in the "ID" field, then click on the "Delete" button.
Installation Archive Menu Window Installation Data Entry Window

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10.6. USB
Select this icon to access the USB port management menu and its controls.
Main screen USB menu screen
The USB port can be used to control the following devices.
10.6.1. USB-Bluetooth adapter
this device allows the instrument to communicate with the "UT925 Remote Unit" to obtain the measurements from the
atmospheric probes. The instructions for adjusting the USB-BLUETOOTH ADAPTER are given in Chapter 10.1,
"System".
10.6.2. USB pen drive
USB memory is used to transfer archives (measurements or settings) from the instrument to the PC and vice versa. This
is done by selecting the "Copy to…" or "Copy from…" command; a window then appears on the screen for the selection
of the destination folder or the "source" folder.
"Copy from..." message box "Copy to..." message box
The "Copy to..." command corresponds to a transfer from the instrument onto the USB pen drive.
The "Copy from..." command corresponds to a transfer from the USB pen drive to the instrument.
The pen drive is also used to update the instrument's firmware. To carry out the update, make sure you have copied the
file with the "upg." extension to the USB key. Once the USB key connection is established, select "Update" in the menu;
a window in which to select the update file appears on the monitor. Select the file to be loaded, then click on "Confirm".
The progress bar displays the progress of the update; when it is complete, you are prompted to restart the instrument.
Press OK to finish the procedure.
File selection window Update progress bar window

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Restart command window
IMPORTANT NOTE: To ensure the correct operation of the USB devices, execute the following commands once the
USB key to be used has been inserted in the connector:
Connect: clicking on this command opens a window for confirmation of the connection between the instrument and the
device inserted in the port, USB-BLUETOOTH ADAPTER or USB PEN DRIVE. During the connection of the inserted
device, a connection progress indicator appears on the monitor.
Connection message box Connection progress window
Disconnect: select this command to start the "safe" disconnection of the connected device.
The disconnection progress bar appears on the monitor; once disconnection is complete, it is possible to disconnect
the device in use from the connector.
Disconnection progress window Disconnection complete message box

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11. MAKING MEASUREMENTS
Before making measurements, make sure that the pyranometer and the temperature probe have been connected, as
follows:
PYRANOMETER: the pyranometer must be placed on the same level as the modules to be tested; also make sure
that there are no shadows.
Attach the pyranometer directly to the PV module frame or to the main structure using the metallic accessory supplied
with the pyranometer (take care to avoid further shade by improper positioning of the pyranometer).
Make sure the angle between the sun’s ray and the module’s surface is as close as possible to 90°, the ideal angle for
obtaining excellent reliable results. If need be repeat the measurements at other times of the day.
Plug the connector directly into the instrument or the Remote Unit (if used).
AMBIENT TEMPERATURE PROBE: the temperature probe must be placed in a shaded area that is adequately
ventilated and near the modules.
Plug the connector directly into the instrument or the Remote Unit (if used).
PANEL TEMPERATURE PROBE: the temperature probe must be positioned on the back of the panel aligned to a
cell; if you are measuring a string of panels, place the probe on a panel in the middle of the string.
Plug the connector directly into the instrument or the Remote Unit (if used).
11.1. Electrical connections:
The inputs for the V-DC voltage and I-DC current measurements are on the front panel.
Connect cables in parallel from the positive terminals of the instrument to the positive terminal of the panel or string and
from the negative terminals of the instrument to the negative terminal of the panel or string. This 4-wire connection
makes the voltage and current measurements of the panel or string independent and more accurate.
ATTENTION: use only the cables supplied for the electrical connections or, possibly, cables with suitable characteristics
and certifications.
If the measurement connection is made using cables other than those supplied, use cables that are as short as
possible.
Example of electrical connections without remote unit
Example of electrical connections with remote unit

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11.2. Remote Unit
The size of the plant may force you to place the instrument in a location far from the photovoltaic panels (for example,
an integrated plant on the roof with no possibility of making the electrical connections on the same level as the modules
or strings).
The UT925 remote unit (optional) can be installed next to the photovoltaic panels, thereby making it possible to transmit
the radiation, ambient temperature, and panel temperature measurements to the instrument in REAL TIME (using the
Bluetooth kit). This will make your testing very simple and accurate, and also let you view and store the measurements.
How to make measurements using the remote unit:
- Place the remote unit next to the panels.
- Use the included RS232 cable to connect the module or environment temperature probe and the parallel
pyranometer to the Bluetooth adapter.
- Switch the remote unit ON (green LED ON). The green power LED of the Bluetooth adapter will light (if not,
set the selector on its side to "PoRI").
The remote unit now is ready to transmit measurements to the I-V TRACER 935 instrument.
How to program the I-V TRACER 935 instrument for use with the remote unit:
- Turn the instrument On and open the "System" menu.
- Choose the Remote Unit - Bluetooth Adapter option.
- In the Bluetooth Address (MAC) option, enter the MAC number marked on the BLUETOOTH-RS232 adapter
connected to the remote unit.
- Click on "Apply" to confirm.
- Insert the USB-BLUETOOTH adapter into the USB port.
The instrument is now ready to receive measurements from the remote unit.
The LED on the USB-BLUETOOTH adapter will light only when measurements are activated from the "MODULE"
or "STRING" menu.
11.3. Module or String
The measurement functions are as follows:
Module: to measure a single panel, select the "Module" icon in the main menu,
String: to measure a string of panels, select the "String" icon in the main menu,
Main menu
Selecting the Module or String icon in the main menu displays the connection diagram on the screen; pressing "Continue"
displays the graph. This is how the choice of measurement of a single panel or of a string of panels is activated (the type
of measurement selected is displayed at the top centre of the screen). Independently of the selection made, the control
buttons under the graph let you control the measurements as described below:
• The maximum voltage between the inputs is 1000VDC. Do not measure voltage exceeding the limits in this manual.
• The maximum current the instrument tolerates is 10A DC. Do not carry out tests on FV module strings connected in
parallel.
• Never test FV modules or strings connected to the DC/AC converter.

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Start:
Pressing this button starts the measurement session; when the session is over, a graph showing the "I-V" curve in red
is created.
NOTE: Before the measurements are made, a test is run to verify the presence and correct operation of the environment
or panel temperature probe and the solar radiation (pyranometer) probe. If an error is found in the probe measurements
or the remote connection (if active), the measurement session is aborted. An error message appears on the screen;
check the connection and correct operation of the probe or the connection to the remote unit.
Single panel measurement window Error message box
Error message box Panel measurement graph
When "STRING" measurement is selected, a dialog box opens; the number of panels in the string to be tested must
be entered before the measurements are made.
String of panels measurement window Number of panels entry window

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At the end of the test the instrument provides the characteristic I-V measured under real OPC conditions (red colour)
concerning the single module or string tested, as shown in the screen below
Characteristic I-V curve under real OPC conditions
The comparison between the I-V curve measured under real OPC conditions and that characteristic of the producer
under STC conditions (green colour) can be requested.
Using the command COMPARISON the MODULES ARCHIVE menu is displayed: select the brand and module model
tested to be used in the comparison.
When clicking on Valid the parameters inserted in the modules archive (corresponding to those stated by the producer
of the modules) are used and the values measured by the instrument under real OPC conditions are recorded to the
STC reference standard conditions.
Comparison:
Pressing this button opens a window for entry of the brand and model of the panel measured, in order to compare the
measurements with the nameplate data; the measured values will appear alongside the nominal characteristics of the
panel. For a more accurate comparison, the age and corresponding presumed percentage of panel performance
degradation are requested; if you do not want to enter these data, press the "Do not apply" button.
Reference panel selection window Ageing values entry box
When the panel settings have been chosen, the results of the comparison are displayed in the bottom left corner of the
graph as follows:
Measurements @ STD – NO
For the case in which the verification of the manufacturer declared tolerance of maximum power % does not
fall within the range of values measured on the panel (or string).
Measurements @ STD – OK
For the case in which the verification of the manufacturer declared tolerance of maximum power % does not
fall within the range of values measured on the panel (or string).

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Measurement graphs with comparison results
Measurements:
Press the "Measurements" button on the command bar below the graph to access the menu for the following
functions:
Rs: use this command to activate the Series Resistance measurement function.
The RS series resistance is one of the main features of PV modules and significantly influences their I-V characteristics.
The series resistance is measured only on individual modules and, as stipulated in standard IEC/EN 60891, it is
measured in two stages, under different solar radiation conditions.
The first measurement must be made with a solar radiation value greater than 500W/m2. The second measurement
must be made with a solar radiation value that is at least 50 W/m2 lower. The conditions necessary to ensure that the
measurements are correct are checked automatically by the instrument. The measurements made will later be saved
along with the measurements of the I-V curve in the panel tab, following the procedure described in the Save (bold)
section.
To make this measurement, proceed as follows:
When the Rs function is selected, two commands are proposed:
Calculation: pressing this button starts phase 1 of the measurements; a window opens on the monitor, highlighting the
measured radiation value Irr (W/m²) and the "Phase 1 Measurement" button. Press this button to make the
measurements. If the solar radiation value is not correct, a warning message appears on the screen.
When the phase 1 measurements have been made, a window with a "Phase 2 Measurement" button appears.
If the solar radiation condition is correct, pressing this button starts the second measurement session; otherwise, a
warning message appears on the screen. In this case you must wait until the solar radiation conditions are within the
proper range as described previously. When these conditions are correct, the second measurement phase can begin.
NOTE: To make the Phase 2 measurement without waiting for the natural atmospheric variation of the solar radiation,
a screen, for example a sheet of polycarbonate like those used in shop windows, can be placed over the panel being
tested and the pyranometer measuring the radiation to filter the sun's rays and so create the right conditions for the
measurement.
NOTE: the IEC/EN 60891 standard indicates the procedures for transferring the values measured under real OPC
conditions to the reference standard STC conditions for a single module. Consequently, a negative result for a
measurement test on one string of modules could mean that every single module has to be measured in order to identify
the defective module or modules in the string.

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Below is a series of Rs measurement screens
Measured: clicking on the Measured button on the screen opens a window displaying the measurement made. The
window displays the Rs value and the two solar radiation test values.
Ambient measurements: Selecting this command displays the temperature and solar radiation measurements. The
Mod. Temp. and Amb. Temp. options are available for the reference. Indicates whether the measurements are being
made using the module temperature probe or the ambient temperature probe (previously selected).
The Remote Connection... message is present whenever the probes are connected via the remote unit.
Images of the Environment Measure Windows

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Electrical Data Measured window.
The window this command opens lets you choose between two options for the power curve to be displayed:
NOTE: the STC selection button is present only when the brand and model of the comparison panel have been entered.
Representations of the OPC and STC power curves
Save: press the Save button to access the Saving module measurement function. The window that opens for this
function lets you enter a comment, which is saved in the measurements tab. Press the Save button in the dialog box to
save the measurements and the comment.
The saved measurements can be displayed using the "Measurements Archive" Menu, accessed from the main menu
(page 9 of the "MEASUREMENTS ARCHIVE" chapter).
Dialog box for saving the measurements
Module (or String):
Module (or String): on selecting one of these commands the "Electrical Data Measured" table is displayed (OPC
conditions and STC reference standard if comparison previously requested).
Power:
This command displays on the I-V curve graph of the panel or string the power curve (yellow colour) as well.
OPC: the instrument shows the trend for power output from the module/string under real OPC conditions
(calculated with the measured values).
STC: the instrument shows the trend for power output from the module/string under STC standard conditions
(calculated by transferring the values measured under STC standard conditions in compliance with IEC/EN 60891
standard).