FRO­NIUS String Control 250/25 User manual

Operating Instructions
Data Communication
Fronius String Control 250/25
/ Battery Charging Systems / Welding Technology / Solar Electronics
EN-US
42,0426,0082,EA 005-12042012

ud_fr_st_et_01382 012012
EN-US
Dear Fronius Customer,
Thank you for choosing Fronius - and congratulations on your new, high-quality, high-
tech Fronius product. This introduction should provide you with general information
about the equipment. Please read it carefully to learn about the many great features of
your new Fronius product. This is the best way to get the most out of all the advantages
that it has to offer.
Please also note the safety information and the safety precautions for the product
installation location. Following all product instructions will ensure long-lasting quality and
reliability. And these are the essential ingredients for outstanding results.
Introduction

ud_fr_st_et_01382 012008

EN-US
IMPORTANT SAFETY
INSTRUCTIONS
SAVE THESE INSTRUCTIONS
General This manual contains important instructions for the Fronius String Control
250/25, that must be followed during installation and maintenance.
The Fronius String Control 250/25 is designed and tested according to
international safety requirements, but as with all electrical and electronic
equipment, certain precautions must be observed when installing and/or
operating the Fronius String Control 250/25.
To reduce the risk of personal injury and to ensure the safe installation
and operation of the Fronius String Control 250/25, you must carefully
read and follow all instructions and safety instructions in this manual.
Safety Instruc-
tions
The following section “Safety Instructions“ contains different warnings. A
warning describes a hazard to equipment or personnel. It calls attention to
a procedure or practice, which, if not correctly performed or adhered to,
could result in damage to or destruction of part or all of the Fronius string
Control 250/25 and/or other equipment connected to the Fronius String
Control 250/25 or personal injury.
All electrical installations must be made in accordance with the National
Electrical Code, ANSI/NFPA 70, and any other codes and regulations
applicable to the installation site.
For installations in Canada the installations must be done in accordance
with applicable Canadian standards.
Electrical
installations

2

ud_fr_se_sv_01381 012012
I
EN-US
Safety Instructions
This equipment has been manufactured using state-of-the-art technology
and in accordance with general safety regulations. However, incorrect
operation or misuse may endanger:
- the life and well-being of the operator or third parties
- the equipment and other property of the owner/operator
- the efficient operation of the equipment.
All persons involved with equipment startup, service and maintenance must:
- be suitably qualified
- be familiar with electrical installations
- have completely read and followed these operating instructions
The operating instructions must be available at the equipment location at all
times. In addition to the operating instructions, all applicable local rules and
regulations regarding accident prevention and environmental protection must
also be followed.
All safety instructions and warning signs on the equipment itself:
- must be maintained in legible condition
- must not be damaged
- must not be removed
- must not be covered or painted over
For information about where the safety instructions and warning signs are
located on the equipment, please refer to the “General“ section of your
equipment’s operating instructions.
Any equipment malfunctions which might impair safety must be remedied
immediately before the device is turned on.
Your safety is at stake.
General
NOTE! Indicates a situation which could adversely affect work results and may
cause damage to equipment.
„DANGER!“ Indicates an immediate danger. Death or serious injury may
result if appropriate precautions are not taken.
„WARNING!“ indicates a potentially dangerous situation. Death or serious
injury may result if appropriate precautions are not taken.
„CAUTION!“ Indicates a situation where damage or injury could occur. Minor
injury or damage to property may result if appropriate precautions are not
taken.
„Important“ Highlights tips for correct operation and other particularly useful
information. It does not indicate a potentially damaging or dangerous situation.
If you see any of the symbols depicted in the „Safety Rules,“ special care is required.
Explanation of
Safety Warnings!

ud_fr_se_sv_01381 012012 II
Maintenance and repair may only be carried out by an authorized specialist.
The use of third-party parts does not guarantee that they were designed and
manufactured according to operational demands and safety requirements.
Use only original spare parts (also applies to standard parts).
Do not carry out any alterations, installations or modifications to the device
without first obtaining the manufacturer’s permission.
Immediately replace any components that are not in perfect condition.
Safety Precauti-
ons at Equipment
Location
When installing devices with air vents, make sure that cool air can flow freely through the
vents unobstructed. The device should only be operated in accordance with the protec-
tion class listed on the rating plate.
The equipment may only be operated in compliance with its intended use.
Any other purpose does not constitute intended use. The manufacturer is not
responsible for any damages resulting from unintended use.
Intended use also includes:
- reading and complying with all general information as well as safety
information and warnings from the operating instructions
- compliance with all inspection and maintenance requirements
- installation as per operating instructions
Where appropriate, the following guidelines should also be applied:
- Utility company regulations regarding grid feed-in
- Information from solar module manufacturer
Intended Use
Operation and/or storage of the device outside of the stipulated range does
not constitute intended use. The manufacturer is not responsible for any
damages resulting from unintended use.
Please refer to the technical data in your operating instructions for informati-
on about permitted ambient conditions.
Ambient Conditi-
ons
Qualified Person-
nel
The servicing information contained in these operating instructions is intended
only for the use of qualified service engineers. An electric shock can be fatal.
Please do not perform any actions other than those described in the docu-
mentation. This also applies to qualified personnel.
All cables and wires must be secured, undamaged, insulated and adequately
dimensioned. Loose connections, scorched, damaged or under-dimensioned
cables and wires must be repaired immediately by an authorized specialist.

ud_fr_se_sv_01381 012012
III
EN-US
EMC Precautions In special cases, there may still be interference for the specified application
area despite maintaining standardized emission limit values (e.g. when
sensitive equipment is located at the setup location or when the setup
location is near radio or television receivers).
In this case, the operator is obliged to take proper action to rectify the
situation.
Grid connection Devices with a high output (> 16 A) can influence the voltage quality of the
grid due to a high current input into the main supply.
This can affect several device types in the form of:
- Connection limitations
- Requirements regarding permitted mains impedance *)
- Requirements regarding minimum required short circuit power *)
*) for each interface to the public grid
See technical data
In this case, the operator or the user of the device must make sure whether
or not the device may be connected, if necessary by contacting the power
supply company.
Information on
Noise Emission
Values
The inverter generates a maximum sound power level of <80dB(A) (ref.
1pW) at full-load operation according to IEC 62109-1.
The cooling of the device takes place via an electronic temperature control
system at the lowest possible noise level and depends on the power used,
ambient temperature and the soiling level of the device, etc.
A workplace-related emissions value cannot be provided for this device
because the actual noise level that occurs depends strongly on the installati-
on situation, the grid quality, the surrounding walls and the general properties
of the space.
EMC Device
Classifications
Devices in emission class A:
- Are only designed for use in industrial settings
- Can cause grid-bound and radiated interference in other areas
Devices in emission class B:
- Satisfy the emissions criteria for residential and industrial areas.
This is also true for residential areas in which the energy is
supplied from the public low-voltage grid.
EMC device classification as per the rating plate or technical data

ud_fr_se_sv_01381 012012 IV
Equipment with the CE marking fulfils the basic requirements of the Guideli-
ne Governing Low-Voltage and Electromagnetic Compatibility. (For more
information, please see the attachment and/or the “Technical Data“ section in
your documentation).
Safety Markings
The user is responsible for backing up data relating to changes made to
factory settings. The manufacturer will not accept liability if personal settings
are deleted.
Data Security
The manufacturer maintains the copyright to these operating instructions.
Text and illustrations are technically correct at the time of going to print. The
right to make modifications is reserved. The contents of the operating in-
structions shall not provide the basis for any claims whatsoever on the part
of the purchaser. We would be grateful for any comments or suggestions
regarding improvements and/or error corrections for the operating instruc-
tions.
Copyright
This device should not be disposed of in residential waste.
To comply with European Directive 2002/96/EC on Waste Electrical and
Electronic Equipment and its implementation as national law, electrical
equipment that has reached the end of its life must be collected separately
and returned to an approved recycling facility. Any device that you no longer
require must be returned to your dealer or you must find an approved collec-
tion and recycling facility in your area.
Ignoring this EU Directive may have adverse affects on the environment and
your health.
Disposal
Danger of damage to electronic components due to electrostatic discharge.
Take appropriate ESD precautions when replacing and installing compon-
ents.
ESD Precautions
Electrical Installa-
tions
Electrical installations may only be carried out in accordance with relevant
national and local standards and regulations.
The device should only be operated when all safety equipment is fully func-
tional. If safety equipment is not fully functional, there is a danger to:
- the life and well-being of the operator or third parties
- the equipment and other property of the owner/operator
- the efficient operation of the equipment
Safety equipment that is not fully functional must be repaired by an authori-
zed specialist before the device is turned on.
Never bypass or disable safety equipment.
Safety Precauti-
ons in Normal-
Operation

1
EN-US
Contents
General ............................................................................................................................... 3
Functional Principle ........................................................................................................ 3
Other System Requirements ........................................................................................... 3
Device Concept .............................................................................................................. 3
FCC Compliance ........................................................................................................... 4
Standards and Regulations ............................................................................................. 4
Intended Use .................................................................................................................. 4
Abbreviations and Descriptions Used ............................................................................. 4
Product listings and compliance ..................................................................................... 4
Components Supplied .................................................................................................... 4
Product Description ............................................................................................................ 5
Safety ............................................................................................................................. 5
Fronius String Control 250/25 - Housing .......................................................................... 5
Fronius String Control 250/25 - Connection Area ............................................................ 6
Selecting a Location ....................................................................................................... 8
Fronius String Control 250/25 Installation............................................................................. 8
Wall anchors and Screws ................................................................................................ 8
Recommended Screws for Mounting .............................................................................. 8
Installation Position ......................................................................................................... 8
Safety ............................................................................................................................. 8
Drilling Pattern ................................................................................................................9
Attaching the Fronius String Control 250/25 to a Concrete or Brick Wall .......................... 9
Attaching the Fronius String Control 250/25 to a Wooden Wall ...................................... 10
Attaching the Fronius String Control 250/25 to a Metal Carrier ..................................... 10
Knocking out Cable Input Openings and Mounting Conduits on the Fronius String Control
250/25 ............................................................................................................................... 11
General ......................................................................................................................... 11
Cable Input Areas .......................................................................................................... 11
Maximum Conduit Size ................................................................................................. 12
Recommendation for Inserting Cables .......................................................................... 12
Preparation .................................................................................................................. 12
Knocking out Cabel Input Openings on the Fonius String Control 250/25 ....................... 13
Mounting Conduits on the Fronius String Control 250/25 .............................................. 13
Connecting Solar Module Strings to the Fronius String Control 250/25 .............................. 14
General Information About Solar Modules ..................................................................... 14
Safety ........................................................................................................................... 14
Necessary Inside Cable Length of the Fronius String Control 250/25 ............................. 15
Notes for Connecting Solar Module Strings to the Fronius String Control 250/25 ........... 16
Terminal Assignment with Grounded Solar Modules ...................................................... 16
Connecting Solar Module Strings to the Fronius String Control 250/25 .......................... 17
Connecting the Fronius String Control 250/25 to the Inverter .............................................. 18
Safety ........................................................................................................................... 18
Cable Lugs for DC Cable ‘OUT’ ................................................................................... 19
Preparation .................................................................................................................. 19
Connecting DC Cable ‘OUT’ to the Fronius String Control 250/25 ................................. 20
Connecting the Fronius String Control 250/25 to the Inverter .......................................... 20

2
Criteria for the Proper Selection of String Fuses................................................................ 22
General ........................................................................................................................ 22
Criteria for the Proper Selection of String Fuses ........................................................... 22
Effects of Using Underrated Fuses ............................................................................... 22
Fuse Recommendations ............................................................................................... 22
Fuses ...........................................................................................................................23
Application Example ..................................................................................................... 23
Inserting String Fuses ........................................................................................................ 24
Selecting String Fuses .................................................................................................. 24
Inserting String Fuses ................................................................................................... 24
Safety ........................................................................................................................... 24
Connecting Data Communication Cables to the Fronius String Control 250/25 .................. 25
Connection Options ...................................................................................................... 25
Additional Insulation for Data Communication Cables ................................................... 25
Configuration example .................................................................................................. 26
Safety ........................................................................................................................... 26
Connecting RJ 45 Data Communication Cables to the Fronius String Control 250/25 ... 27
Connecting Unterminated Multi-core Data Communication Cables to the Fronius String
Control 250/25 .............................................................................................................. 27
Terminal assignments ................................................................................................... 28
Connecting an External Power Supply ............................................................................... 29
General ........................................................................................................................ 29
Safety ........................................................................................................................... 29
Connecting an External Power Supply........................................................................... 29
Setting the Address........................................................................................................... 30
Safety ........................................................................................................................... 30
General ........................................................................................................................ 30
Setting the Address - Examples .................................................................................... 30
Installing the Protection Against Contact and Closing the Fronius String Control 250/25 .... 31
Safety ........................................................................................................................... 31
Installing Protection Against Contact ............................................................................. 31
Closing the Fronius String Control 250/25 ..................................................................... 31
Settings ............................................................................................................................ 32
General ........................................................................................................................ 32
Initial Steps ...................................................................................................................32
Possible Settings for the Fronius String Control 250/25................................................. 32
Strings per Measuring Channel ..................................................................................... 33
Max. Energy Deviation .................................................................................................. 33
Threshold...................................................................................................................... 33
Display of Data and Status Messages............................................................................... 34
Data Display................................................................................................................. 34
Status Messages .......................................................................................................... 34
Replacing String Fuses ..................................................................................................... 35
Safety ........................................................................................................................... 35
Preparation .................................................................................................................. 35
Replacing String Fuses ................................................................................................. 35
Finally... ........................................................................................................................ 36
Technical Data ..................................................................................................................37
Input data ...................................................................................................................... 37
Output data (to the inverter) ........................................................................................... 37
General Data ................................................................................................................ 38

3
EN-US
Fronius String Control 250/25 (open)
General
Device Con-
cept
Functional
Principle
The Fronius String Control 250/25
is designed for use in grid-con-
nected photovoltaic systems with
several solar module strings.
Up to 25 solar module strings can
be integrated at the input of the
Fronius String Control 250/25 to
reduce these at the output to one
DC+ and DC- main line.
The Fronius String Control 250/25
monitors the incoming solar module
strings to detect errors in the solar
module field.
Status messages can be sent via e-mail or SMS when using the “Fronius
Solar.access“ software together with the “Fronius Datalogger.“
This allows a defective solar module to be detected quickly.
- Each set of 5 incoming solar module strings is grouped into one
measuring channel.
- 5 measuring channels record the total current of the respective con-
nected solar module strings over the entire charging day.
- In the evening, the Fronius String Control 250/25 calculates an ave-
rage value for all measuring channels.
- The Fronius String Control 250/25 compares the current of each
measuring channel with the average value of all measuring channels.
- If the Fronius String Control 250/25 detects that one of the measuring
channels deviates too much from the average, a status message is
sent to the Fronius Datalogger.
- The permitted deviation from the average is freely definable.
Other System
Requirements
- Fronius Datalogger
- PC with Fronius Solar.access software installed

4
Abbreviations
and Descripti-
ons Used
DC cable ‘OUT’ DC output cable from Fronius String Control 250/25
to inverter.
The polarity of the DC cable ‘OUT’ depends on how
the solar module strings are connected to the Fronius
String Control 250/25.
DC cable ‘IN’ Solar module strings from the solar modules to the
Fronius String Control 250/25.
Each solar module string has one DC+ cable and one
DC- cable.
The device is intended solely for use as a collector and measuring device
for the solar module DC strings.
The device may be operated only with the following inverters:
- Fronius CL 33.3 DELTA / 44.4 DELTA / 55.5 DELTA
- Fronius CL 36.0 WYE 277 / 48.0 WYE 277 / 60.0 WYE 277
Any other purpose does not constitute intended use.
The manufacturer shall not be liable for any damage resulting from such
improper use.
Intended use also includes following all information from the operating
instructions.
- 1 Fronius String Control 250/25
- 1 silicone tube
Intended Use
Components
Supplied
Your Fronius String Control 250/25 complies with the requirements for the
following standards "Inverters, converters and controllers for use in inde-
pendent power systems":
- UL1741-2005
- ANSI / IEEE C62.41
- C22.2 No. 107.1-01 (Sep. 2001)
The respective conformity declarations can be found in the appendix to
these operating instructions.
Standards and
Regulations
Product lis-
tings and
compliance
FCC Compli-
ance
This device complies with Part 15 of the FCC Rules. Operation
is subject to the following conditions:
(1) This device may not cause harmful interference, and
(2) this device must accept any interference received, including
interference that may cause undesired operation.

5
EN-US
WARNING! Operating the device incorrectly can cause serious
injury and damage. The following documentation should be
read and understood in its entirety before the described func-
tions are carried out:
- These operating instructions
- All system component operating instructions including
safety instructions
Fronius String
Control 250/25
- Housing
Item Description
(1) Cover screws (4 x)
(2) Cover
(3) Membrane
(4) Lower mounting clip
(5) Housing ground (inside the housing)
(6) Upper mounting clip
Sides for possible cable input openings
(2)
(3)
(1)
(4)
(6)
(5)
Product Description
Safety

6
(12)
(2)
(3)
(4)
(13)
(9)
Fronius String
Control 250/25
- Connection
Area
(7)
(5)
(6)
(8)
(10)
(11)
Item Description
(1) Address switches
(2) Measuring channel 5
(3) Measuring channel 4
(4) Measuring channel 3
(5) 25 Terminals with fuse holders for DC cable ‘IN’
cable cross section AWG 14 - AWG 8
(6) Measuring channel 2
(7) Measuring channel 1
(8) Connection 2 x M12 for DC cables ‘OUT’
(9) Connection 2 x M12 for DC cables ‘OUT’
(10) Connection 2 x M12 for grounding
(11) 2 x 8 Pressure type terminals for data communication cable
cable cross section max. AWG 14
(12) 25 Terminals for DC cable ‘IN’
cable cross section AWG 14 - AWG 8
(13) 13 Grounding terminals (e.g. for grounding of max. 25 solar
module frames)
cable cross section max. AWG 6
(1)
(14)
(15)

7
EN-US
Item Description
(14) 2 RJ 45 connections for data communication cable
(15) Connection for external 12 V DC power supply
Fronius String
Control 250/25
- Connection
Area
(continued)

8
Fronius String Control 250/25 Installation
Wall anchors
and Screws
Depending on the surface, different wall anchors and screws may be
required for installing the Fronius String Control 250/25. Therefore, these
wall anchors and screws are not included with the Fronius String Control
250/25. The installer is responsible for selecting the proper wall anchors
and screws.
In most cases, you should use 1/4 in. or 5/16 in. stainless steel or alumini-
um screws capable of supporting 46.26 lbs.
Recommen-
ded Screws
for Mounting
Installation
Position
The Fronius String Control 250/25 can be installed in any position from
horizontal to vertical. However, the cable inputs and outputs should point
downwards as much as possible.
Selecting a
Location
When selecting the location, please observe the following criteria:
- Install on a solid and planar surface; the housing must not be distorted
when screwing it down.
- The ambient temperature may not fall below -13 °F (-25 °C) nor exceed
+ 140 °F (+60 °C).
- NEMA 3R protection means that the Fronius String Control 250/25 is
not susceptible to water spray from any direction. However, the ma-
nufacturer recommends, if possible, that the String Control 250/25 not
be exposed to direct moisture or to a direct water jet (e.g., from sprink-
lers).
- Protect from direct sunlight and direct exposure to the elements.
- Install under the solar modules where possible.
CAUTION! Danger of injury by falling objects.
When working on elevated workplaces make sure that no
objects like housing cover, tools or other components of the
system can fall down. If necessary, install a wire mesh, a safe-
ty net or suitable protection devices.
Safety

9
EN-US
3
2
3
5
4
4 x
1
Attaching the
Fronius String
Control 250/25
to a Concrete
or Brick Wall
1
2
1
1
3
5
4
2
2
3
5
4
Drilling Pat-
tern
(a)
(b) (c)
(d)
(a) (a) = 8.86 in (225 mm)
(b) = 28.86 in. (733 mm)
(c) = 29.4 in. (746 mm)
(d) = 9.84 in. (250 mm)

10
Attaching the
Fronius String
Control 250/25
to a Metal
Carrier
1
4
1
4 x
2
3
Attaching the
Fronius String
Control 250/25
to a Wooden
Wall
1
1
1
3
2
2
2
1