weidmueller 4000001903 PV DC Combiner Box Instruction Manual

weidmueller 4000001903 PV DC Combin

Product Information

PV DC Combiner Box

The PV DC Combiner Box is a device used in photovoltaic systems to combine the DC outputs of multiple solar panels into a single output. It is designed to ensure safe and efficient operation of the photovoltaic system by providing surge protection, fuse holders, terminals, and other necessary components.

Device Description

The PV DC Combiner Box includes the following components:

• Enclosure: The housing that protects the internal components.
• DC Switch: A switch used to control the DC power flow.
• Surge Protection Device (SPD): Provides protection against voltage surges.
• Fuse Holders: Holds fuses for overcurrent protection.
• Fuses: Protects against excessive current flow.
• Terminals: Connectors for the input and output cables.
• Conductors: Wiring components for electrical connections.
• Input Terminals: Connects the DC outputs of solar panels.
• String Monitoring Device (Optional): Monitors the performance of the solar panel strings.

Transport and Storage

When transporting or storing the PV DC Combiner Box, follow these guidelines:

• Transport the device with care to avoid damage.
• Unpack the delivery carefully.
• Store the combiner box in a dry and secure location.
• Establish connections according to the provided instructions.

Installation

To install the PV DC Combiner Box, follow these steps:

1. Choose a suitable installation site.
2. Position the combiner box securely.
3. Fix the box in place.
4. Install the combiner box according to the provided instructions.
5. Insert the fuses into the fuse holders.
6. Connect the inputs from the solar panels.
7. Connect the outputs to the desired destination.
8. Connect the grounding cable.

Connection of Communications (Optional)

If communication features are available, follow these steps:

1. Wire the communications according to the instructions.
2. Connect the RS485 to the Solar SMS.
3. Configure the Modbus address and RS485 serial settings.
4. Follow recommendations when using serial converters.
5. Follow recommendations when configuring the SCADA system.

Commissioning

To commission the PV DC Combiner Box, follow these steps:

1. Check the main indications and perform necessary checks.
2. Start up the combiner box according to the instructions.

Accessories and Replacing Parts

If accessories or parts need to be replaced, refer to the following:

• Replacing fuses
• Replacing a switch disconnector
• Replacing string monitoring devices
• Replacing surge protection arresters

Cleaning
To clean the PV DC Combiner Box, follow the provided instructions.

Maintenance and Service
For maintenance and service requirements, refer to the provided instructions.

Safety

The PV DC Combiner Box should be handled with caution to prevent harm to individuals and damage to materials. It is important to observe the safety instructions and warning notices provided in the documentation to ensure safe operation of the device.

Failure to follow the safety and warning notices may result in damage to people and materials.

About this documentation

Target group and contents
This user manual is addressed to personnel that is involved in mechanical and electrical installation of a Weidmüller PV DC COMBINER BOX and to service and maintenance personnel.
This user manual gives a general overview about the complete range of PV DC COMBINER BOX, the individual components, their function as well as their correct handling.
An individual datasheet providing the specific information is attached to each combiner box. This information specifies the original features of each combiner box.

Symbols and notes
The warnings in this documentation are structured differently depending on the severity of danger.

| DANGER
---|---
Imminent risk of life!

Notices with the signal word “DANGER” warn you of situations which will result in serious injury or death if you do not follow the instruc- tions given in this manual.

| WARNING
Possible risk of fatality!

Notices with the signal word “WARNING” warn you of situations which may result in serious injury or death if you do not follow the instructions given in this manual.

| CAUTION
Risk of injury!

Notices with the signal word “CAUTION” warn you of situations which may result in in- jury if you do not follow the instructions given in this manual.

ATTENTION
Material damage!

Notes with the signal word “ATTENTION” warn you about hazards which may result in material damage.

The situation-dependant safety notices may contain the following warning symbols:

Additional formatting is used in the rest of the text which has the following meaning:
Text items next to this arrow constitute informa- tion which is not related to safety, but which provides important information regarding correct and effective work.

• You can recognize handling instructions from the black triangle in front of the text.
  • Lists are indicated with dashes.

Before start working with the product, read the documentation completely!
Keep the manual as well as the attached data sheet stored so that it can be inspected by operating personnel at any time.
The document is available to download from the Weidmüller website.

Safety

This section includes general safety instructions for handling the PV DC COMBINER BOX. Specific warning notices for specific tasks and situations are given at the appropriate places in the documentation. Failure to observe the safety and warning notices can result in damage to people and material.

General safety notice
Proper transport, storage, installation, commissioning, op- eration and maintenance are required to ensure that the products operate safely and without any problems.
The permissible ambient conditions must be observed.
Ensure protection against unauthorized opening. Unauthorised people must neither open nor operate the combiner box.
Photovoltaic systems can generate hazardous voltages. Two different ways of service activities are allowed on these products:

• “Working under voltage”: Only electricians who have a qualification for working under voltage are allowed to carry out service activities under voltage. Observe the local regulations and make use of appropriate personal protective equipment.
• “Working without voltage”: Electricians and trained persons are allowed to carry out work without voltage, when input and output connections are safely disconnected and secured against re-connection. Observe the local regulations and make use of appropriate personal protective equipment.

Before connecting the cables to the input connectors, make sure that the fuses are not inserted and that the open circuit voltage of the corresponding string is equal to the other strings.
Do not extract or insert fuses under load. Before manipulating a fuse make sure there is no reverse current flowing into the corresponding string.
If the installation regulations are violated, all warranty and liability claims will be voided.
If a malfunction on a combiner box cannot be fixed after following the recommended measures, the product in question must be sent back to Weidmüller. Weidmüller does not assume any liability if the product has been tampered with.

Intended use
The PV DC COMBINER BOX series are intended for use in photovoltaic (PV) systems. The product joins different strings of a PV system and contains DC over-current and over-voltage protections for string level. String monitoring devices are provided optionally.

Weidmüller products may only be used for the applications described in the catalogue and in the relevant technical documentation. If products and components from other manufacturers are used, these must be recommended or approved by Weidmüller.
The observance of the documentation is part of the intended use.

Personnel
All activities described in this document may only be carried out by specialists and instructed persons with the following qualifications:

• Knowledge of the functionality and principle of PV systems
• Training in handling dangers and risks during installation and handling electrical devices- es and systems
• Knowledge of applicable standards and guidelines
• Knowledge and observance of these operating instructions and the safety instructions contained therein
  It is a common practice in the sector to apply the five safety rules described in the standard EN 50110. Anyway, qualified electricians must analyze case by case on each installation the best way to proceed with safety.

The five safety rules are the following:

1. Disconnect completely
2. Secure against re-connection
3. Verify that the installation is dead
4. Carry our earthing and measures against short-circuiting
5. Provide protection against adjacent live parts

Legal notice
The PV DC COMBINER BOX is CE-compliant in accord- ance with Directive 2014/35/EU (Low Voltage Directive) and with Directive 2014/30/EU (EMC Directive).

Device description

Product overview

PV DC COMBINER BOX is a complete range of tai-
lor-made Level 1 combiner boxes for utility-scale photovoltaic systems. The combiner boxes are installed to join and protect the DC strings that go from the PV panels to the solar inverter.
The PV DC COMBINER BOX product range offers solutions from 8 to 32 inputs and 1 or 2 outputs. These can be designed for systems with string voltage of 1000 or 1500 V DC.
The necessary string cables (+ and -) are to be connected at the inputs whereas one or two DC+ and DC- main cables will be at the output side. The output cables must be connected to a Level 2 combiner box, which will join DC+ and DC- from other Level 1 combiner boxes, or directly to the solar inverter.

Parameters influencing the selection of the optimal PV DC COMBINER BOX

• Ambient temperature
• Degree of protection needed
• DC voltage range
• ISC of the PV string
• DC earthing system
• Number of inputs
• Number of outputs
• Fuses in one or both poles (by default in both poles)
• Type of surge protection (by default Type II SPD)
• Type of input terminals (by default multivia cable glands)
• String monitoring (if yes: single or pair monitoring)

Figure 3.2 Main components of the PV DC COMBINER BOX (exam- ple)

1. DC Switch
2. String monitoring device Solar SMS (optional)
3. Output DC+/-
4. Ground terminal
5. Fuse holders
6. Input DC +/- (cable glands, alternatively WM4 C connectors)

Enclosure
The enclosure of the PV DC COMBINER BOX is made of Glass Fibre Reinforced Polyester (GFRP). The en- closure provides IP65 and IK07 or higher in accordance with IEC 62208. Each enclosure is equipped with hinged door(s).

DC Switch

The PV DC COMBINER BOX has a DC disconnection switch by default. The DC voltage of the switch depends on the voltage of the PV string. The switch disconnector mak- ing and breaking capacity (according to the IEC 60947-3) has been selected to assure that it can switch the circuit at full load at the maximum operating temperature.

Surge protection device (SPD)

The surge protection device has been selected corre- sponding to the customer requirements and in accord- ance with the standard for low-voltage surge protective devices IEC 61643-32.
Special units for 1 kV or 1.5 kV are used to provide the best performance in each specific system configuration.

Fuse holders

The fuse holders provide the interconnection between the string input cables and other elements inside the combiner box. The fuse holders ensure that the fuses are placed in the optimum position to perform their protection function. Additionally, the type of fuse holders (IP 2X) enables the au- thorised personnel to operate the fuses in a safe manner. These products allow multiple setups which helps to build up specific tailor-made solutions of PV combiner boxes.

Fuses

The fuses protect the PV strings against over-current situ- ations. The PV DC COMBINER BOX is provided with gPV fuses in accordance with IEC 60269-6:2010.
Each design of combiner box contains the most suitable fuse rating specially selected for each project, depending on Isc of PV strings, on voltage rating and on ambient tem- peratures.
To assure the best performance of the complete solution, PV DC COMBINER BOX is delivered with fuses, optional without.

ATTENTION
Material damage!
Only use fuses with silver plated end-caps. If you have to replace a fuse inside a PV DC COMBINER BOX, use the same type of fuses delivered with the original combiner box. Pay special attention to the voltage and current rate as well as the size and material.

Terminals

The fuse holder terminals allow to connect the string ca- bles safely.

Conductors
To perform the connections, regard the following conductor specifications:

mm2
Wire end ferrule, DIN 46228-1, min. / max.| 0.5 mm2 … 16 mm2
Plug gauge acc. to EN 60999 a x b; Ø| 5.3 mm (B6)
Conductor cross section| Tolerance of stripping length
---|---
< 4 mm2| ± 1 mm
6 – 10 mm2| ± 1.5 mm

16 mm2| ± 2 mm

In order to assure a reliable connection, it is re- commend to use appropriate crimping tools, as an example PZ 10 HEX (Order No.1445070000). Please check the Weidmüller product catalogue to select the appropriate tool.

Input terminals

The PV DC COMBINER BOX is equipped either with cable glands or with special photovoltaic connectors WMC 4.
The WMC 4 connectors reduce the installation time as well as the maintenance time. They fulfill the DIN EN 50521 and are TÜV certified.
The cost-efficient cable glands on the other hand allow the installer to adjust the necessary number of cables even in the field.

String monitoring device (optional)

In case the PV DC COMBINER BOX is equipped with a string monitoring device, this device is a Solar SMS with PUSH-IN terminals.
This device simplifies the connection work inside the combiner box and reduces maintenance tasks due to the PUSH IN terminals. The Solar SMS can operate at full load (25 Amps) at maximum temperature range (+70 ºC).

General technical data

Main application features

Inputs| 8 to 32
Outputs| 1 or 2
Operating ambient temperature range| -20 ºC … +50 ºC
Rated DC voltage| ≤ 1.000 V DC or ≤1.500 V DC
Input connectors| WM4 C connectors or cable glands
Input connector technology| Screw tied inputs (up to 16 mm2 cable)
DC earthing system| Floating, negative grounded or positive grounded system
Main electrical current protections
Rated DC current per input| ≤ 48 A (single, double, or triple string connection)
Maximum fuse rating| 30 A for 10×38 / 32 A for 10×85 / 75 A for 22×58
Protection against overcurrent| gPV fuse-links according to IEC 60269-6
Fuses| 10×38 mm for 1 kV, 10x85mm and 22×58 mm for 1.5 kV
Switch-disconnector| Yes (optional)
Switch-disconnector making and breaking capacity (acc. to IEC 60947-3)| ≤ 500 A (other options on demand)
Enclosure
Enclosure material| GFRP (Glass Fiber Reinforced Polyester)
Enclosure fixing system| Wall mounted or pedestal
Degree of protection (acc. to IEC 60529)| IP65
Form factor| Cabinet with hinged door or removable cover
Surge protection
Surge protection device| Type I, Type II and Type I+II
Auxiliary contacts| optional
Surge protection on EIA-RS485 ports| optional
String monitoring (optional)
String monitoring device| Solar String Monitoring System
Main monitored parameters| Voltage, current, temperature, DI status and auxiliary alarms
Communication| RS485 (3-wires) and LoraWAN
Protocol| Modbus/RTU
Self-powered| Yes (DC/DC power supply)
Standards
Standards| IEC 61439-2 ed 3.0 / EN 61439-2:2011

Please regard the data sheet attached to each combiner box.

Transport and storage

Transporting

• Always wear safety shoes with foot protection when transporting and unpacking the combiner box.
• Mind the total weight and use appropriate transportation equipment.

Unpacking the delivery

• Before unpacking, check that the product contained is the one ordered (see the label laterally on the package)
  If the product that received is not what you have requested or is incomplete, please do not open the shipping boxes. Please contact your Weidmüller representative office, your distributor or the relevant contact person immediately.

• Check the delivery for completeness. For the scope of delivery, see the enclosed data sheet and dispatch documents.
  If you detect any issue or damage, do not install the unit. Please contact your Weidmüller representative office, your distributor, or the relevant contact person immediately.

• Store away the transport packaging.

• Ensure that the operating instructions are always accessible to the user.

Storage
Make sure that in case of long-term storage the following conditions are met:

• Ambient temperature: -25 °C to +40 °C
• Relative humidity: 0 % to 50 %

ATTENTION
Material damage!
The combiner box must be stored lying flat on the rear side. Otherwise, the cable glands and connectors at the bottom of the enclosure may be damaged.
In the event that, after the storage there is any ingress of dirt, pollutants or liquid into the equipment, or the formation of condensation, damage or any other failures the equipment must not be commissioned until the correct remedial procedure has been discussed with and approved by Weidmüller.

Establishing connections

ATTENTION

Material damage!
The tension of the cables may cause mechanical stress to the enclosure. For this reason, depending on the installation height, a strain relief underneath the combiner box may be needed. Regarding the national regulations.

• Use only electrical solar cables rated for the voltages, currents and environmental conditions (temperature, UV, etc.) expected at the installation site.
• Ensure that you lay all cables with short-circuit protection and ground fault protection.
• As feeders use only single-core cables with double or reinforced insulation in accordance with IEC 60364-5- 52.
• To ensure short-circuit-proof and ground-fault-proof installation in accordance with IEC 60364-5-52, the following requirements must be fulfilled:
• Cables must not be installed in the proximity of combustible materials.
• Cables must be accessible.
• Cables must be protected against mechanical damage.
• Do not lay the wires over sharp edges.

Installation

Installation site
The PV DC COMBINER BOX is suitable for protected outdoor installation. Regard the following aspects when selecting the installation site:

• The location must be protected from the weather and direct sunlight.
• The location must be easily accessible for installation work and later maintenance work.
• The installation site must not be in close proximity to easily flammable materials, gases or vapors.
• The combiner box must be positioned as described in the following section.
• It must be ensured that unauthorized personnel cannot access the combiner box.
• The installation area must be stable enough to enable installation and maintenance work safely.
• The combiner box and especially the feeder conductors must be installed in such a way that damage cannot be caused by rodents.
• Regard the permissible ambient conditions:
• The temperature range is indicated on the label inside the box.
• The relative humidity may temporarily be as high as 100 % at a maximum temperature of +25 °C.
• Ensure that no object is blocking the pressure compensation elements.
• Ensure that neither the string input cables, nor the PV output cables will be damaged by a lawnmower or similar agricultural implement.
• When installing, ensure rain cannot penetrate the combiner box.

Exposure to direct sunlight and direct rain for extended periods and excessively high or low temperatures can result in a shorter lifetime or damage to the internal components of the com-
biner box.
To protect the combiner box against direct sunlight and rain, it shall be installed under the photovoltaic modules or a protective canopy or sunshade. Take air circulation around the box into account.

Positioning of the combiner box
The PV DC COMBINER BOX is designed to be installed vertically with the cable glands or connectors leading down. Merely a positive inclination from 15º to 90º is allowed.

The combiner box must not be installed horizontally lying flat on the rear neither in any other orientation.
The combiner box must not be installed indoors.

Fixation
The fixation of the combiner box directly affects the proper performance and the lifetime of the product.
Ensure that the requirements described in chapters 5.1 and 5.2 will also be observed.

Mounting material
Most of the Weidmüller combiner boxes are supplied with metal or plastic mounting lugs, depending on the model. Fixation screws are not delivered as standard with each model. Please check your delivery before starting the installation.

Requirements
The PV DC COMBINER BOX shall be fixed to a suitable and stable metallic structure or a wall that will support the weight of the combiner box during the entire lifetime.
Always use all fixations that are supplied with the product. In case the installation is done on a pedestal, this should be fixed on the top of it with the specific accessories supplied with the unit.

Installing the combiner box

CAUTION
Risk of injury due to the size and the weight!

• Always install the combiner box with two persons to avoid any injury or accident.
  Installers should be qualified for the specific works according IEC standards and/or local regulations and should bring the necessary safety equipment.

ATTENTION
The product can be destroyed!

• Never drill the enclosure to add any extra hole or to modify any of the existing holes. Otherwise the IP protection will get lost as well as the product warranty.
• If necessary lay down the combiner box only on the rear side after unpacking. Otherwise, the cable glands and connectors at the bottom of the enclosure can be damaged.
  • Remove the combiner box from the original packaging.
  • Measure the exact distances between the drilling holes and mark the positions in the mechanical structure (or wall).
  • Drill the holes in the mechanical structure (or wall).
  • Mount the combiner box using the fixing lugs.
  • Check the installation:
  • Verify that the combiner box is correctly secured and fixed.
  • The surface of the enclosure should be totally flat. If the combiner box is bended over the edges, the tightness is not guaranteed.

Each model has been designed according individual specifications and it has been approved by customer.

Enclosures mounting lugs and fixing points1)

Inserting the fuses
For each string voltage (1000 V DC and 1500 V DC) there are two types of fuse holders that can be used in the PV DC COMBINER BOX:

• for 1000 V
• for 1500 V

WARNING
Do not operate under load.
A serious damage on persons and equipment can occur by high voltage.

• Ensure that there is no current flowing through the strings.
• Open the fuses carrier by pulling the fuse holder handle.
• Insert the fuse link laterally into the fuse holder carrier and push gently.
• Proceed in this way with all fuses that are to be inserted.

Connection of the inputs
The enclosure is equipped either with cable glands or with
PV connectors (WM4 C or PV stick).
In order to conduct proper connections it is recommended to use wire end ferrules as well as appropriate stripping and crimping tools.
Input connections via cable glands
Each multivia cable gland has entries for 8 different cables. Pay attention to the string number as well as the polarity in order to avoid mistakes during connection.
Make sure that you have the electrical drawing provided with the combiner box to hand.

• Insert the DC string input cables through the multivia cable glands into the interior of the enclosure.
• Strip the conductor for 18 mm with an appropriate tool.
• Crimp the conductor with a tubular wire end ferrule with 18 mm length of the sleeve (the conductive part).
• Check the terminal in the electrical drawing and insert the conductor in the fuse holder connection insert.
• Use an appropriate screwdriver and thighten the screw with the torque indicated in the product drawing.
• Pull down the cables to assure that all of them are well connected.
• Make sure there is sufficient strain relief for the DC main lines and DC string input cables.
• Make sure that the cables are not mounted under mechanical load which could create an undesirable force.
• Proceed in this way with all input cables needed.

Input connections via PV connectors
Both connectors (box connector and field connector) must be from the same brand and same model to ensure the correct performance and reliability of the solution. Please assure that there is 100% compatibility between both connectors. Weidmüller supplies the range of combiner box- es with WM4 C terminals, so it is mandatory the usage of same connector.
If another connector should be used, it needs a specific authorization by Weidmüller.
With PV connectors there is no need to get access inside the PV combiner box because all the cabling is already done. The installer has only to connect the DC string cables to the PV connectors at the bottom side of the enclosure by using a WM4 C connector or PV-Stick.
To read more about these connectors, please check operating instructions on the Weidmüller website.

• Follow the instructions in the user manual coming with the PV connectors.
• Pull down the cables to assure that all of them are well connected.

Connection of the outputs
The output connections depend on the design of each tailor-made PV DC COMBINER BOX. The output cables must be connected to the poles of the switch disconnector or to the terminals prepared for this purpose. Regard the delivered datasheet for the cable glands and a description of the clamping area.
Please ensure that the cable that you are going to use fits with the specifications.

The cross section of the conductor must be selected according to the rated current of the system and to the size of the cable gland of the combiner box.

• Use copper or aluminum cables only. When using aluminum cables regard the section “Preparing aluminum conductors” before starting the installation.
• Weidmüller is not responsible for the performance of the terminal lugs, terminal ring or terminal cage neither the output cable selected.

WARNING
Do not operate under load.
A serious damage on persons and equipment can occur by high voltage.

• If string cables form the field are connect- ed into the terminals, ensure that the power supply is disconnected.
• Ensure that the DC switch disconnector is in OFF position.
• Ensure that there is no voltage in the out- put cables and that all safety measures have been considered.
• Before starting the installation check that the terminal lugs will fit through the cable glands.
• Insert the DC main cables through the cable glands into the enclosure.
• Regard the polarity when connecting the DC conductor to the appropriate terminal lug, ring terminal or cage terminals and follow the instructions of that component to crimp it in the right way.
• Connect the DC conductors to the stud terminals or di- rect to the switch-disconnector.
• Check the terminal in the electrical drawing provided with the combiner box.
• Check and apply the right tightening torques to the terminal lugs of the switch disconnector (the correct tightening torques can be found in the specific documentation inside each PV DC COMBINER BOX).
• Tighten the cable glands.
• Make sure there is sufficient strain relief for the DC main lines/DC feeder cables.
• Close all unused cable glands with blanking plugs to prevent moisture from penetrating the combiner box.

Preparing aluminum conductors

• Aluminum conductors are only suitable for installation sites that are free from humidity or aggressive atmospheres.

• It is recommended to use bimetallic connectors.

• Use neutral grease (acid free and alkali-free vaseline) to protect the surface of the aluminum from oxidation.
  As a well-known characteristic aluminum forms a thin,non-conductive layer of oxide as soon as it is exposed to the air. This layer increases the contact resistance between the aluminum conductor and the current bar of the terminal which can lead to poor contact. As a precondition regard the following steps to prepare the aluminum conductors:

• Scrape the stripped end of the conductor carefully, e.g. with a knife, to remove the layer of oxide.
  Do not use brushes, files or emery paper be- cause particles of aluminum can be deposited on other conductors.

• Coat the end of the conductor immediately with neutral grease, and connect it to the terminal immediately.

• Tighten the screws with the maximum permissible tightening torque.
  Repeat the above procedure each time after the conductor has been disconnected and shall be reconnected.

Connection of the grounding cable
The PV DC COMBINER BOX is designed without any metallic mounting plate or similar. The enclosure is made of GFRP (Glass Fiber Reinforced Polyester). Therefore the unique ground connector is used for the surge protection. Note that this cable must be connected to provide the cor- rect operation of the surge protection device (SPD).
Protective conductors and other earthing conductors for functional and protective purposes cannot generally be considered as equipotential bonding dedicated for surge and lightning protection.

According to the standard CLC-TS 50539-12, the cross-section of connecting conductors to SPDs on the DC side of PV installations must be as it follows:

• Earthing conductors of SPDs Type I shall have a minimum cross-section of 16 mm2 copper or equivalent or equal to the cross-section of live connectors, if greater than 16 mm2.

• Earthing conductors of SPDs Type II shall have a minimum cross-section of 6 mm2 copper or equivalent or equal to the cross section of live connectors, if greater than 6 mm2.

• The cross section of the connecting conductors from the SPD to live conductors shall not be smaller than the cross-section of the live conductors of the associated circuit.
  To ensure that the live conductors of the PV installation can withstand the surge current stress, the cumulated cross-section of these conductors should not be less than 6 mm2 for SPD Type II and 16 mm2 for SPD Type I.
  Otherwise, if in the combiner box there is a specific ground- ing terminal for this purpose, check the specifications on the electrical diagram attached inside the product.

• Strip the conductor for 12.5 mm using an appropriate tool.

• Verify with the electrical diagram attached in the combiner box where to connect the cable (ground connector of the SPD or a specific terminal for this purpose).

• In case the grounding cable is connected to a specific terminal, connect the cable and tighten it with the screw (2 …. 4.5 Nm).

• Verify the correct connection of the grounding cable to the terminal.

Connection of the communications (optional)

This section is needed if the combiner box contains a string monitoring device Solar String Monitoring System (from now on Solar SMS). This device has a communication port RS485. The figure below shows how to connect multiple combiner boxes in a master-slave configuration using RS485 connection and its corresponding termination.

• The Solar SMS is a slave and a server from the viewpoint of the Modbus standard.
• A SCADA or the program running in a PLC/datalogger is a client from the viewpoint of the Modbus standard.
• A RS485-to-Ethernet converter or the hardware of a PLC/datalogger is a master from the viewpoint of the RS485 standard.

ATTENTION
Material damage!
RS485 wiring requires technical skills and tools different to those available to regular electricians. Please ensure that this step of the equipment installation is performed by staff with the right skills and tools.

This equipment complies with the latest RS485 and Modbus standards, which are the official sources of information. The installation staff must refer to the following documents, which always have priority:

• TIA/EIA–485–A: Electrical characteristics of generators and receivers for use in balanced multipoint systems
• TIA TSB–89–A: Application guidelines for TIA/EIA– 485–A
• Modbus application protocol specification v1.1b
• Modbus over serial line specification and implementation guide v1.02

The RS485 port of this equipment is floating with regards to the rest of the circuit. This is accomplished by means of dedicated DC/DC converters and optocouplers which provide a double insulation barrier between the communications ports and the PV-side terminals. From the user perspective, this means reliable communications, no ground loops and full safety even under severe surges.

Wiring the communications

DANGER
Imminent risk of life!
High voltages up to 1.000 or 1.500 V DC are present in the live parts. Touching live parts can result in death or serious injury due to electric shock.

• Before starting any work in the PV DC COMBINER BOX:
  • disconnect the DC switch
  • ensure that there are no fuses inserted into the fuse clips of the PCB boards

ATTENTION

Material damage!
A wrong installation can create a lack of communications,but also, it can damage the equipment.

• Please pay attention when wiring RS485 cables.

All the units shipped out from Weidmüller have their RS485 ports thoroughly tested right at the end of the production line. Weidmüller will not cover under warranty Solar SMS units that have their RS485 transceiver IC damaged due to wrong wiring or due to surges.
Cable requirements
The RS485 cable used to wire this equipment must fulfill the following specifications:

• Shielded twisted pair with 1.5 or 2 pairs (preferably 1.5 pairs)
• Braid shield, not foil shield
• 120 Ω characteristic impedance
• Cross section of individual wires 0.2 mm2 (AWG24) or larger

The following are two examples of proper RS485 cable:

• Belden: 3106 A
• Lapp Cable Unitronic Bus LD 2×2×0.22 (part number 2170204)

Connecting the RS485 to the Solar SMS
By default, the PV DC COMBINER BOX with monitoring comes with the internal communications pre-wired. This means that there is a communication cable between the device and 3 terminals at the bottom side of the enclosure. Depending on each design, these terminals are not present, so user must connect the communication cable directly on the RS485 communication terminal of the Solar SMS. In any case, there will be 3 terminals available to connect.
The table below shows correspondence between alternate names for RS485 pins. The reason for choosing D+/D– over B/A or D1/D0 in this equipment is to avoid confusion with certain third party products on the market with erro- neously swapped B/A and D1/D0 pins. The names D+/D– cannot lead to confusion.

Function| Non-invert- ing pin| Inverting pin| Reference pin
---|---|---|---
RS485 standard| B| A| C
Modbus standard| D1| D0| Common
Weidmüller| D+| D-| C

Even if the field communication wires are connected to 3 terminal blocks it is important to pay attention to the information about appropriate cable section and length.

Please regard the following aspects when wiring the RS485:

• The RS485 bus topology must be a daisy chain (see picture below).
• Short stubs inside the combiner box should be at maximum 2 meters long.
• We recommend a bus length of 500 meters at maximum, even though the RS485 standard allows up to 1200 meters at low bit rates (i.e. 9600 bps and 19200 bps).
• Each end of the bus requires a 120 Ω 10 % ½ W termination resistor between D+ and D– (see the RS485 wiring diagram). One end of the bus will be the RS485 master which may or may not include an internal termination option. The other end will be inside the combiner box farthest away from the master in terms of RS485 cable distance.
• This equipment loads the RS485 bus with 1/8 UL (Unit Load).
• It is recommended not to mix Solar SMS and other RS485 slaves within the same bus.
• The D+ and D– of each Solar SMS should use one twisted pair of the cable, leaving the remaining wire (in cables with 1.5 pairs) or the remaining twisted pair (in cables with 2 pairs) for the C connection.
• Always make sure that D+, D– and C use the right color-coded wire of the cable. It is a must to connect the C pin of all the Solar SMS and the RS– 485 master together (see picture below).

Damages to the RS485 transceiver IC of this equipment due to the following wiring errors will not be covered under warranty:

• Connecting the C pin of this equipment to protective earth anywhere except in one point (at the master end). This connection may be already done internally inside the RS485 master.
• Connecting the C pin of this equipment to the cable shield inside a combiner box.
• Using non-twisted pair or non-shielded cables.
• Connect RS485 cables in a different way than the specified in the wiring diagram of this user manual.

| WARNING
---|---
Risk of electrical shock and product damage.

Too short RS485 cables can cause mechani- cal strain to the equipment.

►  Ensure that the RS485 cables are long enough.

Regard the following instruction notes.

• Always wire the C pin first and only afterwards wire the D+ and D– pins.
• It is very important NOT to connect the shield to the C pin in any combiner box (see the RS485 wiring dia- gram).
• The daisy chained shield must run non-stop from end to end of the RS485 bus.
• Leave the shield floating (i.e. unconnected) at the far end of the RS485 bus (i.e. the combiner box farthest from the RS485 master in terms of cable length).
• Tie the shield directly to protective earth at the RS485 master end.
• Ensure that the C pin is not connected to protective earth anywhere else in the whole RS485 bus (keep in mind that some RS485 masters may already tie internal- ly the C pin to protective earth or to their power supply ground!). This connection makes sure that the RS485 common-mode voltage stays close to earth potential instead of rising to dangerous voltages due to stray capacitances and conductances in the network.
• Tie the C pin to protective earth at the RS485 master end (see RS485 wiring diagram).

The RS485 shields should be joined as shown below.

• Make sure that the metal braid of the EMC tie has safe contact to the braided shield of the cables.
• Keep the stripped length as short as possible.
• Make sure that the wire-end ferrules are correctly tighten and crimped.

Configuration of the Modbus address and the RS485 serial settings
The Modbus device address and the RS485 serial settings are configured by setting the DIP switch SW1.

Use the DIP switch (SW1) to configure the Modbus device address and the RS-485 serial settings. The first eight positions of the DIP switch (SW1) marked as “ID ADDRESS” are used to configure the ID of the Solar SMS device. The last two positions of the DIP switch (SW1) marked as “BR” and “P” are used to configure the RS-485 serial settings.

Description of SW1 (Modbus device address)
The following table specifies the binary coding of the Modbus device address via DIP switch. The factory default slave address is 1 (i.e SW1.1 in the ‘ON’ position and SW1.2 to SW1.8 in the ‘OFF’ position). As an example, the DIP switch coding for Modbus address 175 is shown (10101111 in binary).

RS-485 serial settings (SW1.9 and SW1.10):

• SW1.9 – data signaling rate
  • OFF: 9600 bps (factory default)
  • ON: 19200 bps
• SW1.10 – parity bit
  • OFF: NONE (factory default)
  • ON: EVEN

In order to modify ID number (or Modbus device address), data signaling rate (or baudrate) or parity parameters, a power cycle is needed. To make any change be effective, the process must be as follows:

• configure the desired ID (SW1.1 and SW1.8), baud rate or parity (SW1.9 and SW1.10).
• switch-off the device and wait 5 seconds (any LED might be ON).
• switch-on again the device.

NOTICE

• All the devices belonging to one RS-485 bus must have the same serial settings and the Modbus device address of each Solar SMS cannot be used more than once.
• After modifying any DIP switch setting, the changes need to be applied by powering off and then back on the equipment.
• Regardless of the SW 1.10 parity bit setting there is always ONE stop bit

Recommendations when using serial converters
Solar SMS devices have been designed to operate in PV utility scale and PV rooftop industrial-commercial systems. In this type of installation sites, the Mod-bus RTU client(s) sending requests to the Solar SMS is/are normally:

• A set of PLCs (typically one PLC per inverter shelter) acting as local dataloggers. In this case a Scada software will send Modbus requests to the PLCs instead of to the Solar SMS
• A Scada software located in the control room sends Modbus requests directly to the Solar SMS. In this case the appropriate RS485 masters for the field buses should be used, such as Weidmüller Serial/Ethernet converters, installed in the inverter shelters.

ATTENTION

The RS485 transceiver ICs can be destroyed!
Some Serial/Ethernet converters internally tie the RS485 pin C to their power supply GND. Failure to observe this particularity could permanently destroy the RS485 transceiver ICs.

• Please ensure that there are no ground loops (i.e. different paths to protective earth) in the pin C of the RS485 bus.

Weidmüller provides also equipment for PV Communica-tion boxes that can be used to guarantee the best performance and compatibility of all the electronic equipment in the PV site.
Please contact your Weidmüller sales representative for further information.

In terms of configuration of the Scada or PLC acting as Modbus client please follow these recommendations:

• Set the Modbus client timeout to 1 second.
• The recommended practical polling interval per slave is 20 seconds. This is a good tradeoff between unnecessary network traffic (and database size) and time resolution. Keep in mind that the sun, the clouds and the MPP of the inverter do not change significantly in 20 seconds!
• For the most efficient use of the PV site network bandwidth we recommend that all the Modbus registers of each Solar SMS Master are read in one single, function code 0x04 “read input registers”.
• The averaging window length is 2.5 seconds.

Solar SMS Slaves configuration
All variants of Solar SMS Slave use Modbus RTU protocol in “slave” mode, returning reading data (current measurements) to the “master” (the Solar SMS Master unit) when asked.
The baudrate is fixed at 19200 bps (factory default).
All and each Solar SMS Slave (regardless the variant we do have) are internally connected as a daisy-chain configuration to the Solar SMS Master unit and are equipped with a push-button (SW1) as can be seen in figure 6.6.

The push-button is meant to set the device address of each and all Solar SMS Slave daisy-chained to the Solar SMS Master unit. The push-button must be pressed in the desired order we do want to assign current channels order (8 up to 32).

For doing so, a Modbus address must be given to each module and shown explained below:

• ensure that all Solar SMS Slave units are powered on.
• shortly press the push-button of the first Solar SMS Slave unit to be configured to enter in “waiting address state” (green LED will blink slowly).
• the Solar SMS Master will send a broadcast message with the assigned address number.
• the Solar SMS Slave will save the address in the flash memory.
• the Solar SMS Slave Modbus address is configured and assigned to the unit.

Please repeat the process for all and each Solar SMS Slave daisy-chained to the Solar SMS Master unit.

Note:

• the address assignment is concluded when the process is done within the first 60 seconds after owering on all devices so there are 60 seconds after power is on to assign the address to all and each connected Solar SMS Slave devices.
• to reset the Modbus address of a Solar SMS Slave unit, the push-button must be pressed for 5 seconds. Then, the process for assigning a Modbus address must be followed again.

Solar SMS LED signals
The Solar SMS Master is equipped with two signal LEDs which indicate the system’s status without use of further equipment.
The green LEDs present at Solar SMS Master module provides information about the supply voltage of the unit (LED marked as “M”) and the communications activity with connected Solar SMS Slaves daisy-chained and with the Scada or a PLC/datalogger (LED marked as “S”) as shown in figure below

When the Solar SMS Master is for the first time connected to the voltage supply, both green LEDs (marked as “M” and “S”) turns on indicating that the device is powered on.
If communication between Solar SMS Master and any Solar SMS Slave is stablished, LED marked as “S” start to blink meaning Solar SMS Master is transmitting.
In the same way, when the communication between Solar SMS Master and the Scada or a PLC/datalogger is established, LED marked as “S” starts to blink meaning Solar SMS Master is transmitting.
The Solar SMS Slave is equipped with one signal LED which indicate the system’s status without use of further equipment.
The green LED present at Solar SMS Slave module (on each and all variants possible) provides information about the supply voltage and the internal RS-485 communications activity with Solar SMS Master connected (LED marked as “DL1”) as shown in figure 6.8.
The onboard LED will indicate the communication activity.

When the Solar SMS Slave is for the first time connected to the voltage supply (note: supply voltage will come from Solar SMS Master wiring), the green LED (marked as “DL1”) turns on indicating that the device is powered on. Immediately after, LED marked as “DL1” will start to blink slow meaning Solar SMS Slave has no ID address assigned yet and awaiting to be configured (see section 3.6 Solar SMS Slaves configuration). If communication between Solar SMS Slave and Solar SMS Master is stablished, LED marked as “DL1” starts to blink fast meaning Solar SMS Slave is transmitting and communicating with Solar SMS Master unit.

Recommendations when configuring the SCADA
If you will configurate the Scada or PLC acting as Modbus client please follow these recommendations:

• The Modbus client timeout should be 1 second.

• The practical polling interval per slave should be 20 seconds.
  This is a good tradeoff between unnecessary network traffic (and database size) and time resolution. Keep in mind that the sun, the clouds and the MPP of the inverter do not change significantly within 20 seconds!

• For the most efficient use of the PV site network bandwidth the Modbus registers of each Solar SMS should be read in one single function code 0x04 “read input registers”, request spanning from registers 1 to 35. This request will not create any 0x02 “illegal data address” exception due to the “gaps” in the register table.

• The averaging window length should be 2.5 seconds.

• The system should prove the following measurement and alarm information via Modbus:

  • Averaged PV system voltage
  • Averaged PV current for each input
  • Averaged PCB temperature
  • Status of the digital inputs
  • Alarm flag: PV system under-voltage (user configurable threshold)
  • Alarm flag: Individual input undercurrent (user configurable threshold)
  • Alarm flag: Blown fuse
  • Alarm flag: PCB over temperature (fixed threshold 70 °C)

• When connecting to SCADA please verify the electrical drawings ensuring what string number is connected to what Solar SMS channel. String number one of the Combiner Box may not be connected to channel number 1 of the Solar SMS and thereof. Map the SCADA and the Solar SMS according to the electrical drawings provided with the product in order to obtain the correct current values displayed in the SCADA

Commissioning

Preconditions for the commissioning

• The installation work has been made according to the “Installation” chapter of this user manual.

• The floor around the PV DC COMBINER BOX is firm and easily accessible so that work can be done safe.

  • Wear appropriate clothes and personal protective equipment.

  • Use appropriate tools with the correct insulation.
    A multimeter is necessary in order to verify the absence of voltage in the live parts of the combiner box.

  • Check that the Multimeter is capable to read the maximum voltage of the string and the maximum current before starting.

DANGER
Imminent risk of life!
High voltages up to 1.000 or 1.500 V DC are present in the live parts. Touching live parts can result in death or serious injury due to electric shock.

• Before starting any work in the PV DC COMBINER BOX:
  • disconnect the DC switch
  • ensure that there is no current flowing through the strings.
• Ensure that nobody reconnects the unit while work is not finished or any operator is still working.
• Ensure that no voltage is present in parts that are going to be checked or that could be accessible.
• Do not touch live components.
• If specific live parts cannot be insulated or disconnected, it is mandatory to use additional safety elements to avoid any risk to persons or equipment

Main indications and checks
It is recommended to carry out a general inspection on the PV DC COMBINER BOX and the status of the installation. The installation must comply with either local and interna- tional regulations.
Visual inspection

Check the following issues:

• All cables are in good condition.

• All connections of cables to the terminals are correct.

• There are no hazards around the installation that could create any damage.

• The cables are connected to the correct polarity.

• The enclosure is firmly fixed to the structure, all mount- ing elements are tightened properly.

• The door of the enclosure is properly closed and the seal fits all around the door to provide the insulation. As a check press the door while locking the key-locks a few times.

• The cable glands are tightened correctly.

• If WM4 C connectors are used, they are fixed correctly.

• The grounding cable is connected through its own cable gland and the cable gland is tightened correctly.

• Check the correct status of the SPD. The viewing win- dow should be in green colour.
  Additional inspections issues for the PV DC COMBINER BOX with string monitoring:

• The RS485 wire is correctly connected to the specific terminals inside the combiner box or alternatively to the Solar SMS RS485 connector through its own cable gland.

• The cable gland for communications cable is tightened correctly.

Measurements

DANGER
Imminent risk of life!
High voltages up to 1.000 or 1.500 V DC are present in the live parts. Touching live parts can result in death or serious injury due to electric shock.

• Before starting any work in the PV DC COMBINER BOX:
  • disconnect the DC switch
  • ensure that there is no current flowing through the strings.
• Check the correct polarity of the positive and negative cables of the PV strings with a multimeter.

Startup

DANGER
Imminent risk to life!
Work on live components may only be carried out by qualified electricians.

• Observe the country-specific regulations for working on live components.
• When working on live components, always use suitable tools and aids that eliminate the risk of electric arcs and electric shocks.

Imminent risk of life!
High voltages up to 1.000 or 1.500 V DC are present in the live parts.

• Insert fuses into the fuse holders only if all previous tasks have been finished with sat- isfactory results.
• Use only fuses provided by Weidmüller within each individual PV DC COMBINER BOX.

In case the PV DC COMBINER BOX has been provided without fuses, please use the authorized fuses described in section “Fuses” or contact with your Weidmüller representative for more information.

• Insert the fuses provided with the PV DC COMBINER BOX into the fuse holders using the appropiate tool from Weidmüller (or equivalent appropriated for this activity).
• Switch on the DC disconnection switch (from OFF to ON position)

Additionally for PV DC COMBINER BOX with string monitoring:

• Verify the Solar SMS power LED lights green.
• Verify the Solar SMS DC/DC power supply LED lights green.
• Close and secure the door with the key-tool lock.

Accessories and replacing parts

Some parts of the PV DC COMBINER BOX can be replaced in case of damage. Before proceed with any of these replacements, we highly recommend to contact with your Weidmüller representative to clarify any doubt.

Replacing fuses

| DANGER
---|---
Imminent risk of life!

High voltages up to 1.000 or 1.500 V DC are present in the live parts.

►  Ensure that the product is switched off and that it is free of hazardous voltage (from generator side and from inverter side).

►  Ensure that there is no current flowing through the string before removing fuses. Never remove fuses under load.

►  Use only fuses provided by Weidmüller.

►  Use only the same type of fuse like the ones inserted in the other fuse holder (same model and rate).

• Before replacing fuses, verify that there is no electrical issue active in the circuit which could cause the blowing of the new fuse.
• Verify by visual check, that the fuse holders are free from any damage
• Disconnect the DC switch.

Combiner box with PV connectors:

• Disconnect the PV string cable outside of the combiner box to assure that there is no voltage in the damaged fuse.
• Extract the damaged fuse and insert the new one.

Replacing a switch disconnector
DC switches cannot be replaced easily by operators in the field. If this device is damaged, please contact your Weidmüller representative.

Replacing string monitoring devices
Solar SMS monitoring devices must not be replaced by operators in the field. If this device is damaged, please contact your Weidmüller representative.

Replacing surge protection arresters

| DANGER
---|---
Imminent risk to life!

The contacts in the sockets of the surge pro- tection arresters are live. The system must be switched off for this work.

►  Do not reach into the sockets when the ar- rester is removed.

Weidmüller SPDs have three individual arresters. If the SPD is damaged, the status indicator of the respective arrester will be red.

In order to replace an arrester, proceed as shown below.

Cleaning

ATTENTION
The product can be destroyed!
The enclosure and cover may be damaged by detergents, scouring agents, solvents and high-pressure cleaners.

• Use a cloth moistened with clear water for cleaning.
• Clean the PV DC COMBINER BOX at regular intervals so that the warning symbols are always clearly visible.
• Only clean the exterior of the enclosure when it is closed.
• Take care not to damage the sticker with warning symbols.

Maintenance and Service

Maintenace
The PV DC COMBINER BOX is a product with minimum maintenance.

• Carry out a visual inspection once per year checking the issues listed below.

DANGER
Imminent risk of life!
High voltages up to 1.000 or 1.500 V DC are present in the live parts.

• Ensure that the product is switched off and that it is free of hazardous voltage (from generator side and from inverter side).

Check list for the annual inspection of the PV DC COMBINER BOX

Remarks| Issue| Checked
Enclosure and seals|
Temperature fluctuations on outdoor sites strain the seals.| ►  Check that the cover seals are in proper condition.|
Porous or squeezed seals decrease the tightness and therefore the IP class of the enclosure.| ►  Check that there is no or dust inside the enclo- sure.|
Humidity inside the enclosure can cause corrosion.| ►  Check the seals and screw connections as well as the drainage inserts.

►  Check that there are no signs of corrosion, water or humidity inside the enclosure.

|
Regard the tightening torques in the specific docu- mentation inside each PV DC COMBINER BOX.| ►  Check the cable glands and retighten them if needed.|
Surge protection arresters (optional)|
The inspection windows of the surge arresters should be green.| ►  Replace each surge arrester the inspection win- dow of which is red.|
The PV DC COMBINER BOX has a mark on all screws and nuts to indicate the torque position. If the mark is unchanged since the previous inspection, there is no loss of torque.

Regard the tightening torques in the specific docu- mentation inside each PV DC COMBINER BOX.

| ►  Check if any of the marks on screws and nuts have been changed.

►  Retighten the screws if needed.

|
Fuses|
Blown fuses diminish the yield of the PV plant.| ►  Check the continuity of all fuses.|
DC switch|
The PV DC COMBINER BOX has a mark on all screws and nuts to indicate the torque position. If the mark is unchanged since the previous inspection, there is no loss of torque.

Regard the tightening torques in the specific docu- mentation inside each PV DC COMBINER BOX.

| ►  Check if any of the marks on screws and nuts have been changed.

►  Retighten the screws if needed.

|
Fuse holders|
---|---
Burn marks| ►  Check that there are no burn marks on the termi- nals.|
Measure voltage| ►  Check the voltage of the strings by using the test- ing points in the terminals.|
String monitoring device|
| ►  Check that the device is correctly fixed to the mounting plate with the screws.|
| ►  Check that the LED is working properly according its function.|
DC/DC power supply|
| ►  Check that the device is correctly tightened to the DIN rail.|
The PV DC COMBINER BOX has a mark on all screws and nuts to indicate the torque position. If the mark is unchanged since the previous inspection, there is no loss of torque.

Regard the tightening torques in the specific docu- mentation inside each PV DC COMBINER BOX.

| ►  Check if any of the marks on screws and nuts have been changed.

►  Retighten the screws if needed.

|
General inspection| |
| ►  Check that there are no burn marks on the termi- nals.|

Service
If you have any questions about the
PV DC COMBINER BOX, please contact the Weidmüller representative in your country.
Information about the PV DC COMBINER BOX like videos, installation guides and FAQ’s re provided on the Weid- müller website.

References

• Weidmüller: Smart Industrial Connectivity from Detmold with Love
• Weidmüller: Smart Industrial Connectivity from Detmold with Love
• Weidmüller: Verbindungstechnik from Detmold with Love

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