Fronius GEN24 Plus Hybrid Inverter Instruction Manual

Fronius GEN24 Plus Hybrid Inverter

Product Information

Specifications

• Product Name: Fronius GEN24 Modbus TCP & RTU
• Model Number: 42,0410,2649
• Operating Instructions: DE Bedienungsanleitung EN-US Operating instructions
• Part Number: 030-18102023

Product Usage Instructions

Modbus Protocol
The Fronius GEN24 Modbus TCP & RTU inverter can be used with two different Modbus protocols:

1. Modbus TCP
2. Modbus RTU

Modbus TCP Message Structure
The Modbus TCP message structure consists of the following components:

• ADU (Application Data Unit)
• MBAP (Modbus Application Protocol) Header
• Data
• PDU (Protocol Data Unit)

The MBAP Header includes the following fields:

• Transaction ID (2 Bytes): Used to synchronize request and response
• Protocol ID (2 Bytes): Always set to 0x0000
• Length (2 Bytes): Length of the PDU in bytes
• Unit ID (1 Byte): Address of the device being accessed

It is important to always specify the correct Unit ID, even when the inverter is connected to a single inverter control.

Modbus RTU Message Structure
The Modbus RTU message structure consists of the following components:

• ADU (Application Data Unit)
• Address Field
• Function Code
• Data
• CRC (Cyclic Redundancy Check)

Modbus Function Codes
The Fronius GEN24 Modbus TCP & RTU inverter supports the following Modbus function codes:

• 03 (0x03) Read Holding Registers
• 06 (0x06) Write Single Register
• 16 (0x10) Write Multiple Registers

Exception Codes
In case of an error, the Fronius GEN24 Modbus TCP & RTU inverter may return one of the following exception codes:

• 01: Illegal Function
• 02: Illegal Data Address
• 03: Illegal Data Value
• 04: Slave Device Failure
• 11: Gateway Path Unavailable

Register Maps
The Fronius GEN24 Modbus TCP & RTU inverter uses register maps to store and access data. The available register addresses depend on the specific model and functionality of the inverter.

Usage Examples
Here are some examples of how to use the Modbus function codes with the Fronius GEN24 Modbus TCP & RTU inverter:

Read Holding Registers (Function Code 03)
To read holding registers, send the following request:

• Function Code: 0x03
• Start Address: 0x0000 to 0xFFFF (0 to 65535)
• Number of Registers: 1 to 125

The response will contain the requested register values and the nfunction code 0x03.

Write Single Register (Function Code 06)

To write a single register, send the following request:

• Function Code: 0x06
• Register Address: 0x0000 to 0xFFFF (0 to 65535)
• Register Value

The response will confirm the successful write operation and include the function code 0x06.

Write Multiple Registers (Function Code 16)
To write multiple registers, send the following request:

• Function Code: 0x10
• Start Address: 0x0000 to 0xFFFF (0 to 65535)
• Number of Registers
• Register Values

The response will confirm the successful write operation and include the function code 0x10.

FAQ (Frequently Asked Questions)

• Q: How can I determine the Unit ID for my Fronius GEN24 Modbus TCP & RTU inverter?

• A: The Unit ID is a unique address assigned to each device. You can find the Unit ID in the Modbus settings of your inverter or in the user manual.

• Q: What are the possible exception codes returned by the inverter?
  A: The possible exception codes are:

  • 01: Illegal Function
  • 02: Illegal Data Address
  • 03: Illegal Data Value
  • 04: Slave Device Failure
  • 11: Gateway Path Unavailable

The Modbus Protocol

General

• The description of the protocol is largely taken from the Modbus specifications, which are publicly available at www.modbus.org/specs.php.
• Modbus is a simple, open communication protocol, with which master-slave or client-server communication can be carried out between the devices connected to the network. The basic principle of Modbus is: a master sends a request and a slave responds to this. In Modbus TCP, the master is referred to as the client and a slave as a server. The function is the same. The descriptions of the protocol functions provided below will use the more common names master and slave, irrespective of the RTU and TCP variants. In cases where there are differences between RTU and TCP, this will be specifically indicated.
• Modbus can be used in two ways on the inverter:
  • Modbus TCP using TCP/IP via Ethernet (connected by cable or via WLAN)
  • Modbus RTU using asynchronous serial transmission via RS-485 (EIA/TIA-485-A)
• In the case of Modbus RTU, there can only ever be one master in the system. In principle, only one master may initiate requests. A slave may only give a response if it has been addressed by the master; the slaves cannot communicate with each other. If a broadcast request (request to all available slaves via slave ID or unit ID 0) is sent, none of the slaves can respond. Broadcasts can therefore only be used for write commands.
• If a master sends a request to a slave, then it expects a response. In the event of a request from a master, there are five options:
  • If the slave receives the request without communication errors and can process this request without errors, then a normal response will be sent with the required data.
  • If the slave does not receive the request due to a communication error, then no response is sent. This leads to a timeout on the master.
  • If the slave receives the request, but discovers a communication error (parity, CRC, etc.), then no response is sent. This leads to a timeout on the master.
  • If the slave receives the request without communication errors, but cannot process it without errors (e.g., if a register that is not available needs to be read), then an error message (exception response) is returned with the reason for the error.
  • If the slave receives a broadcast request, which also goes to all other devices, then no response will be sent either in the event of an error or if the request has been successfully processed. Broadcast requests are therefore only suitable for write commands.
• Modbus devices provide data in 16 bit large data blocks (registers).
• In certain cases, individual data points may also cover several data blocks (e.g., 2 registers = 32 bit value).

Structure of Modbus Messages

• In principle, a Modbus message is made up of the protocol data unit (PDU). This is independent of the underlying communication layers.
• Depending on the bus or network that is used, additional fields can also be added. This structure is then referred to as the application data unit (ADU).

PDU Structure of a Modbus message for Modbus RTU

ADU

PDU

• Structure of a Modbus message for Modbus TCP
• Modbus TCP uses its own header to identify the application data unit. This header is called MBAP header (MODBUS application protocol header).
• The size of the protocol data unit (PDU) is limited due to the first Modbus implementations in a serial network (max. RS-485 ADU = 256 bytes). This results in the following for the size of the protocol data unit PDU: PDU = 256 – slave ID
• (1 byte) – CRC (2 bytes) = 253 bytes
• This results in:
  • Modbus RTU ADU = 253 + slave ID (1 byte) + CRC (2 bytes) = 256 bytes
  • Modbus TCP ADU = 253 bytes + MBAP (7 bytes) = 260 bytes

Modbus TCP –MBAP Header

• The MBAP header includes 7 bytes:
  • Transaction ID (2 bytes): Is used in order to synchronize request and response. The slave adopts the transaction ID from the request into the response.
  • Protocol ID (2 bytes): Is always 0 (Modbus protocol).
  • Length (2 bytes): The length field includes the number of bytes of the subsequent fields, including unit ID and data fields.
  • Unit ID (1 byte): This field is used for addressing devices connected to the inverter (gateway function). The unit ID corresponds to the slave ID in Modbus RTU. The value is specified by the master and is returned unchanged by the slave with the response.
• For details about the addressing of the devices, see:
  • Modbus device ID for inverters on page 48
  • Modbus device ID for energy meters on page 49

IMPORTANT! The correct unit ID must always be specified, even if the inverter control is only connected to one individual inverter.

Supported function codes

The function code determines the action to be carried out on the slave. Three function codes for read and write operations are supported:

• 03 (0x03) 1) read holding registers
• 06 (0x06) 1) write single register
• 16 (0x10) 1) write multiple registers

If an error occurs on the slave during the processing of a request, an error message is sent as the response (exception response). In the event of this kind of response, the most significant bit of the function code is set to 1 (corresponds to adding 0x80 to the function code) 1) and an exception code is added, which indicates the reason for the error.

1. The prefix “0x” stands for hexadecimal numbers.

03 (0x03) Read Holding Registers
This function code is used to read the content of one or more successive registers of a device. The request contains the address of the first register to be read and the number of registers to be read. Registers are addressed in the request starting at 0. This means that registers 1 to 16 will be addressed via addresses 0 to 15.

Request

Response

*N = number of registers

Error

06 (0x06) Write Single Register
This function code is used in order to write a single register. The request only contains the address of the register to be written. Registers are addressed starting at 0. This means that register 1 is addressed via address 0. The normal response is a copy of the request, which is sent after successfully writing the register.

Request

Response

Error

16 (0x10) Write Multiple Registers
This function code is used in order to write a block of successive registers. The request contains the address of the first register to be written, the number of registers to be written, the number of bytes to be written, and the values to be written (2 bytes per register). The normal response contains the function code, the start address, and the number of registers written.

Request

*N = number of registers

Response

Error

Exception codes
An error message (exception response) has two fields, which distinguishes it from a normal response:

• Function code field
  In a normal response, the function code of the request is adopted into the function code field of the response. In all function codes, the most significant bit (MSB) is 0 (the values of the function codes are all lower than 0x80). In an error message, the MSB is set to 1. This means that 0x80 is added to the value for the function code. The master can identify the response as an error message due to the set MSB.

• Data field
  A normal response contains data or statistical values in the data field. In an error message, an exception code is returned in the data field. This exception code indicates the reason for the error message.

Modbus exception codes

Code| Name| Meaning
01| ILLEGAL FUNCTION| The function code in the request is not supported by the slave.
02| ILLEGAL DATA ADDRESS| Invalid register addresses have been requested.
Modbus exception codes

Code| Name| Meaning
03| ILLEGAL DATA VALUE| A value in the request is outside of the valid range. This applies both for the fields of a request (e.g., invalid number of registers) and for invalid setting values for the SunSpec inverter control models.
04| SLAVE DEVICE FAILURE| An error occurred during an attempt to write one or more registers.
11| GATEWAY TARGET DEVICE FAILED TO RESPOND| The addressed device is switched off and cannot be found.

CRC Calculation for Modbus RTU

• Each Modbus RTU message is equipped with a checksum (CRC, Cyclic Redundancy Check) in order to be able to identify transmission errors. The size of the checksum is 2 bytes. It is calculated by the sending device and attached to the message to be sent. For its part, the receiver calculates the checksum from all bytes of the received message (without CRC) and compares this with the received checksum. If these two checksums are different, then an error has occurred.

• The calculation of the checksum starts with setting all bits of a 16 bit register
  (CRC register) to 1 (0xFFFF). All bytes of the message are then individually processed with the CRC register. Only the data bytes of one message are used for the calculation. Start, stop, and parity bits are not considered.

• During the calculation of the CRC, each byte is XOR-linked with the CRC register. The result is then moved in the direction of the least significant bit (LSB) and the most significant bit (MSB) is set to 0. The LSB is considered. If the LSB was previously 1, then the CRC register is XOR-linked with a fixed assigned value. If the LSB was 0, then nothing needs to be done.

• This process is repeated until the CRC register has been moved eight times. After the last (eighth) movement, the next byte is taken and XOR-linked to the current CRC register.

• The write process then starts from the beginning; it is again moved eight times. After dealing with all bytes of the message, the value of the CRC register is the checksum.

Calculation algorithm of the CRC16

Calculating CRC Checksum

1. Initialize a 16 bit register (2 bytes) with 0xFFFF. This register is referred to as the CRC16 register.
2. XOR-link the first byte of the message with the less significant byte of the CRC16 register. The result is saved in the CRC16 register.
3. Move the CRC16 register 1 bit to the right (in the direction of the LSB), fill MSB with 0. Look at LSB.
4. Check LSB value
5. If the LSB was 0: Go to step 3 (move again).
6.  If the LSB was 1: XOR-link the CRC16 register with the CRC polynomial 0xA001 (1010 0000 0000 0001).
7. Repeat steps 3 and 4 until eight movement operations have been carried out. When these have been carried out, a complete byte of the message will have been processed.
8. Repeat steps 3 to 5 for the next byte of the message. Repeat everything until all bytes of the message have been processed.
9. After the last byte, the CRC16 register contains the checksum.
10. When the checksum is added to the message to be sent, then the two byes must be inverted as described below.

Adding CRC Checksum to the Message
If the 16 bit (2 bytes) CRC checksum is sent with a message, then the less significant byte is transferred before the more significant one.
For example, if the CRC checksum is 0x1241 (0001 0010 0100 0001):

Addr| Func| Data Count| Data| Data| Data| Data| CRC

Lo

| CRC

Hi

---|---|---|---|---|---|---|---|---

General

Abbreviations Used

Inverter

SID

Identification as a SunSpec device

Common Block

Device information

Inverter Model

Inverter data

Nameplate Model
Basic Settings Model
Ext. Measurement Model
Immediate Controls Model
Multi. MPPT Inv. Ext. Model
Basic Storage Control
End Block

Energy meter

SID

Identification as a SunSpec device

Common Block

Device information

Meter Model

Energy meter data

End Block

The register lists can be downloaded from the Fronius website: https://www.fronius.com/de/downloads/SolarEnergy/Modbus Sunspec Maps, State Codes and Events

Response times

Recommendation for timeout values
Modbus requests should only be executed sequentially and not in parallel (maximum 2 queries in parallel). Perform the requests with a timeout of at least 1 second. Requests in millisecond intervals can lead to long response times. Multiple register requests in one message are faster than multiple requests of individual registers.

Modbus device ID for inverters

• TCP: The unitid of the inverter is always 0x01. Identification is possible by the IP address.
• RTU: The slaveid must be configured on the web interface of the GEN24. Several GEN24 devices can be connected together. Each device must have a unique number.

Modbus device ID for energy meters
If an energy meter (e.g., Fronius Smart Meter 63A) is connected via Modbus RTU, it can be read out via the settable Modbus device ID using Modbus TCP.

Fronius Smart Meter address          Modbus device ID

1                                                       200 (default)

2                                                       201

3                                                       202

4                                                       203

5                                                       204

Register addresses

IMPORTANT!

• Register addresses do not remain constant.
• The actual register addresses depend on the composition of the dynamic SunSpec register list.

Correct procedure:

• Search for the model by making a request (determine start address)
• Then work with offsets

To read a register, the register’s start address must be specified in the Modbus request.

SunSpec Basic Register: 40001
Registers begin at 1 and do not represent a function code.

• Do not confuse the registers with the Modicon address scheme: in the Modicon address scheme, 40001 is displayed as 4×40001. To read register 40001, use address 40000 (0x9C40).
• The register address that is output therefore always has 1 number less than the actual register number.

IMPORTANT!

• The lengths of individual models may vary due to the data types used.
• Start addresses are therefore specified for SunSpec models in the case of some register tables.
• This start address, together with the offset from the table, then produces the value of the actual register number.
• Example: Table Nameplate Model (120) on page 59: the register WRtg of the Nameplate Model has an offset of 4. The start address is specified as 40131 with the setting “float”.
• Therefore, the correct register number is: 40131 + 4 = 40135.

Examples for Modbus RTU:

Request for 4 registers starting from register 40005 (Mn, Manufacturer)
Send (bytes in hexadecimal)

Low      High

byte     byte

Receive (bytes in hexadecimal)

“F” and “r”

| Address 40006

“o” and “n”

| Address 40007

“i” and “u”

| Address 40008

“s” and 0

| Checksum Low     High

byte    byte

Enter one register starting from register 40242 (WmaxLimPct)

Checksums “i” and “u”
| | | | Low      High

byte     byte

Examples for Modbus TCP:

.Request for 4 registers starting from register 40005 (Mn, Manufacturer)
Send (bytes in hexadecimal)

Receive (bytes in hexadecimal)

Address 40005

“F” and “r”

| Address 40006

“o” and “n”

| Address 40007

“i” and “u”

| Address 40008

“s” and 0

Enter one register starting from register 40242 (WmaxLimPct)

Number of registers entered

Unavailable data records
Fronius inverters cannot always provide all the data specified in the SunSpec data models. Depending on the data type, this data is represented by the fol- lowing values in accordance with the SunSpec specification:

• int16 (-32767 to 32767): 0x80001)
• uint16 (0 to 65534): 0xFFFF
• acc16 (0 to 65535): 0
• enum16 (0 to 65534): 0xFFFF
• bitfield16 (0 to 0x7FFF): 0xFFFF
• pad (0x8000): always 0x8000
• int32 (-2147483647 to 2147483647): 0x80000000
• uint32 (0 to 4294967294): 0xFFFFFFFF
• acc32 (0 to 4294967295): 0
• enum32 (0 to 4294967294): 0xFFFFFFFF
• bitfield32 (0 to 0x7FFFFFFF): 0xFFFFFFFF
• int64 (-9223372036854775807 to 9223372036854775807): 0x8000000000000
• uint64 (0 to 18446744073709551615): 000
• acc64 (0 to 18446744073709551615): 0xFFFFFFFFFFFFF
• stringX: FFF
• float32 (range see IEEE 754): 0
• sunssf (scale factors; -10 to 10): all X registers filled with 0x0000

1. The prefix “0x” stands for hexadecimal numbers

NOTE!

• Data points that are not supported are marked with “Not supported” in the “Range of values” column in the register tables.
• In this case, during reading, the corresponding value from the list above is obtained depending on the data type.
• In certain instances, registers which are basically listed as supported may also return this value. This is because some values depend on the device type, e.g., currents AphB and
• AphC in the case of a singlephase inverter.

Time response of the supported operating modes 1) The prefix “0x” stands for hexadecimal numbers Time response illustrated by power reduction

• The inverter’s time response in an operating mode can be defined by several time values.
• Three possible time values are shown in the figure “Time response illustrated by power reduction”:
• WinTms 0–300 [seconds]
  • Specifies a time window in which the operating mode is randomly started. The time window starts when the start command for the operating mode is issued (e.g., OutPFSet_Ena = 1).
  • WinTms can be used to prevent all the inverters in the system from applying the changes at the same time. If the time window is set to 0 (the default va-lue), the operating mode will start immediately.
• RvrtTms 0–28800 [seconds]
  • Determines how long the operating mode will remain active. The timer is restarted with every Modbus message received. If no new Modbus message was received during the fallback time (= RvrtTms), the operating mode is automatically ended and the operating mode with the next highest priority becomes active, e.g., dynamic power reduction.
  • If RvrtTms is 0 (the default value), the operating mode remains active until it is manually deactivated via the corresponding register. In this instance the fallback option is not available.
• RmpTms
  • Specifies how quickly the changes are to be made. The corresponding value gradually changes during the specified time period from the old to the new value.
  • If RmpTms is 0 (the default value) or if this value is not supported, the new value will be valid immediately.

Sign Convention for the Power Factor The EEI sign convention1) for the power factor is in line with the SunSpec specification and is based on the information contained in the “Handbook for Electricity Metering” and IEC 61557-12 (2007).

The power factor is:

• negative if the reactive power is positive (overexcited, quadrant 1)
• positive if the reactive power is negative (underexcited, quadrant 4)

EEI = Edison Electrical Institute

• Values saved on the card

Nameplate Model (IC120):

• WRtg
  AC nominal output of inverter

• VARtg
  AC nominal apparent output of inverter.
  Default value = WRtg

• VArRtgQ1
  Maximum AC reactive power in the first quadrant (over-excited).
  Default value is calculated based on the available cos Phi (0.85) and the nominal apparent power. Note the scale factor VArRtg_SF

• VArRtgQ4
  Maximum AC reactive power in the fourth quadrant (underexcited). Default value is calculated based on the available cos Phi (0.85) and the nominal apparent power. Note the scale factor VArRtg_SF

• ARtg
  AC nominal current of inverter

Basic Settings Model (IC121):

• WMax
  Maximum AC power
  Default value = WRtg

• VRef
  Reference voltage at the feedin point

• VRefOfs
  Deviation from reference voltage

• VMax
  Maximum AC voltage

• VMin
  Minimum AC voltage

• VAMax
  Maximum AC apparent power Default value = VARtg

Scale factors

• IMPORTANT! Scale factors (also possible when selecting “Float”!) are not static, even if they are entered as a fixed value in these Operating Instructions.
• Scale factors can change every time the firmware is changed and also change with the runtime (autoscale) (e.g., scale factor for power specification).
• Scale factors with constant values are listed in the tables in the column “Range of values”.
• Current data (data of inverters and energy meters) may have variable scale factors. These must be read from the corresponding registers.
• The data type “sunssf” is a signed integer with 16 bits.
• Example calculation:
• (Model 160): 1_DCW = 10000, DCW_SF = -1 -> Power = 10000 x 10^(-1) = 1000 W

Non-writable registers
The following registers cannot be written:

• Read-only (R) registers
• Registers which are currently not supported

NOTE!

• If an attempt is made to write to such registers, the inverter does not return an exception code!
• The values written to these registers are ignored without an error message.
• In Model 123 and 124, an exception occurs during write access if the control option in the local web interface has been deactivated.

Entering Invalid Values

• Some registers only permit certain values. The valid values can be found in the relevant register table.
• If an invalid value is entered into a register, the inverter control will return exception code 3 (illegal data value). The invalid value is ignored.

Modbus Settings

General
From your web browser, you can use the inverter web interface to apply the Modbus connection settings which cannot be accessed via the Modbus protocol.\

Open the Modbus settings

1. Open the web interface of the inverter
2. Select the “Communication” section (1)
3. Open the “Modbus” menu item (2)

Modbus

• Modbus RTU interface 0 / 1
• If one of the two Modbus RTU interfaces is set to Slave, the following input fields are available:

1. “Baud rate”
   The baud rate influences the transmission speed between the individual components connected in the system. When selecting the baud rate, ensure that it is the same at both the sending and receiving end.

2. “Parity”
   The parity bit can be used to check the parity. It detects transmission errors. A parity bit can safeguard a specific number of bits. The value (0 or

1. of the parity bit must be calculated by the sender and is checked by the recipient using the same calculation. The parity bit can be calculated for even and odd parity.

3. “SunSpec Model Type”

4. Depending on the SunSpec model, there are two different settings.

5. float: SunSpec Inverter Model 111, 112, 113 or 211, 212, 213.

6. int + SF: SunSpec Inverter Model 101, 102, 103 or 201, 202, 203.

7. “Meter address”
   The value entered is the identification number (Unit ID) assigned to the meter.Can be found on the user interface of the inverter in the “Communication” “Modbus” menu. Factory setting: 200

8. “Meter address”
   The value entered is the identification number (Unit ID) assigned to the meter. Can be found on the user interface of the inverter in the “Communication”

9. “Modbus” menu.

10. Factory setting: 1

11. Slave as Modbus TCP

12. If the function “Slave as Modbus TCP” is activated, the following input fields are available:

13. “Modbus port”
    Number of the TCP port that is to be used for Modbus communication.

14. “SunSpec Model Type”

15. Depending on the SunSpec model, there are two different settings.

16. float: SunSpec Inverter Model 111, 112, 113 or 211, 212, 213.

17. int + SF: SunSpec Inverter Model 101, 102, 103 or 201, 202, 203.

18. “Meter address”
    The value entered is the identification number (Unit ID) assigned to the meter.Can be found on the user interface of the inverter in the “Communication”
    “Modbus” menu. Factory setting: 200

19. “Meter address”
    The value entered is the identification number (Unit ID) assigned to the meter. Can be found on the user interface of the inverter in the “Communication”

20. “Modbus” menu.
    Factory setting: This value is invariably defined as 1.
    Inverter control via Modbus
    If this option is activated, the inverter is controlled via Modbus. Inverter control includes the following functions:

21.  on/off

22. Power reduction

23. Specification of a constant power factor (cos phi)

24. Specification of a constant reactive power value

25. Battery control specifications with battery

Limiting control

The “Limit Control” option is only available for the TCP transmission protocols. It is used to block inverter control commands from unauthorized users by only permitting control for specific devices.

Limit Control
If this option is activated, only certain devices will be able to send control commands.

IP address
To limit inverter control to one or more devices, enter the IP addresses of the devices which are permitted to send commands to the inverter in this field. Multiple entries are separated by commas.

Examples:

• One IP address: 98.7.65.4
• Control only permitted by IP address 98.7.65.4
• Several IP addresses: 98.7.65.4,222.44.33.1
• Control only permitted by IP addresses 98.7.65.4 and 222.44.33.1
• IP address range, e.g., from 98.7.65.1 to 98.7.65.254 (CIDR notation): 98.7.65.0/24
• Control only permitted by IP addresses 98.7.65.1 to 98.7.65.254

Common & Inverter Model

Common Block Register

• The description of the Common Block including the SID register (register 40001–40002) for identification as a SunSpec device applies for each device type (inverter, energy meter). Each device has its own Common Block, which lists information about the device (model, serial number, SW version, etc.).
• The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .

Inverter Model Register

• Two different SunSpec models are supported for the inverter data:
  •  the default set inverter model with floating point display (setting “float”; 111, 112 or 113)
  • the inverter model with integers and scale factors (setting “int+SF”; 101, 102 or 103)

The register number of the two model types is different!
The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024  .

SunSpec Opera-ting Codes

• Inverter model register

Nameplate Model (120)

• General
  This model corresponds to a rating plate. The following data can be read:

  • DERType (3)
    Type of device. The register returns the value 4 (PV device).

  • WRtg (4)
    Nominal power of inverter.

  • VARtg (6)
    Nominal apparent power of inverter.

  • VArRtgQ1 (8) – VArRtgQ4 (11)
    Nominal reactive power values for the four quadrants.

  • ARtg (13)
    Nominal current of inverter.

  • PFRtgQ1 (15) – PFRtgQ4 (18)
    Minimal power factor values for the four quadrants.

Nameplate Register

Start address:

• for “float” setting: 40131
• for “int+SF” setting: 40121

The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .

Basic Settings Model (121)

• Basic Settings Register
  • Start address:
  •  for “float” setting: 40159
  • for “int+SF” setting: 40149

The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .

Reference Voltage

VRef (4)

• The reference voltage is the voltage at the joint connection point where the local grid is connected to the public grid. The reference voltage is the same as the inverter’s nominal voltage.
• => See figure “Joint Connection Point.”
• The value is given in volts in the range of 0 (0x0000) to 400 (0x0190).

Joint Connection Point

Deviation from reference voltage

VRefOfs (5)
Depending on the wiring of the local grid, there may be a deviation from the reference voltage at the point where each individual inverter is connected to the local grid (see “Joint connection point” diagram).

Extended Measurements & Status Model (122)

General
This model provides some additional measurement and status values which the normal inverter model does not cover:

• PVConn (3)
  This bit field displays the inverter’s status

• Bit 0: Connected

• Bit 1: Responsive

• Bit 2: Operating (inverter feeds energy in)

• ECPConn (5)

This register displays the status of connection to the grid

• ECPConn = 1: inverter is currently feeding power into the grid
• ECPConn = 0: inverter is not feeding power into the grid
• ActWH (6–9)

Active energy meter

• StActCtl (36–37)
  Bit field for currently active inverter modes

• Bit 0: power reduction (FixedW; corresponds to WMaxLimPct specification)

• Bit 1: constant reactive power specification (FixedVAR; corresponds to VArMaxPct)

• Bit 2: specification of a constant power factor (FixedPF; corresponds to OutPFSet)

• TmSrc (38–41)

Source for the time synchronization, the register returns the string “RTC”

• Tms (42–43)

Current time and date of the RTC
The seconds are specified from January 1, 2000 00:00 (UTC) to the current time.

• Ris
  Iso Resistance

Extended Measurements & Status Register

• Start address:
  • for “float” setting: 40191
  • for “int+SF” setting: 40181

The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .

Immediate Control Model (123)

General

The immediate controls can be used to make the following settings on the inverter:

• deactivation of inverter’s grid power feed operation (standby)
• constant reduction of output power
• specification of a constant power factor
•  specification of a constant relative reactive power

In the settings on the inverter’s web interface, the setting “Inverter control via Modbus” must be enabled under Modbus for write functions to be possible. Depending on the control priority that has been set (IO control, dynamic power reduction, or control via Modbus), Modbus commands may not be accepted.

Immediate Controls Register

• Start address:
  • for “float” setting: 40237
  • for “int+SF” setting: 40227
  • The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .

Standby

• Conn_WinTms (3) to Conn (5)
  These registers are used to control the standby mode (no grid power feed operation) of the inverter.

• Conn_WinTms (3) and Conn_RvrtTms (4)
  These registers can be used to control the inverter’s time response. => See section “Time Response of the Supported Operating Modes”.
  0 is set as the default for all registers.

• Conn (5)
  Register Conn indicates whether or not the inverter is currently feeding power into the grid (0 = standby, 1 = grid power feed operation).

  • In order to switch the inverter to standby, enter the value 0 into this register.
  • In order to reactivate the inverter, enter the value 1 into this register.

NOTE!
To find out whether or not the inverter is feeding power into the grid, you can also use the ECPConn register and check the extended measurements and status model.

Power reduction

• WMaxLimPct (6) to WMaxLim_Ena (10)
  These registers can be used to set an output power reduction in the inverter.

• WMaxLimPct (6)
  Values between 0% and 100% can be entered in register WMaxLimPct.
  The values limit the maximum possible output power of the device, and therefore do not necessarily have an effect on the current power.

IMPORTANT! Observe the scale factor for this register.

Further information can be found at:http://sunspec.org/wp- content/uploads/2015/06/SunSpec-Information-Mo-dels-12041.pdf

• WMaxLimPct_WinTms (7), WMaxLimPct_RvrtTms (8)
• These registers can be used to control the inverter’s time response for this operating mode. => See section “Time response of the supported operating modes”. 0 is set as the default for all registers.
• WMaxLim_Ena (10)
  • Used to start and end this operating mode
  • Enter value 1 into register WMaxLim_Ena = start operating mode
  • Enter value 0 into register WMaxLim_Ena = end operating mode

NOTE!

To change values in an active operating mode (e. g. to set a different power limit or a different return time), proceed as follows:

• Enter the new value into the relevant register
• Restart the operating mode using register WMaxLim_Ena by setting a 1

Example: setting a power reduction

• If you are working with function code 0x10 (write multiple registers), performance specifications can be used to achieve a higher level of performance. Instead of using two

• Modbus commands, it is now possible to preset both the power and enable at the same time with just one command. All 5 registers
  (WMaxLimPct, WMaxLimPct_WinTms, WMaxLimPct_RvrtTms, WMaxLimPct_RmpTms, WMaxLim_Ena) can be written with one command. Writing to the “Read Only” register WMaxLimPct_RmpTms takes place without returning an otherwise usual exception (error) code.

• For example, register values for 80% specification without timing specification: 8000, 0, 0, 0, 1

• Enter the value for the output power reduction in register WMaxLimPct (e.g., 3000 for 30%).

• As an option, you can set the start and return time using registers WMaxLimPct_WinTms and WMaxLimPct_RvrtTms.

• Start the operating mode by entering 1 in register WMaxLim_Ena.

IMPORTANT! Observe the scale factor for this register.
Further information can be found at: http://sunspec.org/wp- content/uploads/2015/06/SunSpec-Information-Mo-dels-12041.pdf

• Example: Changing the Return Time When Power Reduction Has Been Activated
• If the power reduction was originally started using WMaxLimPct_RvrtTms = 0, the operating mode must be manually deactivated.

Set WMaxLimPct_RvrtTms to 30, for example
Apply the change by entering 1 in register WMaxLim_Ena

• The operating mode is automatically deactivated after 30 seconds and the mode with the next highest priority becomes active (e.g., dynamic power reduction)

Effects of reactive power specifications on effective power

• In principle, reactive power operation is limited by the maximum output current (the maximum apparent power) and by the operative reactive power limit of the inverter:
  the following diagram shows the possible working range of the inverter. All valid operating points defined by effective power P and reactive power Q are within the gray area.

• The maximum values must be read out from the Nameplate Model via registers VArRtgQ1 to VArRtgQ4 and VArRtg_SF.

Reactive power and power factor

• Key :
  • W Power
  • VArmax Nominal reactive power
  • Wmax Nominal power
  • VAr Reactive power
  • VArrel Relative reactive power (VAr/VArmax)

Constant power factor

• OutPFSet (11) to OutPFSet_Ena (15)
• These registers can be used to set a constant power factor in the inverter.
• OutPFSet (11)
  • In register OutPFSet it is possible to enter both positive and negative values for the power factor.
  • The values must be scaled up by the factor in register OutPFSet_SF.
  • The lowest possible values depend on the inverter type and can be found in the Nameplate Model.

NOTE!
The power factor value must be entered with the correct sign, see section “Sign convention for the power factor”

• positive for underexcited
• negative for overexcited.

OutPFSet_WinTms (12), OutPFSet_RvrtTms (13)
These registers can be used to control the inverter’s time response for this operating mode. => See section “Time response of the supported operating modes”. 0 is set as the default for all registers.

OutPFSet_Ena (15)
Used to start and end this operating mode

• Enter value 1 into register OutPFSet_Ena = start operating mode
•  Enter value 0 into register OutPFSet_Ena = end operating mode.

NOTE!

Proceed as follows to change values when an operating mode is active (e.g., when setting a different power factor or return time):

• Enter the new value into the relevant register
• Restart the operating mode using register OutPFSet_Ena by setting a 1.

OutPFSet_RmpTMS
–

Example: Setting a Constant Power Factor

• Enter the power factor value in register OutPFSet (e.g., 950 for 0.95).
• As an option, you can set the start and return time using registers OutPFSet_WinTms and OutPFSet_RvrtTms.
• Start the operating mode by entering 1 in register OutPFSet_Ena.

Constant relative reactive power

• VArMaxPct (17) to VArPct_Ena (23)
  These registers can be used to set on the inverter a constant value for the reactive power to be produced by the inverter.

• VArMaxPct (17)

  • Used to set a value for constant reactive power.
  • The minimum and maximum limits depend on the type of inverter.

NOTE!

• In practical operation, the reactive power that is actually available is specified by the inverter’s operating limits.
• For this reason, the reactive power specification can only be reached if enough effective power is fed into the grid.
• If too little effective power is fed into the grid, the inverter will operate at its operating limit.

VArPct_WinTms (19), VArPct_RvrtTms (20)
These registers can be used to control the inverter’s time response for this operating mode. => See section “Time response of the supported operating modes”. 0 is set as the default for all registers.

VArPct_Mod (22)

• This register cannot be changed.
• It returns the (currently) supported operating mode.

Reactive power as a percentage of the maximum possible reactive power.

VArPct_Ena (23)
Used to start and end this operating mode

• Enter value 1 into register VArPct_Ena = start operating mode
• Enter value 0 into register VArPct_Ena = end operating mode.

NOTE!

To change values in an active operating mode (e. g. to set a different reactive power or a different return time), proceed as follows:

• Enter the new value into the relevant register
• Restart the operating mode using register VArPct_Ena by setting a 1.

VArPct_RmpTms (23)
the relative approximation value in %/s

Example: Setting Constant Reactive Power

• Enter the relative reactive power value in register VArMaxPct (e.g., 80 for 80%).
• As an option, you can set the start and return time using registers VArPct_WinTms and VArPct_RvrtTms.
• Start the operating mode by entering 1 in register VArPct_Ena.

Multiple MPPT Inverter Extension Model (160)

General

• The Multiple MPPT Inverter Extension Model contains the values of the DC inverter inputs.
• If the inverter has several DC inputs, then this is where the current, voltage, power, energy, and status codes for the individual inputs are listed. In the inverter model (101–103 or 111–113), only the full DC power of both inputs is output in this case. DC current and DC voltage are displayed as “not implemented”.
• The number of blocks is automatically adjusted based on the DC inputs. For devices with a storage solution, there are two additional blocks (charging (MPP3) and discharging (MPP4)). The register addresses are shifted in the following models (absolutely related to the register addresses).

Multiple MPPT Inverter Extension Register

• Start address:
  • for “float” setting: 40263
  • for “int+SF” setting: 40253

The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .

Basic Storage Control Model (124)

General

• This model is only available for inverters with a storage solution.
• The Basic Storage Control Model can be used to make the following settings on the inverter:
  • Setting a power window within which the charge/discharge capacity of the energy storage may fluctuate.
  •  Setting a minimum charge level that the energy storage must not fall below.
  • Permitting/preventing grid charging of the energy storage.

NOTE!

• All specifications are to be considered recommendations.
• The inverter may deviate from the specifications if this is necessary for operational safety reasons.

Information Provided

The Basic Storage Control Model provides the following read-only information:

• WChaMax

  •  If energy storage is available, this register feeds back the baseline value for the registers OutWRte and InWRt.

• WChaMax := max(MaxChaRte, MaxDisChaRte)

  • If energy storage is not available, the register feeds back a value of 0.

• ChaState

  • Energy storage charge level in %:
  • Estimated_Capacity_Remaining [Wh] / Estimated_Capacity_Maximum [Wh]

• ChaSt
  Energy storage operating status

  • OFF: Energy storage is not available
  • EMPTY: Energy storage is currently fully discharged
  • DISCHARGING: Energy storage is in the process of being discharged
  • CHARGING: Energy storage is in the process of being charged
  • FULL: Energy storage is currently fully charged
  • HOLDING: Energy storage is currently neither charged nor discharged
  • TESTING: used during calibration or service charge

Power Window Specifications

• In the settings on the inverter’s web interface, the setting “Inverter control via Modbus” must be enabled under Modbus for write functions to be possible. Depending on the control priority that has been set (IO control, dynamic power reduction, or control via Modbus), Modbus commands may not be accepted.
• The following examples assume that WchaMax = 3300 W.
• The following applies for the resulting power windows:

Negative power values indicate that the energy storage is charging
Positive values indicate that the energy storage is discharging

NOTE!
The values in the following examples must be scaled according to their scale factors in the specified scale registers after reading and before writing. Manipulating the registers InWRte, OutWRte and StorCtl_Mod will generate changes in the battery status in Fronius Solar.web, ex: Forced Recharge and Energy saving mode, depending on user settings and current status of the battery.

Example 1: Only permit energy storage charging
This behavior can be achieved by limiting the maximum discharge capacity to 0%=> results in window [-3300 W, 0 W]

• OutWRte = 0% (set discharge limit of WchaMax to 0%)
• StorCtl_Mod = 2 (activates discharge limit, bit pattern: 10)
• InWRte is not relevant in this case

Example 2: Only permit energy storage discharging
This behavior can be achieved by limiting the maximum charge capacity to 0% => results in window [0 W, 3300 W]

• InWRte = 0% (set charge limit of WchaMax to 0%)
• StorCtl_Mod = 1 (bit 1 activates charge limit, bit pattern: 01)
• OutWRte is not relevant in this case

Example 3: Do not permit charging or discharging
This behavior can be achieved by limiting the maximum charge capacity to 0%and the maximum discharge capacity to 0%
=> results in window [0 W, 0 W]

• InWRte = 0% (set charge limit of WchaMax to 0%)
• OutWRte = 0% (set discharge limit of WchaMax to 0%)
• StorCtl_Mod = 3 (activate both limit values, bit pattern: 11)

Example 4: Charging and discharging with maximum 50% of the nominal power
This behavior can be achieved by limiting the maximum charge capacity to 50%and the maximum discharge capacity to 50%
=> results in window [-1650 W, 1650 W]

• InWRte = 50% (set charge limit of WchaMax to 50%)
• OutWRte = 50% (set discharge limit of WchaMax to 50%)
• StorCtl_Mod = 3 (activate both limit values, bit pattern: 11)

Example 5: Charging in the range of 50% to 75% of the nominal power
This behavior can be achieved by limiting the maximum charge capacity to 75%and the maximum discharge capacity to -50%
=> results in window [1650 W, 2475 W]

• InWRte = 75% (set charge limit of WchaMax to 75%)
• OutWRte = -50% (set discharge limit of WchaMax to -50%)
• StorCtl_Mod = 3 (activate both limit values, bit pattern: 11)
• Battery status in Fronius Solar.web will change to Forced Recharge

Example 6: Discharging with 50% of the nominal power
This behavior can be achieved by limiting the maximum charge capacity to -50%and the maximum discharge capacity to 50%
=> results in window [-1650 W, -1650 W]

• InWRte = -50% (set charge limit of WchaMax to -50%)
• OutWRte = 50% (set discharge limit of WchaMax to 50%)
• StorCtl_Mod = 3 (activate both limit values, bit pattern: 11)

Example 7: Charging with 50% to 100% of the nominal power
This behavior can be achieved by limiting the maximum discharge capacity to

• 50% => results in window [1650 W, 3300 W]
• OutWRte = -50% (set discharge limit of WchaMax to -50%)
• StorCtl_Mod = 2 (activates discharge limit, bit pattern: 10)
• InWRte is not relevant in this case
• Battery status in Fronius Solar.web will change to Forced Recharge

Setting the Minimum Charge Level

• By setting register MinRsvPct, a minimum state of charge of the energy storage can be set.
• For example, by setting MinRsvPct to 20%, a reserve of 20% of the state of charge can be reserved that the state of charge should not fall below.

Charging the energy storage via the grid

• The ChaGriSet register can be used to allow or prevent inverter storage charging via the grid. The register ChaGriSet and the field “battery charging from DNO grid” in the Fronius system monitoring settings are AND-linked (Device configuration – Components – Battery). If the behavior is to be controlled by the ChaGri-Set flag, “battery charging from DNO grid” must be checked.
• The battery can be woken from standby mode via the IC124 model. If the So-cMin under the last known SoC is set while the battery is in standby mode, this will be enabled.

Basic Storage Controls Regis-ter

Start address:

• for “float” setting: 40313
• for “int+SF” setting: 40303

The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .

1. Register manipulation and Battery status changes in Fronius Solar.web
2. Fronius Solar.web allow users to visualize status changes from the battery. These changes can be seen in Fronius Solar.web under the option Energy balance then Production or
3. Consumption. The changes are marked with a bubble status, clicking on a state change will show the previous state followed by an arrow and the new state.

• Battery state change from Startup to Normal Operation.
• Battery status changes are triggered during normal operation (when the battery is ready to enter in operation, security reasons,etc) or by manipulating the mod-bus registers
• MinRsvPct, InWRte, OutWRte and StorCtl_Mod.

The changes could be triggered as follows:

• A minimum state of charge is set using the register MinRsvPct, the corresponding state change is “Energy-saving mode”.
• Setting the registers InWRte, OutWRte, StorCtl_Mod the battery status could change to “Forced Recharge”.

Meter Model

Meter Model Register

• The data of an energy meter connected with the inverter control via Modbus RTU can be read by the relevant SunSpec models via Modbus TCP.
• In a similar way to the inverter models, there are also two different SunSpec models in this case:
  •  the meter model with floating point display (setting “float”; 211, 212 or 213)
  •  the meter model with integers and scale factors (setting “int+SF”; 201, 202 or 203)

The register number of the two model types is different!

• The Modbus device ID of the energy meter is configurable (default = 200).
• The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .
• There are 4 different meter locations, which are described by the location number (see table). Depending on where the Smart Meter is located and whether the inverter is producing or consuming, the signs of the PowerReal values and the Energy values change. These are shown in the following table:

Meter_Loca- tion|

0 (grid)

|

1 (load)

| 3 (ext. gene- rator)| 256-511

(subload)

---|---|---|---|---
PowerRe-| consuming| producing| generation| load is produ-
al_P_Sum (+| from grid| power| | cing power
positive)| | | |
PowerRe-| feeding in to| normal con-| consumption| normal con-
al_P_Sum (-| grid| sumption| | sumption
negative)| | | |
energy plus| import from| producing| generation =| producing
(absolute| grid = energy| power = en-| energy produ-| power = en-
counter)| consumed| ergy produ-| ced| ergy produ-
| | ced| | ced
energy minus| export to grid| consumption| consumption| consumption
(absolute| = energy pro-| = energy con-| = energy con-| = energy con-
counter)| duced| sumed| sumed| sumed

*is not typically. May occur when other power generation is located in load path and producing more power than load can consume.

End Block

• General Two registers according to the last data model indicate that no further SunSpec models will follow.
• The addresses of these two registers are different depending on the device type (inverter, String Control, energy meter) and selected data type (“float” or “int +SF”).
  •  Inverter:
  • Start address for setting “float”: 40313
  • Start address for setting “int+SF”: 40303
•  Fronius String Control:
• Start address: 40127
• Energy meter:
• Start address for setting “float”: 40195
• Start address for setting “int+SF”: 40176

End Block The register tables can be found on the Fronius website or opened using the link: http://www.fronius.com/QR-link/0024 .

Fronius International GmbH

• FroniusstraBe 1
• 4643 Pettenbach
• Austria
• contact@fronius.com
• www.fronius.com
• At www.fronius.com/contact you will find the contact details of all Fronius subsidiaries and Sales & Service Partners.

References

• fronius.com/QR-link/0024
• Download Suche - Fronius

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