ModbusX class | Top

ModbusX Modbus RTU/ASCii/TCP Client (Master) Since R2019b Description A ModbusX object represents a Modbus Master in the same Modbus network. After creating the object, use dot notation to call methods. With the help of hardware "Modbus dual Masters Adaptor adaptor" from Dafulai Electronics, you can access Modbus RTU/ASCii Servers or Modbus TCP Servers. Compared with Matlab built-in modbus object, our ModbusX supports user defined Function Code. And every method has Error Code return, so you can know modbus exception code. Almost all methods are compatible with Matlab built-in modbus object. Furthermore, we provide Simulink blocks library for ModbusX We supports Modbus ASCii, please use ConfigTool.exe PC software to configure physical bus feature before using ModbusX. Creation Syntax m = ModbusX(Transport,DeviceAddress) m = ModbusX(Transport,DeviceAddress,Port) m = ModbusX(Transport,DeviceAddress,Name,Value) m = ModbusX(Transport,Port) m = ModbusX(Transport,Port,Name,Value) Description example m = ModbusX(Transport,DeviceAddress) constructs a Modbus object, m, over the transport type Transport using the specified DeviceAddress.When the transport is 'tcpip', DeviceAddress must be specified as the second argument. DeviceAddress is the IP address or host name of the Modbus server.. m = ModbusX(Transport,DeviceAddress,Port) additionally specifies Port. When the transport is 'tcpip', DeviceAddress must be specified. Port is the remote port used by the Modbus server. Port is optional, and it defaults to 502, which is the reserved port for Modbus. m = ModbusX(Transport,DeviceAddress,Name,Value) specifies additional options with one or more name-value pair arguments using any of the previous syntaxes. For example, you can specify a timeout value. The Timeout property specifies the waiting time to complete read and write operations in seconds, and the default is 1.1. m = ModbusX(Transport,Port) constructs a Modbus object m over the transport type Transport using the specified Port. When the transport is 'serialrtu', Port must be specified. This argument is the serial port that the Modbus dual Masters Adaptor hardware is connected to PC, such as 'COM3'. m = ModbusX(Transport,Port,Name,Value) specifies additional options with one or more name-value pair arguments using any of the previous syntaxes. For example, you can specify NumRetries, the number of retries to perform if there is no reply from the server after a timeout. Input Arguments Transport -- Physical transport layer for device communication. character vector | string scalar Physical transport layer for device communication, specified as a character vector or string. Specify transport type as the first argument when you create the modbus object. You must set the transport type as either 'tcpip' or 'serialrtu' to designate the protocol you want to use. For example,m = ModbusX('tcpip','192.168.2.1') DeviceAddress — IP address or host name of Modbus server character vector | string scalar IP address or host name of Modbus server, specified as a character vector or string. If transport is TCP/IP, it is required as the second argument during object creation. Example: m = ModbusX('tcpip','192.168.2.1') Port — Remote port used by Modbus server 502 (default) | double scalar Remote port used by Modbus server, specified as a double. Optional as a third argument during object creation if transport is TCP/IP. The default of 502 is used if none is specified. Example: m = ModbusX('tcpip','192.168.2.1',308) Port — Serial port Modbus server is connected to PC by this Port. character vector | string scalar Serial port "Modbus dual Masters Adaptor hardware USB or Bluetooth" is connected to by this argument, e.g. 'COM1' in windows OS, or "/dev/ttyUSB0" under Linux OS, specified as a character vector or string. If transport is Serial RTU, it is required as the second argument during object creation. Example: m = ModbusX('serialrtu','COM3') Name-Value Arguments Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter. Please, use commas to separate each name and value, and enclose Name in quotes. For example, m = ModbusX('serialrtu','COM3','Timeout',20) You can use Name-Value pairs to set the following arguments:
• | WordOrder
Value is scalar string or char array. It denote the words order when register data type is "uint32/int32/single/uint64/int64/double". Valid value is "big-endian" or "little-endian". Default="big-endian"
• | Timeout
Value is scalar double. Maximum time in seconds to wait for a response from the Modbus server. Maximum time in seconds to wait for a response from the Modbus server, specified as the comma-separated pair consisting of 'Timeout' and a positive value of type double. . The default is 1.1. You can change the value either during object creation or after you create the object. Example: m = ModbusX('serialrtu','COM3','Timeout',20)
• | NumRetries
Value is scalar double. Number of retries to perform if there is no reply or exception reply from the server after a timeout, specified as the comma-separated pair consisting of 'NumRetries' and a positive value of type double.You can change the value either during object creation. The default is 3
• | COM
Value is scalar string or char array. Modbus dual Masters Adaptor hardware is connected to PC by this Port. (This Name-Value is only used for Modbus TCP). When Modbus Server is Modbus TCP, we used this COM to identify whether "Modbus dual Masters Adaptor hardware" connects PC. Our Modbus object only works when "Modbus dual Masters Adaptor hardware" connects PC. Specified as the comma-separated pair consisting of 'COM' and a value of type string or character vector. You can only change the value during object creation. Default='COM1'.
• | BaudRate
Value is scalar double. Default is 19200 bits per second. Valid Value is 4800/9600/19200/28800/38400/43000/57600/115200. Note: This baud rate is not actual Modbus baud rate. It is baud rate for Modbus dual Masters Adaptor Hardware interface with PC. Actual Modbus baud rate is decided by PC ConfigTool.exe software. Modbus TCP needs this Baud rate to identify Modbus dual Masters Adaptor Hardware.
• | Parity
Value is scalar string or char array. Valid choices are 'none' (default), 'even', 'odd'.
• | StopBits
Value is scalar double. Valid choices are 1 (default) and 2. Examples When the transport is TCP/IP, you must specify the IP address or host name of the Modbus server. And your PC must connect our "Modbus dual Masters Adaptor hardware". So if your hardware USB or Bluetooth Serial port is not COM1, you must set up "COM" of name-value pair. . The following statement is usually used in general project: m=ModbusX('tcpip', '192.168.2.1', 'COM', 'COM8', 'BaudRate', 115200, 'Parity', 'none' ); When the transport is 'serialrtu', you must specify a Port argument. This is the serial port that the Modbus dual Masters Adaptor hardware is connected to PC. This baudRate is not actual Modbus baud rate. It is baud rate for Modbus dual Masters Adaptor Hardware interface with PC. Actual Modbus baud rate is decided by PC ConfigTool.exe software. And RTU or ASCii is decided by PC ConfigTool.exe software too. Create the Modbus RTU/ASCii master object m specifying a Port of 'COM3'.. m = ModbusX('serialrtu','COM3', 'BaudRate',19200,'NumRetries',5 ); Properties
• | DeviceAddress — IP address or host name of Modbus server
scalar string or char array. IP address or host name of Modbus server, specified as a character vector or string. If transport is TCP/IP, it is required as the second argument during object creation.
• | Port — Remote port used by Modbus server
scalar double. Remote port used by Modbus server, specified as a double. Optional as a third argument during object creation if transport is TCP/IP. The default of 502 is used if none is specified.
• | Port — Serial port hardware is connected to
scalar string or char array. Serial port "Modbus dual Masters Adaptor hardware USB or Bluetooth" is connected to, e.g. 'COM1', specified as a character vector or string. If transport is Serial RTU, it is required as the second argument during object creation.
• | Timeout — Time out for the Modbus server
scalar double. The default is 1.1. Maximum time in seconds to wait for a response from the Modbus server. You can change the value either during object creation or after you create the object.
• | NumRetries — Number of retries to perform if failure
scalar double. The default is 3. Number of retries to perform if there is no reply or exception reply from the server after a timeout. You can change the value either during object creation or after you create the object.
• | BaudRate — Serial Port Baud Rate
scalar double. Default is 19200 bits per second. Valid Value is 4800/9600/19200/28800/38400/43000/57600/115200. Note: This baud rate is not actual Modbus baud rate. It is baud rate for Modbus dual Masters Adaptor Hardware interface with PC. Actual Modbus baud rate is decided by PC ConfigTool.exe software. Modbus TCP needs this Baud rate to identify Modbus dual Masters Adaptor Hardware. You can change the property only during object creation.
• | Parity — Serial Port Parity
scalar string or char array. Valid choices are 'none' (default), 'even', 'odd'. Note: This Parity is not actual Modbus RTU/ASCii Parity. It is parity for Modbus dual Masters Adaptor Hardware interface with PC. Actual Modbus Parity is decided by PC ConfigTool.exe software. Modbus TCP needs this parity to identify Modbus dual Masters Adaptor Hardware. You can change the property only during object creation.
• | StopBits — Serial Port Stop bits
scalar double. Valid choices are 1 (default) and 2. Note: This StopBits is not actual Modbus RTU/ASCii StopBits. It is StopBits for Modbus dual Masters Adaptor Hardware interface with PC. Actual Modbus StopBits is decided by PC ConfigTool.exe software. Modbus TCP needs this StopBits to identify Modbus dual Masters Adaptor Hardware. You can change the property only during object creation.
• | WordOrder — words order for multiple words' data type
scalar string or char array. It denote the words order when register data type is "uint32/int32/single/uint64/int64/double". Valid value is "big-endian" or "little-endian". Default="big-endian". You can change it in the run-time by assignment Object Functions (Or Methods)
read | read operation on the connected Modbus server
readUserDefinedInputRegs | read input regs operation by specified FC on the connected Modbus server
readUserDefinedInputs | read discrete regs operation by specified FC on the connected Modbus server
write | write operation to the connected Modbus server.
writeUserDefinedHoldingRegs | write holding regs operation by specified FC to the connected Modbus server.
writeUserDefinedCoils | write coil regs operation by specified FC to the connected Modbus server.
writeRead | write then read operation on the connected Modbus server in a single Modbus transaction
maskWrite | Modify the contents of a holding register using a AND mask OR mask parameters
Events None All methods details read Perform a read operation on the connected Modbus server. Since R2019b Syntax [moddata,ErrCode] = read(obj,target,address) [moddata,ErrCode] = read(obj,target,address,count) [moddata,ErrCode] = read(obj,target,address,count,serverId) [moddata,ErrCode] = read(obj,target,address,count,'precision') [moddata,ErrCode] = read(obj,target,address,count,serverId,'precision') Description This function will perform a read operation from one of four target addressable areas: Coils, Inputs, Holding Registers, or Input Registers. Each of the four areas corresponds to a unique Modbus function code, which may or may not be supported by the connected Modbus server. Input Arguments
• | obj — ModbusX object. This argument is mandatory.
• | target — Specifies the area to read. The valid choices are 'coils', 'inputs', 'inputregs' and 'holdingregs'. This argument is mandatory.
• | address — The starting address to read from. This is 1-based address without 4x/3x... prefix. This argument is mandatory.
• | count — The number of values to read. Optional, default is 1. Count is a scalar when doing reads of the same data type. Count is a vector of integers for reading multiple contiguous registers containing different data types. The number of values for count must match the number of values for precision.
• | serverId — The address of the server to send this command to. Optional, default is 1. Valid values are 1-247.
• | precision — Specifies the data format of the register being read from on the Modbus server. Valid values are 'uint16', 'int16', 'uint32', 'int32', 'uint64', 'int64', 'single', and 'double'. Optional, default is 'uint16'
'single' and 'double' conversions conform to the IEEE 754 floating point standard. For signed integers a two's complement conversion is performed. Note that 'precision' does not refer to the return type (always 'double'), it only specifies how to interpret the register data. Precision is a string or char array when doing reads of the same data type. For reading multiple contiguous registers containing different data types, precision must be a cell array of strings or character vectors, or a string array of precisions. The number of precision values must match the number of count values. Only for tagets: inputregs and holdingregs. Output Arguments
• | moddata — Register Values to read.
Row vector for reading result in double number type. It will be [ ] if failed
• | ErrCode — Error Code for reading.
scalar double. The reason of failure in reading, 0 denotes success, 1 denotes ILLEGAL FUNCTION, 2 denotes ILLEGAL DATA ADDRESS, 3 denotes ILLEGAL DATA VALUE , 4 denotes SLAVE DEVICE FAILURE, 6 denotes SLAVE DEVICE BUSY, 16 denotes timeout, 17 denotes frame format error, 18 denotes CRC error. Examples If you are running our "Modbus dual Masters Adaptor hardware" for the first time, please run ConfigTool.exe in Windows OS. Screenshot is shown below: We must use USB serial port to do configure (You cannot use Bluetooth serial port to do configure because Bluetooth needs to be configured too). In above figure, UART1 is one port actual Modbus RTU/ASCii Server is connected to. So UART1 settings are actual Modbus settings. UART2 is USB Serial port which is connected to our PC. So if you use USB serial port to access Modbus RTU/ASCii Server, please use these settings in MATLAB object construction function (ModbusX object). UART3 is Bluetooth Serial port which is connected to our PC. So if you use Bluetooth serial port to access Modbus RTU/ASCii Server, please use these settings in MATLAB object construction function (ModbusX object). Firstly, we set up a ModbusX object (Modbus RTU/ASCii Master) with COM5. All other properties are used default values, it means that Baud Rate=19200, Parity='none', StopBits=1, Timeout=1.1, NumRetries=3, and WordOrder='big-endian' m=ModbusX('serialrtu', 'COM5',); % Read 3 coil values starting at address 5 from Slave node's Server ID =1 address = 5; [moddata,Error] = read(m,'coils',address,3,1); % Read 2 holding registers whose data format is unsigned 16 bits integer and 4 holding registers % whose data format is double, in one read, at address 10 and Server ID=2. address = 10; precision = {'uint16', 'double'}; count = [2, 4]; [moddata, Error] = read(m, 'holdingregs', address, count,2, precision); readUserDefinedInputRegs Perform a input regs read operation by specified FC on the connected Modbus server. Since R2019b Syntax [moddata,ErrCode] = readUserDefinedInputRegs(obj,FC,address) [moddata,ErrCode] = readUserDefinedInputRegs(obj,FC,address,count) [moddata,ErrCode] = readUserDefinedInputRegs(obj,FC,address,count,serverId) [moddata,ErrCode] = readUserDefinedInputRegs(obj,FC,address,count,'precision') [moddata,ErrCode] = readUserDefinedInputRegs(obj,FC,address,count,serverId,'precision') Description As we know, Standard read input registers function code is 4. However, Some server supports non-standard function code (not 4) for reading input registers. This function is designed for this purpose. This function will perform a input registers read operation by user defined Modbus function code, which may or may not be supported by the connected Modbus server. Input Arguments
• | obj — ModbusX object. This argument is mandatory.
• | FC — Specifies the Function code, scalar double, 1 to 255. This argument is mandatory.
• | address — The starting address to read from. This is 1-based address without 4x/3x... prefix. This argument is mandatory.
• | count — The number of values to read. Optional, default is 1. Count is a scalar when doing reads of the same data type. Count is a vector of integers for reading multiple contiguous registers containing different data types. The number of values for count must match the number of values for precision.
• | serverId — The address of the server to send this command to. Optional, default is 1. Valid values are 1-247.
• | precision — Specifies the data format of the register being read from on the Modbus server. Valid values are 'uint16', 'int16', 'uint32', 'int32', 'uint64', 'int64', 'single', and 'double'. Optional, default is 'uint16'
'single' and 'double' conversions conform to the IEEE 754 floating point standard. For signed integers a two's complement conversion is performed. Note that 'precision' does not refer to the return type (always 'double'), it only specifies how to interpret the register data. Precision is a string or char array when doing reads of the same data type. For reading multiple contiguous registers containing different data types, precision must be a cell array of strings or character vectors, or a string array of precisions. The number of precision values must match the number of count values. Output Arguments
• | moddata — Register Values to read.
Row vector for reading result in double number type. It will be [ ] if failed
• | ErrCode — Error Code for reading.
scalar double. The reason of failure in reading, 0 denotes success, 1 denotes ILLEGAL FUNCTION, 2 denotes ILLEGAL DATA ADDRESS, 3 denotes ILLEGAL DATA VALUE , 4 denotes SLAVE DEVICE FAILURE, 6 denotes SLAVE DEVICE BUSY, 16 denotes timeout, 17 denotes frame format error, 18 denotes CRC error. Examples Firstly, we set up a ModbusX object (Modbus RTU/ASCii Master) with COM5. All other properties are used default values, it means that Baud Rate=19200, Parity='none', StopBits=1, Timeout=1.1, NumRetries=3, and WordOrder='big-endian' m=ModbusX('serialrtu', 'COM5',); % Read 2 input registers whose data format is unsigned 16 bits integer and 4 holding registers % whose data format is double, in one read, at address 10 and Server ID=3 But FC =14 which is not standard 4. address = 10; precision = {'uint16', 'double'}; count = [2, 4]; [moddata, Error] = readUserDefinedInputRegs(m, 14, address, count,3, precision); readUserDefinedInputs Perform a discrete regs read operation by specified FC on the connected Modbus server. Since R2019b Syntax [moddata,ErrCode] = readUserDefinedInputs(obj,FC,address) [moddata,ErrCode] = readUserDefinedInputs(obj,FC,address,count) [moddata,ErrCode] = readUserDefinedInputs(obj,FC,address,count,serverId) Description As we know, Standard read discrete registers function code is 2. However, Some server supports non-standard function code (not 2) for reading discrete registers. This function is designed for this purpose. This function will perform a discrete registers read operation by user defined Modbus function code, which may or may not be supported by the connected Modbus server. Input Arguments
• | obj — ModbusX object. This argument is mandatory.
• | FC — Specifies the Function code, scalar double, 1 to 255. This argument is mandatory.
• | address — The starting address to read from. This is 1-based address without prefix. This argument is mandatory.
• | count — The number of values to read. Optional, default is 1. Count is a scalar,which denotes numbers of logical inputs.
• | serverId — The address of the server to send this command to. Optional, default is 1. Valid values are 1-247.
Output Arguments
• | moddata — Register Values to read.
Row vector for reading result in logical number type. It will be [ ] if failed
• | ErrCode — Error Code for reading.
scalar double. The reason of failure in reading, 0 denotes success, 1 denotes ILLEGAL FUNCTION, 2 denotes ILLEGAL DATA ADDRESS, 3 denotes ILLEGAL DATA VALUE , 4 denotes SLAVE DEVICE FAILURE, 6 denotes SLAVE DEVICE BUSY, 16 denotes timeout, 17 denotes frame format error, 18 denotes CRC error. Examples Firstly, we set up a ModbusX object (Modbus TCP Master) with remote TCP address='192.168.1.32'. And Serial Port our hardware is connected to is 'COM5'. All other properties are used default values, it means that Port=502, Baud Rate=19200, Parity='none', StopBits=1, Timeout=1.1, NumRetries=3, and WordOrder='big-endian' m=ModbusX('tcpip', '192.168.1.32, 'COM', 'COM5'); % Read 3 coil values starting at address 5 from Slave node's Server ID =1 (default) , but FC=17 address = 5; [moddata,Error] = readUserDefinedInputs(m, 17, address,3); write Perform a write operation to the connected Modbus server. Since R2019b Syntax ErrCode = write(obj,target,address,values) ErrCode = write(obj,target,address,values,serverId) ErrCode = write(obj,target,address,values,ForceSingleWrite) ErrCode = write(obj,target,address,values,'precision') ErrCode = write(obj,target,address,values,serverId,'precision') ErrCode = write(obj,target,address,values,serverId,ForceSingleWrite) ErrCode = write(obj,target,address,values,serverId,'precision',ForceSingleWrite) Description This function will perform a write operation to one of two writable target addressable areas: Coils or Holding Registers. Each of the two areas can accept a write request to a single address, or a contiguous address range. Each possibility (single coil, multiple coils, single register, multiple registers) corresponds to a unique Modbus function code which may or may not be supported by the connected Modbus server. Input Arguments
• | obj — ModbusX object. This argument is mandatory.
• | target — Specifies the area to write. The valid choices are 'coils' and 'holdingregs'. This argument is mandatory.
• | address — The starting address to write to. This is 1-based address without 4x/0x... prefix. This argument is mandatory.
• | values — Array of values to write. For target 'coils' valid values are logical false and true. For target 'holdingregs' valid values must be in the range of the specified 'precision'. This argument is mandatory.
• | serverId — The address of the server to send this command to. Valid values are 0-247, with 0 being the broadcast address. Optional, default is 1.
• | precision — Specifies the data format of the register being written to on the Modbus server device. Valid values are 'uint16', 'int16', 'uint32', 'int32', 'uint64','int64', 'single', and 'double'. Optional, default is ‘uint16’.
The values passed in to be written will be converted to register values based on the specified precision. 'single' and 'double' conversions conform to the IEEE 754 floating point standard. For signed integers a 2's complement conversion is performed.
• | ForceSingleWrite — Force single register write. Logical Scalar. true means that we will use FC=6 to replace FC=16 for target 'holdingregs', and FC=5 to replace FC=15 for target 'coils'. Otherwise, false means that we will use FC=16 to replace FC=6 for target 'holdingregs', and FC=15 to replace FC=5 for target 'coils'. Optional, default is false.
Output Arguments
• | ErrCode — Error Code.
scalar double. The reason of failure in writing, 0 denotes success, 1 denotes ILLEGAL FUNCTION, 2 denotes ILLEGAL DATA ADDRESS, 3 denotes ILLEGAL DATA VALUE , 4 denotes SLAVE DEVICE FAILURE, 6 denotes SLAVE DEVICE BUSY, 16 denotes timeout, 17 denotes frame format error, 18 denotes CRC error. Examples Firstly, we set up a ModbusX object (Modbus TCP Master) with remote TCP address='192.168.1.32'. And Serial Port our hardware is connected to is 'COM5'. All other properties are used default values, it means that Port=502, Baud Rate=19200, Parity='none', StopBits=1, Timeout=1.1, NumRetries=3, and WordOrder='big-endian' m=ModbusX('tcpip', '192.168.1.32, 'COM', 'COM5'); % set the server ID=1, the holding registers at address 22 to the value 2000 in multiple writings (FC=16) ErrorCode= write(m,'holdingregs',22,2000,1); % set the server ID=1, the holding registers at address 23 to the value 2000 in single writing (FC=6) ErrorCode= write(m,'holdingregs',23,2000,1, true); writeUserDefinedHoldingRegs Perform a holding registers write operation by specified FC to the connected Modbus server. Since R2019b Syntax ErrCode = writeUserDefinedHoldingRegs(obj,FC,address,values) ErrCode = writeUserDefinedHoldingRegs(obj,FC,address,values,serverId) ErrCode = writeUserDefinedHoldingRegs(obj,FC,address,values,'precision') ErrCode = writeUserDefinedHoldingRegs(obj,FC,address,values,serverId,'precision') Description As we know, Standard write holding registers function code is 16 or 6. However, Some server supports non-standard function code (not 16 , not 6) for writing holding registers. This function is designed for this purpose. This function will perform a holding registers write operation by user defined Modbus function code, which may or may not be supported by the connected Modbus server. Input Arguments
• | obj — ModbusX object. This argument is mandatory.
• | FC — Specifies the Function code, scalar double, 1 to 255. This argument is mandatory.
• | address — The starting address to write to. This is 1-based address without 4x prefix. This argument is mandatory.
• | values — Array of values to write. The valid values must be in the range of the specified 'precision'. This argument is mandatory.
• | serverId — The address of the server to send this command to. Valid values are 0-247, with 0 being the broadcast address. Optional, default is 1.
• | precision — Specifies the data format of the register being written to on the Modbus server device. Valid values are 'uint16', 'int16', 'uint32', 'int32', 'uint64','int64', 'single', and 'double'. Optional, default is ‘uint16’.
The values passed in to be written will be converted to register values based on the specified precision. 'single' and 'double' conversions conform to the IEEE 754 floating point standard. For signed integers a 2's complement conversion is performed. Output Arguments
• | ErrCode — Error Code.
scalar double. The reason of failure in writing, 0 denotes success, 1 denotes ILLEGAL FUNCTION, 2 denotes ILLEGAL DATA ADDRESS, 3 denotes ILLEGAL DATA VALUE , 4 denotes SLAVE DEVICE FAILURE, 6 denotes SLAVE DEVICE BUSY, 16 denotes timeout, 17 denotes frame format error, 18 denotes CRC error. Examples Firstly, we set up a ModbusX object (Modbus TCP Master) with remote TCP address='192.168.1.32'. And Serial Port our hardware is connected to is 'COM5'. All other properties are used default values, it means that Port=502, Baud Rate=19200, Parity='none', StopBits=1, Timeout=1.1, NumRetries=3, and WordOrder='big-endian' m=ModbusX('tcpip', '192.168.1.32, 'COM', 'COM5'); % set the server ID=2, the holding registers at address 22 to the value 2000 in FC=14 ErrorCode= writeUserDefinedHoldingRegs(m,14,22,2000,2); writeUserDefinedCoils Perform a coil registers write operation by specified FC to the connected Modbus server. Since R2019b Syntax ErrCode = writeUserDefinedCoils(obj,FC,address,values) ErrCode = writeUserDefinedCoils(obj,FC,address,values,serverId) Description As we know, Standard write coil registers function code is 15 or 5. However, Some server supports non-standard function code (not 15 , not 5) for writing coil registers. This function is designed for this purpose. This function will perform a coil registers write operation by user defined Modbus function code, which may or may not be supported by the connected Modbus server. Input Arguments
• | obj — ModbusX object. This argument is mandatory.
• | FC — Specifies the Function code, scalar double, 1 to 255. This argument is mandatory.
• | address — The starting address to write to. This is 1-based address without prefix. This argument is mandatory.
• | values — Array of values to write. The valid values must be logical true or false. This argument is mandatory.
• | serverId — The address of the server to send this command to. Valid values are 0-247, with 0 being the broadcast address. Optional, default is 1.
Output Arguments
• | ErrCode — Error Code.
scalar double. The reason of failure in writing, 0 denotes success, 1 denotes ILLEGAL FUNCTION, 2 denotes ILLEGAL DATA ADDRESS, 3 denotes ILLEGAL DATA VALUE , 4 denotes SLAVE DEVICE FAILURE, 6 denotes SLAVE DEVICE BUSY, 16 denotes timeout, 17 denotes frame format error, 18 denotes CRC error. Examples Firstly, we set up a ModbusX object (Modbus RTU/ASCii Master) with COM5. All other properties are used default values, it means that Baud Rate=19200, Parity='none', StopBits=1, Timeout=1.1, NumRetries=3, and WordOrder='big-endian' m=ModbusX('serialrtu', 'COM5',); % set the server ID=8, the coil registers at address 22 to the value true, address 23 to false in FC=13 ErrorCode= writeUserDefinedCoils(m,13,22,[true false ],8); writeRead Perform a write then read operation on the connected Modbus server in a single Modbus transaction. Since R2019b Syntax [moddata,ErrCode] = writeRead(obj,writeAddress,writeData,readAddress,readCount) [moddata,ErrCode] = writeRead(obj,writeAddress,writeData,readAddress,... readCount,serverId) [moddata,ErrCode] = writeRead(obj,writeAddress,writeData,'writePrecision',... readAddress,readCount,'readPrecision') [moddata,ErrCode] = writeRead(obj,writeAddress,writeData,'writePrecision',... readAddress,readCount,'readPrecision',serverId) Description This function is used to perform a combination of one write operation and one read operation on groups of holding registers in a single Modbus transaction. The write operation is always performed before the read. The range of addresses to read must be contiguous, and the range of addresses to write must be contiguous, but each are specified independently and may or may not overlap. Input Arguments
• | obj — ModbusX object. This argument is mandatory.
• | writeAddress —The starting address of the registers to write (1-based without prefix). This argument is mandatory.
• | writeData — Array of values to write where the first value in the array is written to writeAddress. This argument is mandatory.
• | writePrecision — Specifies the data format of the register being written to on the Modbus server. Valid values are 'uint16', 'int16', 'uint32', 'int32', 'uint64', 'int64', 'single', and 'double'. Optional, default is 'uint16'
• | readAddress —The starting address of the registers to read (1-based without prefix). This argument is mandatory.
• | readCount — The number of registers to read. Optional, default is 1.
• | serverId — The address of the server to send this command to. Optional, default is 1. Valid values are 1-247.
• | readPrecision — Specifies the data format of the register being read from on the Modbus server. Valid values are 'uint16', 'int16', 'uint32', 'int32', 'uint64', 'int64', 'single', and 'double'. Optional, default is 'uint16'
'single' and 'double' conversions conform to the IEEE 754 floating point standard. For signed integers a two's complement conversion is performed. Note that 'precision' does not refer to the return type (always 'double'), it only specifies how to interpret the register data. Output Arguments
• | moddata — Register Values to read.
Row vector for reading result in double number type. It will be [ ] if failed
• | ErrCode — Error Code for writing/reading.
scalar double. The reason of failure in writing/reading, 0 denotes success, 1 denotes ILLEGAL FUNCTION, 2 denotes ILLEGAL DATA ADDRESS, 3 denotes ILLEGAL DATA VALUE , 4 denotes SLAVE DEVICE FAILURE, 6 denotes SLAVE DEVICE BUSY, 16 denotes timeout, 17 denotes frame format error, 18 denotes CRC error. maskWrite Modify the contents of a holding register using a AND mask OR mask parameters Since R2019b Syntax ErrCode = maskWrite(obj, address, andMask, orMask) ErrCode = maskWrite(obj, address, andMask, orMask, serverId) Description This function is used to set or clear individual bits in a specific holding register; a read/modify/write operation. This is done by using a combination of an AND mask, an OR mask, and the register's current contents. The function’s algorithm is: Result = (register value AND andMask) OR (orMask AND (NOT andMask)) Input Arguments
• | obj — ModbusX object. This argument is mandatory.
• | address —The starting address of the registers to perform mask write on (1-based without prefix). This argument is mandatory.
• | andMask — AND value to use in mask write operation described above. Valid range is 0-65535.. This argument is mandatory.
• | orMask — OR value to use in mask write operation described above. Valid range is 0-65535.. This argument is mandatory.
• | serverId — The address of the server to send this command to. Optional, default is 1. Valid values are 0-247. with 0 being the broadcast address. Optional, default is 1.
Output Arguments
• | ErrCode — Error Code for failure in mask-writing
scalar double. The reason of failure in mask-writing, 0 denotes success, 1 denotes ILLEGAL FUNCTION, 2 denotes ILLEGAL DATA ADDRESS, 3 denotes ILLEGAL DATA VALUE , 4 denotes SLAVE DEVICE FAILURE, 6 denotes SLAVE DEVICE BUSY, 16 denotes timeout, 17 denotes frame format error, 18 denotes CRC error.