client

package
v0.0.0-...-91c7ab2 Latest Latest
Warning

This package is not in the latest version of its module.

Go to latest
Published: Mar 27, 2025 License: Apache-2.0 Imports: 10 Imported by: 0

Documentation

Overview

Package modbus provides a client for MODBUS TCP and RTU/ASCII.

Index

Constants

View Source
const (
	// Bit access
	FuncCodeReadDiscreteInputs = 2
	FuncCodeReadCoils          = 1
	FuncCodeWriteSingleCoil    = 5
	FuncCodeWriteMultipleCoils = 15

	// 16-bit access
	FuncCodeReadInputRegisters         = 4
	FuncCodeReadHoldingRegisters       = 3
	FuncCodeWriteSingleRegister        = 6
	FuncCodeWriteMultipleRegisters     = 16
	FuncCodeReadWriteMultipleRegisters = 23
	FuncCodeMaskWriteRegister          = 22
	FuncCodeReadFIFOQueue              = 24
)
View Source
const (
	ExceptionCodeIllegalFunction                    = 1
	ExceptionCodeIllegalDataAddress                 = 2
	ExceptionCodeIllegalDataValue                   = 3
	ExceptionCodeServerDeviceFailure                = 4
	ExceptionCodeAcknowledge                        = 5
	ExceptionCodeServerDeviceBusy                   = 6
	ExceptionCodeMemoryParityError                  = 8
	ExceptionCodeGatewayPathUnavailable             = 10
	ExceptionCodeGatewayTargetDeviceFailedToRespond = 11
)
View Source
const (
	FuncCodeCsg = 0x66
)

Variables

This section is empty.

Functions

This section is empty.

Types

type ASCIIClientHandler

type ASCIIClientHandler struct {
	// contains filtered or unexported fields
}

ASCIIClientHandler implements Packager and Transporter interface.

func NewASCIIClientHandler

func NewASCIIClientHandler(address string) *ASCIIClientHandler

NewASCIIClientHandler allocates and initializes a ASCIIClientHandler.

func (*ASCIIClientHandler) Decode

func (mb *ASCIIClientHandler) Decode(adu []byte) (pdu *ProtocolDataUnit, err error)

Decode extracts PDU from ASCII frame and verify LRC.

func (*ASCIIClientHandler) Encode

func (mb *ASCIIClientHandler) Encode(pdu *ProtocolDataUnit) (adu []byte, err error)

Encode encodes PDU in a ASCII frame:

Start           : 1 char
Address         : 2 chars
Function        : 2 chars
Data            : 0 up to 2x252 chars
LRC             : 2 chars
End             : 2 chars

func (*ASCIIClientHandler) Send

func (mb *ASCIIClientHandler) Send(aduRequest []byte) (aduResponse []byte, err error)

func (*ASCIIClientHandler) SetSlaveID

func (handler *ASCIIClientHandler) SetSlaveID(slaveID uint8)

func (*ASCIIClientHandler) Verify

func (mb *ASCIIClientHandler) Verify(aduRequest []byte, aduResponse []byte) (err error)

Verify verifies response length, frame boundary and slave id.

type Client

type Client interface {

	// ReadCoils reads from 1 to 2000 contiguous status of coils in a
	// remote device and returns coil status.
	ReadCoils(address, quantity uint16) (results []byte, err error)
	// ReadDiscreteInputs reads from 1 to 2000 contiguous status of
	// discrete inputs in a remote device and returns input status.
	ReadDiscreteInputs(address, quantity uint16) (results []byte, err error)
	// WriteSingleCoil write a single output to either ON or OFF in a
	// remote device and returns output value.
	WriteSingleCoil(address, value uint16) (results []byte, err error)
	// WriteMultipleCoils forces each coil in a sequence of coils to either
	// ON or OFF in a remote device and returns quantity of outputs.
	WriteMultipleCoils(address, quantity uint16, value []byte) (results []byte, err error)

	// ReadInputRegisters reads from 1 to 125 contiguous input registers in
	// a remote device and returns input registers.
	ReadInputRegisters(address, quantity uint16) (results []byte, err error)
	// ReadHoldingRegisters reads the contents of a contiguous block of
	// holding registers in a remote device and returns register value.
	ReadHoldingRegisters(address, quantity uint16) (results []byte, err error)
	// WriteSingleRegister writes a single holding register in a remote
	// device and returns register value.
	WriteSingleRegister(address, value uint16) (results []byte, err error)
	// WriteMultipleRegisters writes a block of contiguous registers
	// (1 to 123 registers) in a remote device and returns quantity of
	// registers.
	WriteMultipleRegisters(address, quantity uint16, value []byte) (results []byte, err error)
	// ReadWriteMultipleRegisters performs a combination of one read
	// operation and one write operation. It returns read registers value.
	ReadWriteMultipleRegisters(readAddress, readQuantity, writeAddress, writeQuantity uint16, value []byte) (results []byte, err error)
	// MaskWriteRegister modify the contents of a specified holding
	// register using a combination of an AND mask, an OR mask, and the
	// register's current contents. The function returns
	// AND-mask and OR-mask.
	MaskWriteRegister(address, andMask, orMask uint16) (results []byte, err error)
	//ReadFIFOQueue reads the contents of a First-In-First-Out (FIFO) queue
	// of register in a remote device and returns FIFO value register.
	ReadFIFOQueue(address uint16) (results []byte, err error)

	//Send  send with custom data block
	Send(funcCode byte, dataBlock []byte) (results []byte, err error)
}

func ASCIIClient

func ASCIIClient(address string) Client

ASCIIClient creates ASCII client with default handler and given connect string.

func NewClient

func NewClient(handler ClientHandler) Client

NewClient creates a new modbus client with given backend handler.

func NewClient2

func NewClient2(packager Packager, transporter Transporter) Client

NewClient2 creates a new modbus client with given backend packager and transporter.

func RTUClient

func RTUClient(address string) Client

RTUClient creates RTU client with default handler and given connect string.

type ClientHandler

type ClientHandler interface {
	Packager
	Transporter
}

ClientHandler is the interface that groups the Packager and Transporter methods.

type ModbusError

type ModbusError struct {
	FunctionCode  byte
	ExceptionCode byte
}

ModbusError implements error interface.

func (*ModbusError) Error

func (e *ModbusError) Error() string

Error converts known modbus exception code to error message.

type Packager

type Packager interface {
	Encode(pdu *ProtocolDataUnit) (adu []byte, err error)
	Decode(adu []byte) (pdu *ProtocolDataUnit, err error)
	Verify(aduRequest []byte, aduResponse []byte) (err error)
	SetSlaveID(slaveID uint8)
}

Packager specifies the communication layer.

type ProtocolDataUnit

type ProtocolDataUnit struct {
	FunctionCode byte
	Data         []byte
}

ProtocolDataUnit (PDU) is independent of underlying communication layers.

type RTUClientHandler

type RTUClientHandler struct {
	// contains filtered or unexported fields
}

RTUClientHandler implements Packager and Transporter interface.

func NewRTUClientHandler

func NewRTUClientHandler(address string) *RTUClientHandler

NewRTUClientHandler allocates and initializes a RTUClientHandler.

func (*RTUClientHandler) Decode

func (mb *RTUClientHandler) Decode(adu []byte) (pdu *ProtocolDataUnit, err error)

Decode extracts PDU from RTU frame and verify CRC.

func (*RTUClientHandler) Encode

func (mb *RTUClientHandler) Encode(pdu *ProtocolDataUnit) (adu []byte, err error)

Encode encodes PDU in a RTU frame:

Slave Address   : 1 byte
Function        : 1 byte
Data            : 0 up to 252 bytes
CRC             : 2 byte

func (*RTUClientHandler) Send

func (mb *RTUClientHandler) Send(aduRequest []byte) (aduResponse []byte, err error)

func (*RTUClientHandler) SetSlaveID

func (mb *RTUClientHandler) SetSlaveID(slaveID uint8)

func (*RTUClientHandler) Verify

func (mb *RTUClientHandler) Verify(aduRequest []byte, aduResponse []byte) (err error)

Verify verifies response length and slave id.

type Transporter

type Transporter interface {
	Send(aduRequest []byte) (aduResponse []byte, err error)
	Connect() (err error)
	Close() (err error)
}

Transporter specifies the transport layer.

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL