495 lines
15 KiB
Go
495 lines
15 KiB
Go
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// Copyright 2014 Quoc-Viet Nguyen. All rights reserved.
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// This software may be modified and distributed under the terms
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// of the BSD license. See the LICENSE file for details.
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package modbus
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import (
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"encoding/binary"
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"fmt"
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)
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// ClientHandler is the interface that groups the Packager and Transporter methods.
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type ClientHandler interface {
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Packager
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Transporter
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}
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type client struct {
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packager Packager
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transporter Transporter
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}
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// NewClient creates a new modbus client with given backend handler.
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func NewClient(handler ClientHandler) Client {
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return &client{packager: handler, transporter: handler}
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}
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// NewClient2 creates a new modbus client with given backend packager and transporter.
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func NewClient2(packager Packager, transporter Transporter) Client {
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return &client{packager: packager, transporter: transporter}
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}
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// Request:
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// Function code : 1 byte (0x01)
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// Starting address : 2 bytes
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// Quantity of coils : 2 bytes
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// Response:
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// Function code : 1 byte (0x01)
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// Byte count : 1 byte
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// Coil status : N* bytes (=N or N+1)
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func (mb *client) ReadCoils(address, quantity uint16) (results []byte, err error) {
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if quantity < 1 || quantity > 2000 {
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err = fmt.Errorf("modbus: quantity '%v' must be between '%v' and '%v',", quantity, 1, 2000)
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return
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}
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeReadCoils,
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Data: dataBlock(address, quantity),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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count := int(response.Data[0])
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length := len(response.Data) - 1
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if count != length {
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err = fmt.Errorf("modbus: response data size '%v' does not match count '%v'", length, count)
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return
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}
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results = response.Data[1:]
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return
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}
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// Request:
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// Function code : 1 byte (0x02)
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// Starting address : 2 bytes
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// Quantity of inputs : 2 bytes
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// Response:
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// Function code : 1 byte (0x02)
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// Byte count : 1 byte
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// Input status : N* bytes (=N or N+1)
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func (mb *client) ReadDiscreteInputs(address, quantity uint16) (results []byte, err error) {
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if quantity < 1 || quantity > 2000 {
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err = fmt.Errorf("modbus: quantity '%v' must be between '%v' and '%v',", quantity, 1, 2000)
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return
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}
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeReadDiscreteInputs,
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Data: dataBlock(address, quantity),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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count := int(response.Data[0])
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length := len(response.Data) - 1
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if count != length {
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err = fmt.Errorf("modbus: response data size '%v' does not match count '%v'", length, count)
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return
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}
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results = response.Data[1:]
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return
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}
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// Request:
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// Function code : 1 byte (0x03)
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// Starting address : 2 bytes
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// Quantity of registers : 2 bytes
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// Response:
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// Function code : 1 byte (0x03)
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// Byte count : 1 byte
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// Register value : Nx2 bytes
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func (mb *client) ReadHoldingRegisters(address, quantity uint16) (results []byte, err error) {
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if quantity < 1 || quantity > 125 {
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err = fmt.Errorf("modbus: quantity '%v' must be between '%v' and '%v',", quantity, 1, 125)
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return
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}
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeReadHoldingRegisters,
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Data: dataBlock(address, quantity),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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count := int(response.Data[0])
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length := len(response.Data) - 1
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if count != length {
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err = fmt.Errorf("modbus: response data size '%v' does not match count '%v'", length, count)
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return
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}
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results = response.Data[1:]
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return
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}
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// Request:
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// Function code : 1 byte (0x04)
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// Starting address : 2 bytes
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// Quantity of registers : 2 bytes
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// Response:
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// Function code : 1 byte (0x04)
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// Byte count : 1 byte
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// Input registers : N bytes
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func (mb *client) ReadInputRegisters(address, quantity uint16) (results []byte, err error) {
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if quantity < 1 || quantity > 125 {
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err = fmt.Errorf("modbus: quantity '%v' must be between '%v' and '%v',", quantity, 1, 125)
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return
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}
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeReadInputRegisters,
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Data: dataBlock(address, quantity),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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count := int(response.Data[0])
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length := len(response.Data) - 1
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if count != length {
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err = fmt.Errorf("modbus: response data size '%v' does not match count '%v'", length, count)
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return
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}
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results = response.Data[1:]
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return
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}
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// Request:
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// Function code : 1 byte (0x05)
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// Output address : 2 bytes
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// Output value : 2 bytes
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// Response:
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// Function code : 1 byte (0x05)
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// Output address : 2 bytes
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// Output value : 2 bytes
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func (mb *client) WriteSingleCoil(address, value uint16) (results []byte, err error) {
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// The requested ON/OFF state can only be 0xFF00 and 0x0000
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if value != 0xFF00 && value != 0x0000 {
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err = fmt.Errorf("modbus: state '%v' must be either 0xFF00 (ON) or 0x0000 (OFF)", value)
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return
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}
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeWriteSingleCoil,
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Data: dataBlock(address, value),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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// Fixed response length
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if len(response.Data) != 4 {
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err = fmt.Errorf("modbus: response data size '%v' does not match expected '%v'", len(response.Data), 4)
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return
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}
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respValue := binary.BigEndian.Uint16(response.Data)
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if address != respValue {
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err = fmt.Errorf("modbus: response address '%v' does not match request '%v'", respValue, address)
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return
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}
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results = response.Data[2:]
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respValue = binary.BigEndian.Uint16(results)
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if value != respValue {
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err = fmt.Errorf("modbus: response value '%v' does not match request '%v'", respValue, value)
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return
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}
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return
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}
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// Request:
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// Function code : 1 byte (0x06)
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// Register address : 2 bytes
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// Register value : 2 bytes
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// Response:
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// Function code : 1 byte (0x06)
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// Register address : 2 bytes
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// Register value : 2 bytes
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func (mb *client) WriteSingleRegister(address, value uint16) (results []byte, err error) {
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeWriteSingleRegister,
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Data: dataBlock(address, value),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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// Fixed response length
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if len(response.Data) != 4 {
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err = fmt.Errorf("modbus: response data size '%v' does not match expected '%v'", len(response.Data), 4)
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return
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}
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respValue := binary.BigEndian.Uint16(response.Data)
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if address != respValue {
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err = fmt.Errorf("modbus: response address '%v' does not match request '%v'", respValue, address)
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return
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}
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results = response.Data[2:]
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respValue = binary.BigEndian.Uint16(results)
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if value != respValue {
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err = fmt.Errorf("modbus: response value '%v' does not match request '%v'", respValue, value)
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return
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}
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return
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}
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// Request:
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// Function code : 1 byte (0x0F)
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// Starting address : 2 bytes
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// Quantity of outputs : 2 bytes
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// Byte count : 1 byte
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// Outputs value : N* bytes
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// Response:
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// Function code : 1 byte (0x0F)
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// Starting address : 2 bytes
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// Quantity of outputs : 2 bytes
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func (mb *client) WriteMultipleCoils(address, quantity uint16, value []byte) (results []byte, err error) {
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if quantity < 1 || quantity > 1968 {
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err = fmt.Errorf("modbus: quantity '%v' must be between '%v' and '%v',", quantity, 1, 1968)
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return
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}
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeWriteMultipleCoils,
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Data: dataBlockSuffix(value, address, quantity),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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// Fixed response length
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if len(response.Data) != 4 {
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err = fmt.Errorf("modbus: response data size '%v' does not match expected '%v'", len(response.Data), 4)
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return
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}
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respValue := binary.BigEndian.Uint16(response.Data)
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if address != respValue {
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err = fmt.Errorf("modbus: response address '%v' does not match request '%v'", respValue, address)
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return
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}
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results = response.Data[2:]
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respValue = binary.BigEndian.Uint16(results)
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if quantity != respValue {
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err = fmt.Errorf("modbus: response quantity '%v' does not match request '%v'", respValue, quantity)
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return
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}
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return
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}
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// Request:
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// Function code : 1 byte (0x10)
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// Starting address : 2 bytes
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// Quantity of outputs : 2 bytes
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// Byte count : 1 byte
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// Registers value : N* bytes
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// Response:
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// Function code : 1 byte (0x10)
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// Starting address : 2 bytes
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// Quantity of registers : 2 bytes
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func (mb *client) WriteMultipleRegisters(address, quantity uint16, value []byte) (results []byte, err error) {
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if quantity < 1 || quantity > 123 {
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err = fmt.Errorf("modbus: quantity '%v' must be between '%v' and '%v',", quantity, 1, 123)
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return
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}
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeWriteMultipleRegisters,
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Data: dataBlockSuffix(value, address, quantity),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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// Fixed response length
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if len(response.Data) != 4 {
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err = fmt.Errorf("modbus: response data size '%v' does not match expected '%v'", len(response.Data), 4)
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return
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}
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respValue := binary.BigEndian.Uint16(response.Data)
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if address != respValue {
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err = fmt.Errorf("modbus: response address '%v' does not match request '%v'", respValue, address)
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return
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}
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results = response.Data[2:]
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respValue = binary.BigEndian.Uint16(results)
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if quantity != respValue {
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err = fmt.Errorf("modbus: response quantity '%v' does not match request '%v'", respValue, quantity)
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return
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}
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return
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}
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// Request:
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// Function code : 1 byte (0x16)
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// Reference address : 2 bytes
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// AND-mask : 2 bytes
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// OR-mask : 2 bytes
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// Response:
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// Function code : 1 byte (0x16)
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// Reference address : 2 bytes
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// AND-mask : 2 bytes
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// OR-mask : 2 bytes
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func (mb *client) MaskWriteRegister(address, andMask, orMask uint16) (results []byte, err error) {
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request := ProtocolDataUnit{
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FunctionCode: FuncCodeMaskWriteRegister,
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Data: dataBlock(address, andMask, orMask),
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}
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response, err := mb.send(&request)
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if err != nil {
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return
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}
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// Fixed response length
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if len(response.Data) != 6 {
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err = fmt.Errorf("modbus: response data size '%v' does not match expected '%v'", len(response.Data), 6)
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return
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}
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respValue := binary.BigEndian.Uint16(response.Data)
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if address != respValue {
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err = fmt.Errorf("modbus: response address '%v' does not match request '%v'", respValue, address)
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return
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}
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respValue = binary.BigEndian.Uint16(response.Data[2:])
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if andMask != respValue {
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err = fmt.Errorf("modbus: response AND-mask '%v' does not match request '%v'", respValue, andMask)
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return
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}
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respValue = binary.BigEndian.Uint16(response.Data[4:])
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if orMask != respValue {
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err = fmt.Errorf("modbus: response OR-mask '%v' does not match request '%v'", respValue, orMask)
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return
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}
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results = response.Data[2:]
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return
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}
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// Request:
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// Function code : 1 byte (0x17)
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// Read starting address : 2 bytes
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// Quantity to read : 2 bytes
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// Write starting address: 2 bytes
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// Quantity to write : 2 bytes
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// Write byte count : 1 byte
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// Write registers value : N* bytes
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// Response:
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// Function code : 1 byte (0x17)
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// Byte count : 1 byte
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// Read registers value : Nx2 bytes
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func (mb *client) ReadWriteMultipleRegisters(readAddress, readQuantity, writeAddress, writeQuantity uint16, value []byte) (results []byte, err error) {
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if readQuantity < 1 || readQuantity > 125 {
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|
|
err = fmt.Errorf("modbus: quantity to read '%v' must be between '%v' and '%v',", readQuantity, 1, 125)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
if writeQuantity < 1 || writeQuantity > 121 {
|
||
|
|
err = fmt.Errorf("modbus: quantity to write '%v' must be between '%v' and '%v',", writeQuantity, 1, 121)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
request := ProtocolDataUnit{
|
||
|
|
FunctionCode: FuncCodeReadWriteMultipleRegisters,
|
||
|
|
Data: dataBlockSuffix(value, readAddress, readQuantity, writeAddress, writeQuantity),
|
||
|
|
}
|
||
|
|
response, err := mb.send(&request)
|
||
|
|
if err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
count := int(response.Data[0])
|
||
|
|
if count != (len(response.Data) - 1) {
|
||
|
|
err = fmt.Errorf("modbus: response data size '%v' does not match count '%v'", len(response.Data)-1, count)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
results = response.Data[1:]
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// Request:
|
||
|
|
// Function code : 1 byte (0x18)
|
||
|
|
// FIFO pointer address : 2 bytes
|
||
|
|
// Response:
|
||
|
|
// Function code : 1 byte (0x18)
|
||
|
|
// Byte count : 2 bytes
|
||
|
|
// FIFO count : 2 bytes
|
||
|
|
// FIFO count : 2 bytes (<=31)
|
||
|
|
// FIFO value register : Nx2 bytes
|
||
|
|
func (mb *client) ReadFIFOQueue(address uint16) (results []byte, err error) {
|
||
|
|
request := ProtocolDataUnit{
|
||
|
|
FunctionCode: FuncCodeReadFIFOQueue,
|
||
|
|
Data: dataBlock(address),
|
||
|
|
}
|
||
|
|
response, err := mb.send(&request)
|
||
|
|
if err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
if len(response.Data) < 4 {
|
||
|
|
err = fmt.Errorf("modbus: response data size '%v' is less than expected '%v'", len(response.Data), 4)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
count := int(binary.BigEndian.Uint16(response.Data))
|
||
|
|
if count != (len(response.Data) - 1) {
|
||
|
|
err = fmt.Errorf("modbus: response data size '%v' does not match count '%v'", len(response.Data)-1, count)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
count = int(binary.BigEndian.Uint16(response.Data[2:]))
|
||
|
|
if count > 31 {
|
||
|
|
err = fmt.Errorf("modbus: fifo count '%v' is greater than expected '%v'", count, 31)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
results = response.Data[4:]
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// Helpers
|
||
|
|
|
||
|
|
// send sends request and checks possible exception in the response.
|
||
|
|
func (mb *client) send(request *ProtocolDataUnit) (response *ProtocolDataUnit, err error) {
|
||
|
|
aduRequest, err := mb.packager.Encode(request)
|
||
|
|
if err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
aduResponse, err := mb.transporter.Send(aduRequest)
|
||
|
|
if err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
if err = mb.packager.Verify(aduRequest, aduResponse); err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
response, err = mb.packager.Decode(aduResponse)
|
||
|
|
if err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
// Check correct function code returned (exception)
|
||
|
|
if response.FunctionCode != request.FunctionCode {
|
||
|
|
err = responseError(response)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
if response.Data == nil || len(response.Data) == 0 {
|
||
|
|
// Empty response
|
||
|
|
err = fmt.Errorf("modbus: response data is empty")
|
||
|
|
return
|
||
|
|
}
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// dataBlock creates a sequence of uint16 data.
|
||
|
|
func dataBlock(value ...uint16) []byte {
|
||
|
|
data := make([]byte, 2*len(value))
|
||
|
|
for i, v := range value {
|
||
|
|
binary.BigEndian.PutUint16(data[i*2:], v)
|
||
|
|
}
|
||
|
|
return data
|
||
|
|
}
|
||
|
|
|
||
|
|
// dataBlockSuffix creates a sequence of uint16 data and append the suffix plus its length.
|
||
|
|
func dataBlockSuffix(suffix []byte, value ...uint16) []byte {
|
||
|
|
length := 2 * len(value)
|
||
|
|
data := make([]byte, length+1+len(suffix))
|
||
|
|
for i, v := range value {
|
||
|
|
binary.BigEndian.PutUint16(data[i*2:], v)
|
||
|
|
}
|
||
|
|
data[length] = uint8(len(suffix))
|
||
|
|
copy(data[length+1:], suffix)
|
||
|
|
return data
|
||
|
|
}
|
||
|
|
|
||
|
|
func responseError(response *ProtocolDataUnit) error {
|
||
|
|
mbError := &ModbusError{FunctionCode: response.FunctionCode}
|
||
|
|
if response.Data != nil && len(response.Data) > 0 {
|
||
|
|
mbError.ExceptionCode = response.Data[0]
|
||
|
|
}
|
||
|
|
return mbError
|
||
|
|
}
|