package modbusx
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import (
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"encoding/binary"
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"sync/atomic"
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)
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func Read(ipAddr string, address uint16, quantity uint16) (data []byte, err error) {
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address--
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cli := getModbusConnection(ipAddr)
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data, err = cli.ReadHoldingRegisters(address, quantity)
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dealErr(err, ipAddr)
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if err != nil {
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cli = getModbusConnection(ipAddr)
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data, err = cli.ReadHoldingRegisters(address, quantity)
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dealErr(err, ipAddr)
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}
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return
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}
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func Write(ipAddr string, address uint16, value int) (err error) {
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var bytesVal []byte
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if value <= 1<<16 {
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uint16ToBytes(uint16(value))
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} else {
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bytesVal = intToBytes(value)
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}
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cli := getModbusConnection(ipAddr)
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_, err = cli.WriteMultipleRegisters(address, uint16(len(bytesVal)), bytesVal)
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dealErr(err, ipAddr)
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return err
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}
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func uint16ToBytes(value uint16) []byte {
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// 创建一个长度为2的字节切片
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bytes := make([]byte, 2)
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// 将 uint16 的值写入字节切片，可以选择使用大端或小端字节序
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bytes[0] = byte(value >> 8) // 获取高8位
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bytes[1] = byte(value) // 获取低8位
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return bytes
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}
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func intToBytes(value int) []byte {
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// 创建一个长度为4的字节切片，用于存储 int 值
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bytes := make([]byte, 4)
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// 使用 binary 包将 int 值转换为字节切片
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binary.BigEndian.PutUint32(bytes, uint32(value))
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return bytes
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}
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func dealErr(err error, ipAddr string) {
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if err != nil {
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unsetModbusConnection(ipAddr) //失败则删除缓存的连接
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FailureRemainingOpportunitiesDecr() //减少失败剩余机会
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} else {
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FailureRemainingOpportunitiesReset() //重置失败剩余机会
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}
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}
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var connectionStatus atomic.Bool
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var failureRemainingOpportunities atomic.Int64
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const (
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defaultFailureRemainingOpportunities = 20
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)
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func IsConnect() bool {
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return connectionStatus.Load()
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}
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func FailureRemainingOpportunitiesDecr() {
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newValue := failureRemainingOpportunities.Add(-1)
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if newValue <= 0 {
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connectionStatus.Store(false)
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}
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return
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}
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func FailureRemainingOpportunitiesReset() {
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if failureRemainingOpportunities.Load() < defaultFailureRemainingOpportunities {
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failureRemainingOpportunities.Store(defaultFailureRemainingOpportunities)
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}
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if connectionStatus.Load() == false {
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connectionStatus.Store(true)
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}
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return
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}
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