go modbus 
Fault-tolerant, fail-fast implementation of Modbus protocol in Go.
Supported functions
Bit access:
- Read Discrete Inputs
- Read Coils
- Write Single Coil
- Write Multiple Coils
16-bit access:
- Read Input Registers
- Read Holding Registers
- Write Single Register
- Write Multiple Registers
- Read/Write Multiple Registers
- Mask Write Register
- Read FIFO Queue
Supported formats
- TCP
- Serial (RTU, ASCII)
Usage
Basic usage:
// Modbus TCP
client := modbus.TCPClient("localhost:502")
// Read input register 9
results, err := client.ReadInputRegisters(8, 1)
// Modbus RTU/ASCII
// Default configuration is 19200, 8, 1, even
client = modbus.RTUClient("/dev/ttyS0")
results, err = client.ReadCoils(2, 1)Advanced usage:
// Modbus TCP
handler := modbus.NewTCPClientHandler("localhost:502")
handler.Timeout = 10 * time.Second
handler.SlaveId = 0xFF
handler.Logger = log.New(os.Stdout, "test: ", log.LstdFlags)
// Connect manually so that multiple requests are handled in one connection session
err := handler.Connect()
defer handler.Close()
client := modbus.NewClient(handler)
results, err := client.ReadDiscreteInputs(15, 2)
results, err = client.WriteMultipleRegisters(1, 2, []byte{0, 3, 0, 4})
results, err = client.WriteMultipleCoils(5, 10, []byte{4, 3})// Modbus RTU/ASCII
handler := modbus.NewRTUClientHandler("/dev/ttyUSB0")
handler.BaudRate = 115200
handler.DataBits = 8
handler.Parity = "N"
handler.StopBits = 1
handler.SlaveId = 1
handler.Timeout = 5 * time.Second
err := handler.Connect()
defer handler.Close()
client := modbus.NewClient(handler)
results, err := client.ReadDiscreteInputs(15, 2)