function modbusWriteSingleRegister()

Write value from to single register using modbus protocol. The call is asynchronous: the code execution proceeds immediately and when the response arrives, callback function is called.

nil modbusWriteSingleRegister(table config)

Parameters

table config{deviceAddress, callback, address, value, port, timeout}

• string deviceAddress IP address of device
• function{response} callback this function is called when response arrives
• string address number of the register
• number value the value to be written
• optional number port numer of port (default 502)
• optional number timeout maximum seconds to wait for response (default 30)

Callback Parameters

table response{result, errInfo, address, value}

• number result error code of the response (0 is success)
• string errInfo error description (if result>0)
• number address number of the input register

Return value

nil

Usage

-- Switch state of all outputs on NETIO with IP 10.0.0.105 and port 505
local function modbusWriteCallback(data)
  log(string.format("addr %d, result %d", data.address, data.result))
end

for i = 101,104 do
  modbusWriteSingleRegister{deviceAddress='10.0.0.105', port=505, timeout=6, address=i, value=4, callback=modbusWriteCallback}
end

Requirements

Netio FirmWare 3.3.0+