SerialHardware UCMVirtual UCM

The serial library provides a unified interface for serial communication, supporting both RS-232 and RS-485.

The serial library is available for:

• ENP-RS232, using RS-232 hardware port,
• ENP-RS485, using 1 RS-485 hardware port,
• ENP-RS-CAN-USB M2, using RS-232 or RS-485 hardware ports,
• Virtual UCM on Welotec Arrakis Mk3/Mk4, using 2 RS-232/RS-485 hardware ports.

serial.new

Configure First

RS-232/RS-485 hardware ports must be configured before use.

-- @param connection_uri string Connection URI
-- @return serial object|nil, string|nil
function serial.new(connection_uri)
end

Creates a new serial client. The connection URI should specify the desired serial device.

Use port schema to access hardware ports.

On failure, it returns nil and an error message string.

client Object

client:flush

-- @return string|nil
function client:flush()
end

Clears the input buffer of the serial connection.

On success, the function returns nil. On failure, it returns an error message string.

client:read

-- @param count number Number of bytes to read
-- @param timeout number Timeout (in milliseconds) to complete the read
-- @return string|nil, string|nil
function client:read(count, timeout)
end

Reads exactly count bytes from the serial connection or fails after timeout milliseconds.

On success, the function returns read data as a string. On failure, it returns nil and an error message string.

Example

-- Read 1024 bytes or timeout after 100 milliseconds
local data, err = client:read(1024, 100)
if err ~= nil then
  enapter.log("Error reading serial data: " .. err, "error")
end

client:write

-- @param data string Data to send over the serial connection
-- @return string|nil
function client:write(data)
end

Writes the data to the serial connection.

On success, the function returns nil. On failure, it returns an error message string.

Example

local err = client:write("hello")
if err ~= nil then
  enapter.log("Error writing serial data: " .. err, "error")
end

client:transaction

-- @param action function Function performing serial operations
-- @return any|nil, string|nil
function client:transaction(action)
end

Executes a transaction with exclusive access to the serial port. The action function can contain multiple operations.

On success, the function returns the result of action. On failure, it returns nil and an error message string.

Example

local data, err = client:transaction(function()
  client:flush()
  client:write("hello")
  system.delay(100)
  client:write("world")
  system.delay(1000)
  return client:read(1024)
end)