modbusClose (Function)

This function will close a MODBUS connection, previously opened by the modbusOpen or modbusOpenX functions.

Input:

net_id : INT

The ID of the MODBUS connection.

Returns: INT

Declaration:

FUNCTION modbusClose;
VAR_INPUT
  net_id : INT;
END_VAR;

Example:

INCLUDE rtcu.inc
 
VAR_INPUT
  switch : BOOL R_EDGE;
END_VAR;
 
VAR
  mb_net : INT;
  mb_id : INT := 0; // open as master
END_VAR;
 
PROGRAM ModbusExample;
 
  mb_net := modbusOpenX(mode := 1, unit_id := mb_id, port := 2, baud := 57600, parity := 0);
 
BEGIN
  IF switch THEN
    // Close MODBUS net
    modbusClose(net_id := mb_net);
 
    // Open new MODBUS net
    IF mb_id = 0 THEN
        mb_id := 1; // open as slave
    ELSE
        mb_id := 0; // open as master
    END_IF;
     mb_net := modbusOpenX(mode := 1, unit_id := mb_id, port := 2, baud := 57600, parity := 0);
  END_IF;
END;
END_PROGRAM;