serGetStatus (Function)

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Query the status of a serial port.

Input:

port : SINT (0..127) (default 0)

Selects which serial port to query.

Returns: INT

1	- The serial port is open and ready for use.
0	- This function is not supported.
-1	- The serial port is not present.
-2	- The serial port is not open.
-3	- The serial port is open, but the device is not present.

Declaration:

FUNCTION serGetStatus : INT;
VAR_INPUT
port : SINT := 0;
END_VAR;

Example:

INCLUDE rtcu.inc

PROGRAM example;

VAR

status : INT;

old : INT := 999;

END_VAR;

// Enable USB serial port

usbHostEnable(port := 1, enable := ON);

BEGIN

// Get the status of the USB serial port

status := serGetStatus(port := 10);

IF status <> old THEN

CASE status OF

1: DebugMsg(message := "Serial port: Open and ready for use!");

0: DebugMsg(message := "serGetStatus is not supported.");

-1: DebugMsg(message := "Serial port: Not present.");

-2: DebugMsg(message := "Serial port: Not open.");

-3: DebugMsg(message := "Serial port: Device is removed!");

END_CASE;

END_IF;

old := status;

END;

END_PROGRAM;