FC_ComIecWrite

FC_ComIecWrite - General Information

Overview

Type:	Function
Available as of:	SystemInterface_1.32.6.0
Versions:	Current version

Task

Write character to the logical device.

Description

This function writes characters to the logical device i_stComIecId. It writes i_diSize characters. When calling, transfer the address of a variable to i_diBuffer. The characters to be written are taken from this variable. The function transfers the data to the serial driver and returns. The driver performs the write operation autonomously.

NOTE: Note for "RS 485 2-wire" that the hardware has to switch (TriState) between transmitting and receiving. Therefore, a waiting period of at least 5 ms is necessary between sending ( FC_ComIecWrite()) and receiving ( FC_ComIecRead()).

Interface

Input	Data type	Description
i_stComIecId	ST_LogicalAddress	Device selection
i_diBuffer	DINT	Buffer address
i_diSize	DINT	Number of characters that have to be written

Return Value

Data type	Description
DINT	0...: Number of bytes written -1: i_stComIecId invalid -2: other error detected. Contact your Schneider Electric contact person.

Examples

Task

Write a program for testing the COM2 serial interface. Characters are sent via the serial interface COM2. The transmission and reception lines (pin 2 -> 5 pin 3 -> 4) are interconnected in a COM4 plug. The sent characters are received again by the COM2.

Declaration

PROGRAM ComIecLoopBackDemo
VAR
   lState: DINT := 1;
   bStart: BOOL := FALSE;
   lResultOpen: DINT;
   lResultWrite: DINT;
   lResultReadCount: DINT;
   lResultRead: DINT;
   lReadCount: DINT := 0;
   pszRBuffer: STRING := 'PacDriveM';
   pszWBuffer: STRING := 'ELAU the Future of Packaging';
   lWSize: DINT := 28;
END_VAR

Program

CASE lState OF

1:
IF bStart THEN

lResultOpen := FC_ComIecOpen(_ComIec); lState := 2; END_IF

2:
   lResultWrite := FC_ComIecWrite(_ComIec, ADR(pszWBuf fer), lWSize);
   pszRBuffer := 'PacDriveM';
   lState:= 3;

3:
   lResultReadCount := FC_ComIecGetReadCount(_ComIec);
   IF lResultReadCount = lWSize THEN
      lResultRead := FC_ComIecRead(_ComIec, ADR(pszRBuffer), lWSize);
      lReadCount := lReadCount + lResultReadCount;
      IF bStart THEN
         lState := 2;
      ELSE
         FC_ComIecClose(_ComIec);
         lState := 1;
      END_IF
   END_IF
END_CASE