COM port functions
COM Port Read
FUNCTION F_COMPORTREAD
VAR_INPUT
hCom :INT;
cbRxBuffer :UINT;
pRxBuffer :UDINT;
Legend
hCom: is connected with the iHandle of FB_COMPORTOPEN
cbRxBuffer: maximum length of data that can be read.
pRxBuffer: pointer to data to be written with the COM buffer content
|
Return value |
Meaning |
|---|---|
|
> 0 |
Number of bytes that is to be copied from the COM buffer into the PLC. |
|
0x8000 |
Memory overflow |
COM Port Write
FUNCTION F_COMPORTWRITE
VAR_INPUT
hCom :INT;
cbTxBuffer :UINT;
pTxBuffer :UDINT;
Legend
hCom: is connected with the iHandle of FB_COMPORTOPEN
cbTxBuffer: Number of data bytes that were copied into the COM buffer.
pTxBuffer: Pointer to the data from which the COM buffer is to be filled.
|
Return value |
Meaning |
|---|---|
|
> 0 |
Number of bytes that is to be copied into the COM buffer from the PLC |
|
0x8000 |
Memory overflow |