Automatic control function programming manual ladder language

PERIPHERAL
Transmission
to peripheral
256-CHARACTER
LINEAR BUFFER
Function
comout()
BUFFER
TO BE SENT
Serial Lines
@ %M.n
Figure 12.1 - Transmission of a buffer
12.4 Reception of a Buffer comin
Syntax
comin(portno, &buffer, nb)
portno: Communication port number (0 to B).
&buffer: Address of the buffer where the characters received are to be stored.
nb: Maximum number of characters to be read.
Reads from the reception buffer of serial line portno.
Operation
The system manages a 236 character circular reception buffer. Function comin() is used to read all or part of the buffer.
The number of characters read is equal to the number of characters requested (nb) or the number of characters present
in the circular buffer, whichever is lower.
If the line was not already set to reception by function comctl(), the first call to comin() causes an immediate switch
to reception.
The call to comin(portno, &buffer, 0) causes a stop and initialises reception.
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