The" chInit()" function will initialize a CHANNEL variable with the specified maximum number of messages.
The chInit() function must be called before any other operation on the channel can be performed.
Input:
msgmax : INT
Maximum number of messages that can be present in the channel before the chWrite() function will block.
Returns: CHANNEL
The initialized channel.
Declaration:
FUNCTION chInit : CHANNEL;
VAR_INPUT
msgmax : INT;
END_VAR;
Example:
INCLUDE rtcu.inc
VAR_INPUT
al_1 : BOOL R_EDGE;
al_2 : BOOL R_EDGE;
END_VAR;
VAR
chalarm : CHANNEL;
END_VAR;
// SMS thread
THREAD_BLOCK smsalarm;
VAR
alarmno : SINT;
END_VAR;
WHILE TRUE DO
chRead(ch:=chalarm,msg:=ADDR(alarmno),lenmax:=SIZEOF(alarmno));
gsmSendSMS(phonenumber := "22448899", message := strFormat(format:="Alarm. Door \1", v1:=alarmno));
END_WHILE;
END_THREAD_BLOCK;
PROGRAM test;
VAR
smshandler : smsalarm;
alarm : sint;
END_VAR;
//main thread
chalarm := chInit(msgMax:=10);
smshandler();
gsmPower(power := TRUE);
BEGIN
IF al_1 THEN
alarm:=1;
chWrite(ch:=chalarm,msg:=ADDR(alarm),len:=SIZEOF(alarm));
END_IF;
IF al_2 THEN
alarm:=2;
chWrite(ch:=chalarm,msg:=ADDR(alarm),len:=SIZEOF(alarm));
END_IF;
END;
END_PROGRAM;
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