IsReceiveBufferRead

Valutare se il buffer di ricezione viene letto

Questa istruzione restituisce il valore del flag di lettura del buffer di ricezione su una porta di comunicazione specificata.

Parametri

Ingresso

Port (WORD, INT, UINT)

Specifica le porte di comunicazione (in base al tipo di PLC):

Porta COM p.es. SYS_COM0_PORT
MCU/SCU p.es. 16#xx01 (xx = numero slot) in COM01

Uscita

IsRead (BOOL): Impostato su TRUE se il buffer di ricezione è stato letto.

Argomenti correlati

Porte di comunicazione

Istruzioni di sistema

Finestra ancorabile Istruzioni

Aree di memoria

Tipi di dati

Example

POU header

All input and output variables used for programming this function have been declared in the POU header. The same POU header is used for all programming languages.

	VAR
		iPort: INT:=0;
		bIsReceptionDone: BOOL:=FALSE;
		awDataBuffer: ARRAY [0..2] OF WORD:=[3(0)];
		bIsReceiverBufferRead: BOOL:=FALSE;
		bReadReceiveBuffer: BOOL:=FALSE;
	END_VAR

LD body

BODY
    WORKSPACE
        NETWORK_LIST_TYPE := NWTYPELD ;
        ACTIVE_NETWORK := 0 ;
    END_WORKSPACE
    NET_WORK
        NETWORK_TYPE := NWTYPELD ;
        NETWORK_LABEL :=  ;
        NETWORK_TITLE :=  ;
        NETWORK_HEIGHT := 3 ;
        NETWORK_BODY
B(B_F,IsReceptionDone!,,14,0,23,3,,?DPort?CIsDone);
B(B_VARIN,,iPort,12,1,14,3,);
B(B_VAROUT,,bIsReceptionDone,23,1,25,3,);
L(1,0,1,3);
        END_NETWORK_BODY
    END_NET_WORK
    NET_WORK
        NETWORK_TYPE := NWTYPELD ;
        NETWORK_LABEL :=  ;
        NETWORK_TITLE :=  ;
        NETWORK_HEIGHT := 3 ;
        NETWORK_BODY
B(B_CONTACT,,bIsReceptionDone,5,1,7,3,);
B(B_CONTACT,,bReadReceiveBuffer,14,1,16,3,N);
B(B_COIL,,bReadReceiveBuffer,40,1,42,3,S);
L(1,2,5,2);
L(16,2,40,2);
L(7,2,14,2);
L(1,0,1,3);
        END_NETWORK_BODY
    END_NET_WORK
    NET_WORK
        NETWORK_TYPE := NWTYPELD ;
        NETWORK_LABEL :=  ;
        NETWORK_TITLE :=  ;
        NETWORK_HEIGHT := 4 ;
        NETWORK_BODY
B(B_F,E_ReceiveData!,,14,0,23,4,,?DEN?DPort?AENO?CReceiveData);
B(B_VARIN,,iPort,12,2,14,4,);
B(B_VAROUT,,awDataBuffer,23,2,25,4,);
B(B_CONTACT,,bReadReceiveBuffer,5,1,7,3,);
L(1,2,5,2);
L(7,2,14,2);
L(1,0,1,4);
        END_NETWORK_BODY
    END_NET_WORK
    NET_WORK
        NETWORK_TYPE := NWTYPELD ;
        NETWORK_LABEL :=  ;
        NETWORK_TITLE :=  ;
        NETWORK_HEIGHT := 3 ;
        NETWORK_BODY
B(B_VARIN,,iPort,12,1,14,3,);
B(B_VAROUT,,bIsReceiverBufferRead,30,1,32,3,);
B(B_F,IsReceiveBufferRead!,,14,0,25,3,,?DPort?CIsRead);
L(25,2,30,2);
L(1,0,1,3);
        END_NETWORK_BODY
    END_NET_WORK
    NET_WORK
        NETWORK_TYPE := NWTYPELD ;
        NETWORK_LABEL :=  ;
        NETWORK_TITLE :=  ;
        NETWORK_HEIGHT := 3 ;
        NETWORK_BODY
B(B_CONTACT,,bIsReceiverBufferRead,5,1,7,3,);
B(B_COIL,,bReadReceiveBuffer,40,1,42,3,E);
L(7,2,40,2);
L(1,2,5,2);
L(1,0,1,3);
        END_NETWORK_BODY
    END_NET_WORK
END_BODY

NOTA

IsReceiveBufferRead is only active (=TRUE) directly after the ReceiveData command has been executed.

In the next PLC cycle IsReceiveBufferRead will not be active (=FALSE).

ST body

bIsReceptionDone := IsReceptionDone(Port := iPort);
If (bIsReceptionDone) AND NOT (bReadReceiveBuffer) then
    bReadReceiveBuffer := TRUE;
End_if;

If (bIsReceiverBufferRead) then
    awDataBuffer := ReceiveData(iPort);
End_if;

bIsReceiverBufferRead := IsReceiveBufferRead(Port := iPort);

If (bIsReceptionDone) then
    bReadReceiveBuffer := FALSE;
End_if;