DeviceAR (FB)

FUNCTION_BLOCK DeviceAR

A Profinet Device application uses this function block for controlling all phases of the connection establishment.

In a Profinet context, this connection is also called Application Relation (AR). The AR maintains a list of configured modules, parameters, and cyclic and acylic communication channels.

One instance of this function block is used for one instance of an AR.

The connection establishment phase consist of these steps:

- Controller sends a Connect-req to the device. This request contains a list of submodules that the controller intends to control (and to exchange cyclic data).

- The Device checks the list of expected vs. the real submodules. In case of a mismatch the stack adds a Module Diff Block which contains all mismatching modules to the Connect-res.

- The Controller sends paramterization data for each configured submodule. The Profinet Device application can receive the parameter data with CommFB.RCVREC function block.

- The Controller sends a PrmEnd-req. for indicating that the paramterization phase is finished.

- The Device application applies the received parameterization data to its internal logic and the hardware.

- The Device application sends the ApplicationReady-req to th controller for indicating that it is ready for data-exchange.

The use of this fucntion block is optional.

But note that once it is enabled/registered for a Profinet Device, the application is responsible for confirming all AR related events within a certain time (typically 20 sec.).

Otherwise the controller will abort the connection with some error code like ‘AR CMI timeout’.

Update Diagnosis

PROGRAM PLC_PRG
VAR
    ar : ProfinetCommon.DeviceAR;   // FB for controlling the AR establishment
    i : DINT;
    checkExp : ProfinetCommon.CheckExpSubmodule;
    moduleDiffCounter : DINT;
    prmDelay : TON;         // some delay for parameterizing the device (example)
    output : DINT;          // a counter variable
END_VAR


ar(xEnable := TRUE, DeviceID := pnDevice.DeviceID);
IF(ar.xAborted) THEN            // connection has been aborted
    ar(xConfirmConnect := FALSE, xConfirmPrmEnd := FALSE, xApplReady := FALSE);     //reset commands
    moduleDiffCounter := 0;     // reset counter
    prmDelay(IN := FALSE);      // reset timer

ELSIF(ar.xData) THEN                // connection estblishment phase sucessful, AR in data exchange
    output := output + 1;

ELSIF(ar.xConnect) THEN                 // received Connect-req., the AR establishment started
    IF(NOT ar.xConfirmConnect) THEN     // not yet confirmed ?
        // check submodule config the controller expects:
        checkExp(xEnable := TRUE, AR_ID := ar.AR_ID);
        FOR i := 0 TO checkExp.ExpectedSubmoduleCount - 1 DO
            checkExp(Index := i);
            IF(checkExp.xModuleDiff) THEN       //some module mismatch, see details
                moduleDiffCounter := moduleDiffCounter + 1;     // count mismatching modules
            END_IF
        END_FOR
        ar(xConfirmConnect := TRUE);        // confirm Connect-req. from controller
    END_IF

    IF(ar.xPrmEnd) THEN                     // received PrmEnd-req. from controller
        ar(xConfirmPrmEnd := TRUE);         // confirm PrmEnd-req.
        prmDelay(IN := TRUE, PT := T#2S);   // start prm-delay timer
    END_IF

    prmDelay();
    IF(prmDelay.Q) THEN             // timer expired
        ar(xApplReady := TRUE);     // Send Application-Ready to Controller --> AR will get into 'Data' state
    END_IF
END_IF

InOut:

Scope	Name	Type	Initial	Comment
Input	xEnable	BOOL		Enable function
	DeviceID	BYTE		ID of the Profinet Device in the local Profinet Device application.
	xConfirmConnect	BOOL		Send Connect-cnf to controller
	xConfirmPrmEnd	BOOL		Send PrmEnd confirmation to controller
	xApplReady	BOOL		Send Application-Ready to controller
Output	xBusy	BOOL		DeviceAR is operating and will receive connection related request and events.
	xError	BOOL		DeviceAR does not operate due to internal error.
	AR_ID	DWORD	CommFB.Constants.INVALID_ID	ID of this AR endpoint.
	AR_Status	DeviceAR_State		Status of this AR endpoint.
	xConnect	BOOL		Received Connect-Req. from Controller.
	xPrmEnd	BOOL		Received PrmEnd-Ind from Controller: All data-records / parameters have been transmitted.
	xData	BOOL		AR is in Data-Exchange
	xAborted	BOOL		AR has been Aborted. (Abort reason see PNIOStatus)
	PNIOStatus	UDINT		Profinet specific protocol status/error code.
	ARInfo	AR_Info		Some information on the current AR