FB_ALY_TimeBasedTeachPath_1Ch

Time Based Teach Path 1Ch periodically writes the input data to a file according to the configured number of teach operations. This means that the values are not written sequentially for each period, but the values of a new period are compared with the existing values. The period can be defined by the input values Start Period and Stop Period (boolean signals are required). According to the teach mode, each value is overwritten or retained, so that the result is a taught input signal that can later be used as a reference signal for the Time Based Envelope 1Ch algorithm, for example.

Syntax

Definition:

FUNCTION_BLOCK FB_TimeBasedTeachPath_1Ch
VAR_OUTPUT
    ipResultMessage: Tc3_EventLogger.I_TcMessage;
    bError: BOOL;
    bNewResult: BOOL;
    bConfigured: BOOL;
    bBusy: BOOL;
    bTeaching: BOOL;
    eState: E_TeachState;
    nWrittenValues: ULINT;
    nValuesInFile: ULINT;
    nCurrentTeachCycles: ULINT;
END_VAR

Outputs

Methods

State diagram

Due to the asynchronous file access in real time applications this function block needs a state machine to prepare and finish file access.

At startup the function block is in Idle state. To write the incoming data to a file it has to be switched to state Teach. Therefore the method SwitchState_Teach() has to be called once to set the function block to the PendingTeach state. After that the method UpdateState() has to be called until the function block is in state Teach. In this state one or multiple teach cycles can be proceeded. If the function block should not teach additional cycles it can be set to Idle state again. To initiate the state switch the method SwitchState_Idle() has to be called. After that the method UpdateState() has to be called until the function block is in state Idle.

State diagram for the teach procedure of the data:

Sample

VAR
    fbTimeBasedTeach : FB_ALY_TimeBasedTeachPath_1Ch;
    eTeachMode : E_ALY_TeachMode := E_ALY_TeachMode.Mean;
    nSegmentSize : UDINT := 200;
    tTimeout : TIME := T#5S;
    nSetNumTeaches : UDINT := 10;
    bInvolveExistingFile : BOOL := TRUE;
    sFilePath : STRING := 'C:\TwinCAT\3.1\Boot\TimeBasedTeach.tas';
    bNegateStartPeriod : BOOL := FALSE;
    bNegateStopPeriod : BOOL := FALSE;
    bConfigure : BOOL := TRUE;
    eState : E_ALY_TeachState := E_ALY_TeachState.Idle;    
    bTeach : BOOL;
    fInput : LREAL;
    bStartPeriod : BOOL;
    bStopPeriod : BOOL;
END_VAR

// Configure algorithm
IF bConfigure THEN
    bConfigure := FALSE;

    fbTimeBasedTeach.Configure(eTeachMode, nSegmentSize, tTimeout, nSetNumTeaches, bInvolveExistingFile, sFilePath, bNegateStartPeriod, bNegateStopPeriod);
END_IF

// Call algorithm
eState := fbTimeBasedTeach.eState;
CASE eState OF
E_ALY_TeachState.Idle:
    IF bTeach THEN
        fbTimeBasedTeach.SwitchState_Teach();
        fbTimeBasedTeach.UpdateState();
    END_IF    
E_ALY_TeachState.Teach:
    fbTimeBasedTeach.SetChannelValue(fInput);
    fbTimeBasedTeach.Call(bStartPeriod := bStartPeriod, bStopPeriod := bStopPeriod);
    
    IF NOT bTeach THEN
        fbTimeBasedTeach.SwitchState_Idle();    
        fbTimeBasedTeach.UpdateState();
    END_IF    
E_ALY_TeachState.Pending,
E_ALY_TeachState.PendingIdle,
E_ALY_TeachState.PendingTeach:
    fbTimeBasedTeach.UpdateState();
    eState := fbTimeBasedTeach.eState;
END_CASE

Requirements