FB_ALY_ScalerFitting

The Scaler Fitting module can be used to determine the parameters for feature scaling and save them in a file. These parameters can then be used in the Scaler module.

The parameters required for scaling are determined depending on the operation mode.

Normalization:

Standardization:

Syntax

Definition:

FUNCTION_BLOCK FB_ScalerFitting
VAR_OUTPUT
    ipResultMessage: Tc3_EventLogger.I_TcMessage;
    bError: BOOL;
    bNewResult: BOOL;
    bConfigured: BOOL;
    fScalingParam1: LREAL;
    fScalingParam2: LREAL;
    bBusy: BOOL;
    eState: E_TeachState;
END_VAR

Outputs

Name	Type	Description
ipResultMessage	I_TcMessage	Contains more detailed information on the current return value. For this special interface pointer, it is ensured internally that it is always valid/assigned.
bError	BOOL	The output is `TRUE` if an error occurs.
bNewResult	BOOL	When a new result has been calculated, the output is `TRUE.`
bConfigured	BOOL	Displays `TRUE` when the function block is successfully configured.
fScalingParam1	LREAL	Outputs the first scaling parameter depending on the scaling mode: Normalization: Smallest value of the input channel. Standardization: Mean value of the input channel.
fScalingParam1	LREAL	Outputs the second scaling parameter depending on the scaling mode: Normalization: Largest value of the input channel. Standardization: Standard deviation of the input channel.
bBusy	BOOL	`TRUE` if the FB is active due to a file access.
eState	E_ALY_TeachState	Current state of the function block. See state diagram.

Methods

Name	Definition location	Description
Call()	Local	Method for calculating the outputs for a specific configuration.
Configure()	Local	General configuration of the algorithm with its parameterized conditions.
GetBusyState()	Local	This method returns the Busy state of the function block.
Reset()	Local	Resets all internal states or the calculations performed so far.
SetChannelValue()	Local	Method for passing values to the algorithm.
SwitchState_Idle()	Local	Method for setting the function block to Idle state when the teach-in process is complete.
SwitchState_Teach()	Local	Method for putting the function block into teach-in mode.
UpdateState()	Local	State update after a state change has been initiated with one of the SwitchState methods. Is called up until the target state is reached.

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
    fbScalerFitting : FB_ALY_ScalerFitting_1Ch;
    tTimeout : TIME := T#5S;
    eScalingMode : E_ALY_ScalingMode := E_ALY_ScalingMode.Normalization;
    sFilePath : STRING := '%TC_BOOTPRJPATH%\Scaler.json';
    bConfigure : BOOL := TRUE;
    eState : E_ALY_TeachState := E_ALY_TeachState.Idle;
    bTeach : BOOL;
    fInput : LREAL;
    bFit : BOOL;
END_VAR

// Configure algorithm
IF bConfigure THEN
    bConfigure := FALSE;
    fbScalerFitting.Configure(eScalingMode, tTimeout, sFilePath);
END_IF

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

Requirements

Development environment	Target platform	Plc libraries to include
TwinCAT v3.1.4024.0	PC or CX (x64, x86)	Tc3_Analytics

Further Information