FB_ALY_RMS_1Ch

RMS 1Ch calculates the root mean square over the input values according to the formula

The number of samples N that are included in the calculation can be configured by specifying a time interval. A cascaded output can be configured to realize a long-term RMS in a resource-saving way and to pick up intermediate results. The time interval of the configured cascade must correspond to an integer multiple of the time interval of the previous cascade.

Syntax

Definition:

FUNCTION_BLOCK FB_ALY_RMS_1Ch
VAR_OUTPUT
    ipResultMessage: Tc3_EventLogger.I_TcMessage;
    bError: BOOL;
    bNewResult: BOOL;
    bConfigured: BOOL;
END_VAR

Outputs

Name	Type	Description
ipResultMessage	I_TcMessage	Contains more detailed information on the current return value. This special interface pointer is internally secured so that it is always valid/assigned.
bError	BOOL	This 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.

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.
SetCascades()	Local	Method for configuring the cascades. The call is made after the call to the Configure method.
Reset()	Local	Resets all internal states or the calculations performed so far.
SetChannelValue()	Local	Method for passing values to the algorithm.

Sample

VAR
    fbRMS_1Ch : FB_ALY_RMS_1Ch;
    fbSystemTime : FB_ALY_GetSystemTime;
    nNumCascades : UDINT := 5;
    fSampleRate : UDINT := 1000;
    eStartupBehaviour : E_ALY_CascadeStartupBehaviour := E_ALY_CascadeStartupBehaviour.UsePreviousCascadeValue;
    aCascadesConfigArray : ARRAY[1..5] OF LTIME := [LTIME#20MS, LTIME#1S, LTIME#1M, LTIME#1H, LTIME#1D];
    bConfigure : BOOL := TRUE;
    fInput : LREAL;
    aRMS : ARRAY[1..5] OF LREAL;
    aNewResult : ARRAY[1..5] OF BOOL;
END_VAR

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

    fbRMS_1Ch.Configure(nNumCascades, fSampleRate, eStartupBehaviour);
    fbRMS_1Ch.SetCascades(ADR(aCascadesConfigArray), SIZEOF(aCascadesConfigArray));    
END_IF

// Get current system time
fbSystemTime.Call();

// Call algorithm
fbRMS_1Ch.SetChannelValue(fInput);
fbRMS_1Ch.Call(fbSystemTime.tSystemTime, ADR(aRMS), SIZEOF(aRMS), ADR(aNewResult), SIZEOF(aNewResult));

Requirements

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

Further Information