ST_WG_Weighing_Validation

Substructure for the configuration structure ST_WG_Weighing. Set parameters affect the function block outputs bValidMeasurement, bNewResult, tLastResult, fLastWeight and fLastStd.

(*This configure struct helps to find the actual weight during one measuring cycle.
A measuring cycle starts when FB_WG_Weighing.fWeight exceeds fThresholdWeight and ends when it falls below fRelativeWeightLimit*FB_WG_Weighing.fLastWeight or fThresholdWeight (if fRelativeWeightLimit is not set).
The actual weight will be displayed in FB_WG_Weighing.fLastWeight (FB_WG_Weighing.fWeight with smallest FB_WG_Weighing.fStd).

Optional parameters are ignored if they are zero. None of the parameters can be less than zero.*)
TYPE ST_WG_Weighing_Validation :
STRUCT    
    fThresholdWeight       : LREAL    := 50.0;   (* Minimum value for the measured weight. This condition is fulfilled if FB_WG_Weighing.fWeight is greater than or equal to fThresholdWeight. *)
    nValidationSamples     : UDINT    := 10;     (* Number of input values for which the other ST_WG_Weighing_Validation parameter conditions (fThresholdWeight, fMaxStd, fMaxWeightDeviation) must be fulfilled so that FB_WG_Weighing.bValidMeasurement=TRUE (optional, recommended). *)
    fMaxStd                : LREAL    := 5.0;    (* Upper limit for the standard deviation. This condition is fulfilled if FB_WG_Weighing.fStd is less than or equal to fMaxStd (optional, recommended). *)
    fMaxWeightDeviation    : LREAL    := 0.0;     (* Upper limit for the maximum weight deviation. This condition is fulfilled if FB_WG_Weighing.fMax - FB_WG_Weighing.fMin is less than or equal to fMaxWeightDeviation (optional, recommended). *)
    fRelativeWeightLimit   : LREAL    := 0.0;     (* fRelativeWeightLimit (> 0 and < 1) specifies that FB_WG_Weighing.bNewResult and FB_WG_Weighing.tLastResult are updated if FB_WG_Weighing.fWeight falls below the fRelativeWeightLimit * FB_WG_Weighing.fLastWeight limit value (optional). *)
END_STRUCT
END_TYPE

• fThresholdWeight is the minimum value for the measured weight. This condition is met if FB_WG_Weighing.fWeight is greater than or equal to fThresholdWeight.
• nValidationSamples is the number of input values for which the other ST_WG_Weighing_Validation parameter conditions (fThresholdWeight, fMaxStd, fMaxWeightDeviation) must be fulfilled so that FB_WG_Weighing.bValidMeasurement=TRUE (optional, recommended).
• fMaxStd is the upper limit for the standard deviation. This condition is met if FB_WG_Weighing.fStd is less than or equal to fMaxStd (optional, recommended).
• fMaxWeightDeviation is the upper limit for the maximum weight deviation. This condition is met if FB_WG_Weighing.fMax - FB_WG_Weighing.fMin is less than or equal to fMaxWeightDeviation (optional, recommended).
• fRelativeWeightLimit (> 0 and < 1) specifies that FB_WG_Weighing.bNewResult and FB_WG_Weighing.tLastResult are updated if FB_WG_Weighing.fWeight falls below the limit value fRelativeWeightLimit-FB_WG_Weighing.fLastWeight (optional).

If FB_WG_Weighing.fWeight rises above fThresholdWeight, the weight with the lowest FB_WG_Weighing.fStd is searched for until FB_WG_Weighing.fWeight leaves the fThresholdWeight limit again. If fRelativeWeightLimit is set, the measurement ends when FB_WG_Weighing.fWeight falls below fThresholdWeight*fRelativeWeightLimit. The weight determined is displayed for the first time on a rising edge of FB_WG_Weighing.bValidMeasurement in FB_WG_Weighing.fLastWeight and is updated until the measurement is complete. At the end of the measurement, the timestamp is set in FB_WG_Weighing.tLastResult and FB_WG_Weighing.bNewResult is set to TRUE for one cycle. If FB_WG_Weighing.fWeight rises above fThresholdWeight again, FB_WG_Weighing.fLastWeight is set to zero and a new measurement begins.