Configuring the SPC block

Double click on the SPC block and configure the fields below.

Selected KPI field

Description: Select the field on which to calculate SPC statistics.

Constraints: Only double and integer fields may be selected.

Limits

Lower Specification Limit

Description: The lower bound of the specification limit for your process.

Constraints: This can be either a double value or a field on the parameter port.

Upper Specification Limit

Description: The upper bound of the specification limit for your process.

Constraints: This can either be a double value or a field on the parameter port.

Subgroups

Sampling period (seconds)

Description: The period at which samples are taken for SPC calculations.

Constraints: Any double number greater than 0.

Samples per subgroup

Description: The number of samples that make up a subgroup.

Constraints: Only integers greater than 1 are allowed.

Subgroup period (seconds)

Description: A read-only edit box showing the total period of the time window for a single subgroup.

Window size

Subgroups per window

Description: The number of subgroups in the calculation window for SPC statistics. There may initially be fewer subgroups in the calculation window, but as the window fills up, this number denotes the maximum number of subgroups in the window that are used to calculate statistics.

Constraints: Only integer numbers greater than 1 are allowed.

Calculation window

Description: This indicates the maximum amount of time that a calculation window for SPC statistics can cover. This window fills up gradually upon execution and eventually saturates at this maximum size as more data comes in.

Subgroup statistics

Calculations performed on SPC subgroups are listed here.

Calculate using pooled standard deviation

Description: Enable this check box for subgroup statistics to be calculated during execution. Disable the check box to manually enter the means and standard deviations for various subgroup statistics. When manually entering these values, output values for UCL, LCL, mean, and sigma will be calculated for the subgroup statistics from your entered values instead of deriving them from your input data to the block.