Real-Time SPC™  Support

Variable specifications

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All variable import configurations of your Real-Time SPC subscription must comply with the following specifications.

In This Topic

Names and IDs

Variable names and IDs are required.
Names
  • Accepted value types: text or numeric.
  • Maximum length is 200 characters for names. Names that are too long will be truncated.
  • Names are case-insensitive, and duplicate names are not allowed. If a product name is not provided, the product ID is used as name and ID.
IDs
  • Accepted value types: text or numeric.
  • Maximum length is 150 characters for IDs. Data rows that exceed the ID character limit cannot be imported.
  • IDs are case-sensitive, and duplicate IDs are not allowed.

Descriptor variables

Descriptors are categorical variables that identify individual observations or subgroups. For example, your company may collect supplier lot numbers, shift identifiers, and measuring device identifiers.You can add descriptor markers to control charts for each product process.

Measure names are required in the Descriptors configurations. All other items are optional.
Measure Name
Only measure names are required. Measure IDs are not accepted.
  • Accepted value types: text or numeric.
  • Character maximum is 150 characters. Data rows that exceed the ID character limit cannot be imported.
  • IDs are case-sensitive and duplicate IDs are not allowed.
Type
Use one of the following values to represent descriptor types.
  • None
  • Materials
  • Products
  • Operators
Other text values will be accepted. If not specified, the default of None is used.
Scope
Use one of the following values to represent descriptor scopes.
  • Product
  • Global
If not specified, the default of Product is used.
Use
Use one of the following values to represent whether the descriptor values apply to an entire subgroup or to individual observations.
  • Subgroup
  • Individual observation
If not specified, the default of Subgroup is used.
Share within
Specify the text value that represents the group within which to share the descriptor list values. The value (group) that you specify must match an existing hierarchy group. If not specified, or if an invalid entry, the default of Station is used.
Retain user-supplied values
Specify an integer value that represents how long, in days, to retain a list value. Valid entries are between 0 and 365. If not specified, or if an invalid entry, the default of 7 is used.
List values
  • When list values are provided, the Select from a List collection method is used.
  • When list values are not provided, the Enter Values collection method with the defaults of Share within and Retain user-supplied values is used.
Add Markers
Specify chart markers for up to five subgroup descriptors. Only the first five descriptor markers where Add Markers is Yes will display.

Control chart types

The available control chart type depends on the type of measure.

Continuous control chart types

For continuous control charts, Type is optional in Process Measures and Output Measures configurations.

Valid continuous control chart type options are: imr, imrrs, xbarr, xbars, imrrs, ewma. If not specified, or if an invalid entry, the control chart defaults are used, based on subgroup size.

Defaults:
  • when subgroup size = 1, default chart = imr
  • when subgroup size ≥ 2, default chart = xbarr

Defect control chart types

For defect control charts, Type is optional in Grouped Defects configurations.

Valid type options are: c, u, uprime.

If not specified, or if an invalid entry, the default of c is used.

Defective control chart types

For defectives control charts, Type is optional in Defective Measures and Grouped Defectives configurations.

Valid type options are: np, p, pprime.

If not specified, or if an invalid entry, the default of np is used.

Control chart limits

Specifying the method for control limit calculations is optional. Unless all parameters are specified, control limits are calculated with recent data.
  • Use recent to estimate parameters and calculate control limits with recent data.
  • Use fixed to set control limits with historical parameters.
Historical Parameter Requirements
When specifying historical parameters, use Limits = fixed.
  • Mean values must be numeric.
  • Standard deviation values must be numeric values greater than 0.
  • Mean defects must be numeric values greater than 0.
  • Proportion defective values must be numeric values between or equal to 0 and 1.
  • Sigma Z values must be numeric values greater than 0.
Note

If Limits is set to recent or any parameter is null, specified parameters are ignored. Subgroup size is required and will be set to 1, if missing.

Continuous control chart limits

For continuous control charts, Limits is optional in Process Measures and Output Measures configurations.

Chart types of imr, xbarr, xbars, and ewma require both Mean and Standard Deviation for fixed control limits.

Chart type of imrrs require Mean, Standard Deviation Between Subgroups, and Standard Deviation Within Subgroups for fixed control limits.

Defect control chart limits

For defect control charts, Limits is optional in Grouped Defects configurations.

Chart types of c, u, and uprime require Mean Defects for fixed control limits. Uprime charts also require Sigma Z.

Defective control chart limits

For defectives control charts, Limits is optional in Defective Measures and Grouped Defectives configurations.

Chart types of np, p, and pprime require Proportion Defective for fixed control limits. Pprime charts also require Sigma Z.

Net content limits

Specifying net content limits is optional in Output Measures and Process Measures configurations.

Limit Type = Net Content Limits

The following are optional net content specifications. All values must be numeric values, greater than 0.
  • Label Stated Content (LSC)
  • Lower maximum allowable variation (LMAV)
  • Upper maximum allowable variation (UMAV)
  • Lower T1
  • Lower T2
  • Upper T1
  • Upper T2
  • Lower action limit (LAL)
  • Upper action limit (UAL)
Requirements for LSC:
  • LSC > LMAV
  • LSC > LT1
  • LSC > LT2
  • LSC < UMAV
  • LSC < UT1
  • LSC < UT2
Requirements for T1 and T2:
  • LT2 < LT1
  • UT2 > UT1
Requirements for MAV:
  • LMAV < UMAV
Requirements for action limits:
  • LAL < UAL

If you specify either tolerable error 1 or tolerable error 2, then you must specify both.

Number of subgroups or observations

You can specify the amount of data to use for the initial control limit calculations, when Limits = recent.

Specifying default number of observations/subgroups for control limit calculations is optional in Process Measures, Output Measures, Defective Measures, Grouped Defects, and Grouped Defectives configurations.

Integer values > 0. If not specified, or if an invalid entry, the following defaults are used.
  • default = 100, for continuous measures
  • default = 25, for defect measures
  • default = 25, for defective measures and grouped defectives

Specification and action limits

Specifying specification limits is optional in Process Measures, Output Measures, Defective Measures, Grouped Defects, and Grouped Defectives configurations.

Limit Type = Specification Limits

Specification limits
Numeric values only, USL > LSL.
Note

Defects and Defectives configurations have only upper specifications, not lower specifications.

Action limits
Specifying default action limits is optional in Process Measures and Output Measures configurations.

Numeric values only, UAL > LAL.

Subgroup size

Specifying default subgroup sizes for sampling plans is optional in Process Measures, Output Measures, Defective Measures, Grouped Defects, and Grouped Defectives configurations.

Integer values > 0. If not specified, or if an invalid entry, the following defaults are used.
  • default = 1, for continuous measures
  • default = 50, for defect measures
  • default = 100, for defective measures and grouped defectives

Target

Target values are optional. If you enter a target value, Real-Time SPC calculates Cpm, a capability index that considers how much the data deviate from the target.

Optional in Process Measures, Output Measures, Defective Measures, Grouped Defects, and Grouped Defectives configurations.

Numeric values only
  • LSL must be less than or equal to Target
  • USL must be greater than or equal to Target

Weight

Weight values are optional with EWMA control charts.

Process Measures and Output Measures configurations, when control charts Type is set to ewma.

Weight values must be numeric values between or equal to 0 and 1.

Note

If control charts Type is not set to ewma, weight is ignored. Subgroup size is required and will be set to 1, if missing.

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