Real-Time SPC™  Support

Variable specifications

Learn more about Real-Time SPC
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 values are text and numeric.
  • Character maximum 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 values are text and numeric.
  • Character maximum 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.
ID Name Required Configurations Optional Configurations
Product ID Product Names
  • Products
  • Process Measures
  • Output Measures
  • Defects
  • Defectives
 none
Process ID Process Names
  • Processes
  • Process Measures
  • Output Measures
  • Defects
  • Defectives
 none
Station ID Station Names Stations
  • Process Measures
  • Output Measures
  • Defects
  • Defectives
not available Measure Names
  • Descriptors
  • Process Measures
  • Output Measures
  • Defects
  • Defectives
 none

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.

Variable Configurations Requirements
Measure Name Required in Descriptors configurations
  • Accepted values are text and numeric.
  • Character maximum is 150 characters. Data rows that exceed the ID character limit cannot be imported.
Note

IDs are case-sensitive, and duplicate IDs are not allowed. Only measure names are required. Measure IDs are not accepted.

Type Optional in Descriptors configurations 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 Optional in Descriptors configurations Use one of the following values to represent descriptor scopes.
  • Product
  • Global
If not specified, the default of Product is used.
Use Optional in Descriptors configurations 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 Optional in Descriptors configurations 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 Optional in Descriptors configurations 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 Optional in Descriptors configurations When list values are provided, the Select from a List collection method is used.

When values are not provided, the Enter Values collection method with the defaults of Share within and Retain user-supplied values is used.

Control chart types

The available control chart type depends on the type of measure. The following table indicates the available control charts and the defaults for the process measures, output measures, defects, and defectives.
Available Configurations Chart Requirements
For continuous control charts, Type is optional in Process Measures and Output Measures configurations.

Valid type options are: imr, imrrs, xbarr, xbars, imrrs, ewma

If not specified, or if an invalid entry, the following defaults are used.
  • default = imr, when subgroup size = 1
  • default = xbarr, when subgroup size ≥ 2.
For defect control charts, Type is optional in Defects configurations.

Valid type options are: c, u, uprime

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

For defectives control charts, Type is optional in 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 > 0.
  • Mean defects must be numeric values > 0.
  • Proportion defective values must be numeric values 0 ≤ Proportion ≤ 1.
  • Sigma Z values must be numeric values > 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.

Available Configurations Chart Requirements
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.

For defects control charts, Limits is optional in Defects configurations.

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

For defectives control charts, Limits is optional in Defectives configurations.

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

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, Defects, and 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

Specification and action limits

Specification Limits
Specifying default specification limits is optional in Process Measures, Output Measures, Defects, and Defectives configurations.

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, Defects, and 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

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, Defects, and Defectives configurations.

Numeric values only
  • LSL ≤ Target
  • USL ≥ 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 0 ≤ Weight ≤ 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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