Quality (SPC) Charts Overview

You can leverage Proficy Portal's SPC (statistical process control) charts as an end-user configurable web-based solution that allows you to improve the quality and consistency of products and processes by providing visibility into manufacturing and process information.

Quality charts are used to detect uncontrolled variation in processes. Typically, a sampling of data from the process in question is interpreted by the chart. The chart plots data points based on the samples and uses statistical process analysis tools such as center line, upper control limit, lower control limit, sigma limit, alarm rules, and so forth to show whether the process is in statistical control.

NOTE: You will have access to Quality charts only if your company has purchased the Enterprise edition of Proficy Portal.


Most of the Quality charts are classified into two groups: variable charts and attribute charts. Variable charts are used to analyze data that is derived from measurements such as time, length, temperature, and so forth. The following variable charts are available with the Proficy Portal Quality module:

XBar charts

Moving XBar charts

Range charts

Moving Range charts

Sigma charts

Individual charts

XBar-R charts

Histogram charts

XBar-S charts

Attribute charts are used to analyze attributes data. Attributes data either counts the number of defects per item or group of items (nonconformities), or it counts the number of defective items (nonconforming). The following attribute charts are available with the Proficy Portal Quality module:

Pareto charts

P charts

NP charts

C charts

U charts

One chart – the Correlation chart – does not fit into either the variable or attributes categories. Correlation charts are used to compare any two data elements.


Proficy Portal Quality users can maximize efficiency by connecting Quality charts directly to a number of data sources. For example, Proficy Portal can connect with:

See Also

Quality (SPC) Charts Features

XBar chart

Range chart

Sigma chart

XBar-R chart

XBar-S chart

Moving XBar chart

Moving Range chart

Individual chart

Histogram chart

Pareto chart

P chart

Np chart

C chart

U chart

Correlation chart

Exporting Data from SPC Charts

Alarm Indication

Bad Data Handling


VisualSPC Data Sources