SPC Operation Overview


Suggested readings


SPC uses statistical methods to determine whether processes are within required limits. While CIMPLICITY's normal alarm functions detect when individual Points actually exceed limits, SPC analysis can provide early warning by detecting undesirable systematic variations in your process. This can help you pinpoint process, machine, operator, or material problems so that actions can be taken to diagnose and resolve the problem.

CIMPLICITY performs a series of functions in order to provide you with information through the SPC option.

The following process supports SPC.

SPC Configuration tells the Data Collector how and from where to collect the data.

The Data Collector gathers CIMPLICITY Point, ODBC and manual entry data, performs its required calculations and stores the results in the SPC ODBC data source.

The SPC ActiveX control displays the data from the SPC ODBC data source. It can also send manual entry data back to the Data Collector for processing.

A Quality Characteristic can be configured to generate a CIMPLICITY alarm if it goes out of control based on a number of control tests.  The SPC Data Collector will generate this alarm.

The data is retrieved from ODBC logging, analyzed according to the standard SPC calculations for the chart, and displayed graphically by populating configured charts with the result. This ActiveX control can be used in CimEdit/CimView screens or other applications, like Internet Explorer that supports ActiveX controls.

The SPC variable charts display values between -4 sigma (-4) and +4 sigma (+4). Data outside of this range is not displayed, but it is still used in the chart calculations.

Suggested Readings

This documentation shows you how to use the SPC option available for CIMPLICITY Plant Edition. To acquire additional information about SPC, please consult one of the many SPC publications that are currently available.

Suggested publications are:

Easy as SPC, Perry Johnson, Inc., 1986

Statistical Quality Control Handbook, Western Electric Co., Inc., 1959

Quality Control and Industrial Statistics, Charbonneau and Webster, 1978

Introduction to Statistical Quality Control, Montgomery, 1985

Statistical Process Control, Chrysler Corporation, Ford Motor Company and General Motors Corporation, 1995

Professional groups that publish manuals and booklets about SPC are the:

American National Standards Institute

American Society for Quality Control

American Society for Testing and Materials

More information

    SPC chart types.

    About Statistical Process Control.