Prerequisites

• Access to the Management > Collection tracking (SP004) menu.
• Previously created data collection.

Introduction

This configuration changes the way SPC calculates the control limits of the characteristics. By default, the system is configured with "Fixed calculated limits", but there are other options available:

Variable calculated limits

Indicates when not all readings of the samples are filled out. The control limit is calculated based on the number of filled-out readings, generating a limit in the plateau format, rather than a straight line.

Fixed calculated limits

The system calculates control limits based on filled-out samples. Thus, it is necessary to enter at least two samples in the collection.

Fixed limits

Allows the user to establish limits as needed. In this option, it is necessary to define the lower control limits (LCL) and upper control limits (UCL) for the average (X), range (R), and standard deviation (S) charts. It is also possible to enter an objective Cp.

Customizing control limits

1. Access the Management > Collection tracking (SP004) menu. 
2. Select a collection. 
3. Click on the button. 
4. On the Characteristic tab, select a characteristic. 
5. Then, click on the button. 
6. Select the way to calculate the control limits. 

7. To finish, click on the button.

Conclusion

This article has shown you how to customize the control limits and the limit types available on the system. For further information on the other configurations, refer to the Configuring a characteristic for collection article.