Sequencing parameters and program parameters

The configuration that differentiates a sequencing parameter from a program parameter is as follows:

A sequencing parameter is part of the set of values that must be provided to a sequence program to make a product. A sequencing parameter must have its

Sequencing

attribute set to TRUE. This restricts the parameter’s usage and data type and prevents the parameter from being a constant and having an alias. A sequencing parameter is visible outside the sequence as part of the sequence’s interface to other coordinating programs.

A program parameter gets its value or makes it value available to other parameters in other programs. The usage is less restricted than sequencing parameters, and may have almost any data type, be a constant, and have an alias. A sequencing parameter may be a program parameter.

Program parameters are useful for making status values (equipment status or processing status) available within the sequence program while maintaining data encapsulation, a good programming practice when sequences are run by other programs.