Program parameters are a powerful new feature in Logix that allows the association of dynamic values with tags and programs as parameters. The importance of program parameters is clear by the way they permeate the user interface in newer versions of Logix Designer (version 24 and higher). Program parameters are extremely powerful, but the key benefit to us in using them is that they are automatically buffered. This means we can effectively create the same result in one Ladder Logic rung that we did with the eight we created in the previous section.
There are the following four types of program parameters:
- Input: This program parameter is automatically buffered and passed into a program on each scan cycle.
- Output: This program parameter is automatically updated at the end of a program (as a result of executing that program) on each scan cycle, similar to the way we buffered our output module value in the previous...
