I persist with my efforts to "reverse engineer" the logic program for a vacuum process tool. This is a GE 90/30 application.
In study of the ladder logic , there are several instances where a single reference attached to a contact is used to control multiple coils, all on a single rung.
Then, in other sections of the program block, a single reference/contact is used to control multiple coil references, each on a separate rung.
What might be the "logic" to either of these approaches?
As I modify the program to add functionality of additional systems, I would like to understand the considerations and approach of the original programmer.
Your comments appreciated!
Cheers
Cal
In study of the ladder logic , there are several instances where a single reference attached to a contact is used to control multiple coils, all on a single rung.
Then, in other sections of the program block, a single reference/contact is used to control multiple coil references, each on a separate rung.
What might be the "logic" to either of these approaches?
As I modify the program to add functionality of additional systems, I would like to understand the considerations and approach of the original programmer.
Your comments appreciated!
Cheers
Cal