adccommunitymod (AutomationDirect) asked a question.
Proper rung constrution
Created Date: May 16,2005
Created By: bartb102
**** This post has been imported from our legacy forum. Information in this post may be outdated and links contained in the post may no longer work.****
I am wondering about proper rung construction for a DL450 (or similar) PLC- I think I remember reading someplace that all rungs must have at least one contact in them, i.e., unconditional rungs are not allowed- | SP1 |---| |----------(Y1) is legal but | |----------------(Y1) is not Anybody know for sure? thanks
Created Date: May 16,2005
Created by: bartb102
I am wondering about proper rung construction for a DL450 (or similar) PLC- I think I remember reading someplace that all rungs must have at least one contact in them, i.e., unconditional rungs are not allowed-
| SP1
|---| |----------(Y1) is legal but
|
|----------------(Y1) is not
Anybody know for sure?
thanks
Created Date: May 16,2005
Created by: bcarlton
The second construction inherits the true/false state which existed at the end of the previous rung. That's probably not what is intended. If you want an 'always on ' state then use a contact which has that value as the condition.
Created Date: May 16,2005
Created by: RHanrahan
I have used the second condition only if it immediately follows a Stage. Otherwise I use the first condition. The only real advantage of the second condition is that it saves one step of code.
Bob
Created Date: May 16,2005
Created by: bartb102
Another difference between A-B & Koyo. In A-B each rung stands alone.
Thanks.
Created Date: May 16,2005
Created by: bartb102
The unconditional construct is useful if there are several rungs in a row that use the same conditional, a MLS/MLR can control all of them.