Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

Stop Light Program Help

Created by: Shodai at: 4/18/2019 9:24 PM (6 Replies)

Rating (1)

Thanks 2

7 Entries

4/18/2019 9:24 PM	Rate (0)
Shodai Posts: 4 Rating: (0)	I have been working on putting together a stoplight program; nothing fancy just trying to learn. However, no matter how I approach the process I keep running into the same error, "Recursions only allowed via outputs and flags". I am working in Ladder and would like to keep it that way. There has to be a way around this, but I cannot find it.
Shodai Posts: 4 Rating: (0)
Suggestion To thank Quote Answer

4/18/2019 9:29 PM	Rate (0)
ixo65 Grandmaster-Expert Joined: 12/18/2014 Last visit: 12/4/2023 Posts: 31545 Rating: (3920)	There are other ways, but these are easiest with flags or outputs. You know what a recursion is?

Suggestion To thank Quote Answer

4/18/2019 10:59 PM	Rate (0)
Shodai Posts: 4 Rating: (0)	My understanding of recursion from computer programming is a form calling a function from within that function. Often times repetition is involved. I guess my bigger question would be what is a flag? Since that is an option it might be an appropriate solution.
Shodai Posts: 4 Rating: (0)
Suggestion To thank Quote Answer

4/19/2019 7:02 AM	Rate (0)
ixo65 Grandmaster-Expert Joined: 12/18/2014 Last visit: 12/4/2023 Posts: 31545 Rating: (3920)	A recursion in LOGO! Soft Comfort is the signal feedback within a circuit program path. And LOGO! Soft Comfort only allows this via outputs and flags. A flag is a virtual output in LOGO! Soft Comfort (see attachment). Attachment LOGO! 8 manual 0BA8 2017_11 xxxx8-0BA0 pages 127-128.pdf (114 Downloads)

Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users Shodai

4/19/2019 2:47 PM	Rate (0)
ixo65 Grandmaster-Expert Joined: 12/18/2014 Last visit: 12/4/2023 Posts: 31545 Rating: (3920)	Here some examples for a digital recursion. Attachment Recursion.PNG (110 Downloads)
	Last edited by: ixo65 at: 4/21/2019 4:20:03 AM Last edited by: ixo65 at: 4/23/2019 3:25:33 PM Attachment
Suggestion To thank Quote Answer
This contribution was helpful to 1 thankful Users Shodai

4/19/2019 8:31 PM	Rate (0)
Shodai Posts: 4 Rating: (0)	Thank you so much the information is very helpful. One last question though; everything seems to be in function block diagrams, is there a way to do it with ladder diagrams?
Shodai Posts: 4 Rating: (0)
Suggestion To thank Quote Answer

4/19/2019 8:38 PM	Rate (1)
ixo65 Grandmaster-Expert Joined: 12/18/2014 Last visit: 12/4/2023 Posts: 31545 Rating: (3920)	Yes, you can make a program in LAD. But in LAD not all functions are available to you as in FBD. For example, network projects can only be programmed in FBD.

Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on