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Stop Light Program Help

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)
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4/18/2019 9:29 PM	Rate (0)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 1/13/2026 Posts: 36439 Rating: (4547)	There are other ways, but these are easiest with flags or outputs. You know what a recursion is?

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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)
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4/19/2019 7:02 AM	Rate (0)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 1/13/2026 Posts: 36439 Rating: (4547)	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 (317 Downloads)

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This contribution was helpful to 1 thankful Users Shodai

4/19/2019 2:47 PM	Rate (0)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 1/13/2026 Posts: 36439 Rating: (4547)	Here some examples for a digital recursion. Attachment Recursion.PNG (288 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
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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)
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4/19/2019 8:38 PM	Rate (1)
ixo65 Grandmaster Joined: 12/18/2014 Last visit: 1/13/2026 Posts: 36439 Rating: (4547)	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.

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