Studio 5000 AFI Always False Input vs JMP LBL to Disable Rung
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- เผยแพร่เมื่อ 26 ต.ค. 2023
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This is the best illustration I have seen. I create a test bit, now I need to re think how I disable logic.
I'm glad it was helpful. I have had many people send me good test code asking what is wrong and when I ask them how they disabled the old code, I find out they stuck an AFI in front of it which as the problem.
You just saved me hours of troubleshooting! I will be JMPing in my current program for extruder controls Monday morning. Thanks Tim!!!!
Glad it helped!
It's completly insane the easy way do you explain this simple but powerful differences betwen each instruccions, thanks for the great video! Greetings from Mexico
You're very welcome!
Solid point Tim, I appreciate the honest viewpoint.
I like to stick with these foundational elements.
-Achieve the scope of work
-Make it reliable
-Make it easy to read for the person behind us
This at the very least.
Again, I appreciate your videos and your view on things.
Thanks for sharing!
Simply the best instructor. Thank you Tim. Linked in brought me here. 🎉
Awesome, thank you!
One of the best videos from Tim. Great presentation.
Thank you, you made my evening 😁
If I ever come back to the states I am buying you a beer.
🍻
i’m glad you showed this. definitely cleared up a misunderstanding for me
Glad it was helpful!
I really wish there was a single instruction equivalent to a // in ladder. That said, it might do unintuitive things when used within a branch.
I was surprised when the green light was flickering. I always thought the code is executed, and at the end of the scan was when the outputs were applied to the real world. I lean stuff quite often from you. Glad you have a physical device you are working off of.
I'm going to do a follow up next week but the I/O and continuous task are not executed in sync
Also, some people have made some other suggestions that you may find helpful
That's Fire, I love it thanks, Tim
Glad you like it!
This is also a good example of what they taught me in programming about having double OTE’s in that the rung 0 is true for that output but will not light the output since rung 1 is false. Last rung wins. I see double OTE’s cause a lot of headache if not caught.
Oh no, you didn't say the last rung wins...th-cam.com/users/liveUVNxBrErl9c?feature=share
Love these tips, learned something new
Glad it was helpful!
Great videos. I learn a lot from you. Couldn't you place the AFI at the beginning of the rung you want to disable? Thanks
No, that's exactly what I explained DIDN'T work in this video.
Thank you Tim for the great video. I am still wondering about the light is flickering. There is still something I do not understand. From what I understand RPI is the request packet interval that the module has to be updated. Since the program is so simple, it should be updated within the RPI time. Another point is the toggle bit function, it will affect the logic depending the bit location before it is updated (coil) in the program. I did some tests before. I cannot really recall.
The scan is asynchronous so sometimes the output is updated after rung 0 and sometimes after rung 1. It does spend more time on the 2nd, hence why changing the positioning of the rungs affected they outcome so much
This has more to do with the fact that you are using two OTEs for the same bit rather than using an AFI. Even without an AFI that light/output would have behaved the same way unless you were pressing both push buttons at the same time.
If instead you examined the contacts of each push button with an XIC/XIO controlling a latched and unlatched bit then the AFI would behave the way you wanted. Not that I would personally write logic that way.
I have always found it helpful to think of an AFI as basically just a blocking bit, something that "blocks" the completion of the rung or branch on which its placed.
Just my thoughts from a fellow CE and someone who enjoys the content you provide.
I wouldn't do this either but enough people think it disabled the rung that it was worth talking about
@@TimWilborne Ah I gotcha. Yeah maybe it helps people think about it differently.
It looks like the flickering is caused by the yellow button rung being true in the scan cycle, then as the scan cycle continues, the light turns off due to the AFI rung. So, it's just rapidly turning on and off?
Thanks for the video. I've been wondering about the AFI myself after seeing it a lot in some programs.
Maybe I'll explain it in the next live update 😁
Hello, i love your videos. Can you explain about implicit and explicit messaging in allen bradley. Other plc has it as a data block or instruction but i cant see in allen Bradley. Thanks in advance
That would make a good video. For starters, implicit messaging is typically for IO connections that are configured in Studio 5000. I remember this because "I"mplicit...I means IO. Explicit messaging is usually when you use a MSG instruction to read or write data to another devices.
@@TimWilborne ok I will stay tuned for that video for implicit message. Now I understand that MSG instruction is explicit.
Great video, but I'm still confused. It almost seems like the AFI is dangerous if it truly doesn't ALWAYS disable a rung, and that the GOTO instruction is a better way to go if you really want to disable a specific rung. Or am I missing something?
It doesn't disable the rung, it makes it false. It isn't dangerous. It just serves a different purpose than some people think. Here is a follow up video I did.
th-cam.com/users/liveUeI8s4oc758?si=urWQYXqYdgkTKej2
Is it possible to add a toggle bit that can turn on and off the JMP instruction?
Yes. Also here's a more detailed video about editing that may help
th-cam.com/users/liveqLXBDobuA2U?si=wftM6qDZid20tqw7
Basic Ladder Logic Rule. Never use the output instruction more than once in a program.
I agree but in these cases people were discussing temporarily testing new code on existing outputs
I watched this video because while troubleshooting problem I came across a AFI instruction at the beginning of the rung . The rung only containing MOV instructions (3) after the AFI. At first I assumed the AFI instruction was stopping the moves from executing but it appears that they still are. I since have fixed the issue. I am still curious about the AFI in front of move instructions will it stop them from executing???
Highlight the MOV or any instruction, then right click it and select instruction help. Scroll down until you find the execution diagram. It will always be evaluated as false and in the MOV's case, a false condition will do nothing.
@@TimWilborne Thanks and keep up the good work love your videos man
You are welcome.
Why not just stick a 'EQU 1 0' or a 'CMP 1=0' in the rung?
You could but at first glance, I think the AFI would be clearer. Plus not all can use a constant in Source A