RSLogix 5000 XIC, XIO, OTE, OTL, OTU (Beginner Question)

[rockets1989]

I am a beginner at RSLogix 5000 and in ladder logic in general. I am tasked with making sense of an existing program and reprogramming it to make it more efficient. I have a few questions.

1. I have a BOOL Tags named "PSC1107A_BLOCKED" and "SIDE_A_BLOCKED" that have a value of 0. In one of the rungs on the program it looks like this


When a value of 1 is written into the tag "PSC1107A_BLOCKED" from an OTE somewhere else in the program, will the XIC get toggled (turn green) and the XIO untoggle? If so, won't both the OTL and OTU "SIDE_A_BLOCKED" become energized? Is this bad programming or is there a fundamental of ladder logic that I am not aware of?

I asked someone that I work with to explain it to me and he said that these parallel branches are a way to make the OTU "SIDE_A_BLOCKED" stay true until the XIC "PSC1107A_BLOCKED" goes true and the OTL "SIDE_A_BLOCKED" goes true. In this explanation, the toggling of the XIO acts as a jumper until the "PSC1107A_BLOCKED" writes a value of 0. But this doesn't make sense to me since there will be two values for a single tag.

2. (Question not associated with the image) A rung has an OTE that is toggled because the tag has a value of 1. When this rung goes true, does the tag associated with the OTE receive a value of 0?

3. Same question as Questoin 2 except asking about a toggled OTL instead of toggled OTE. What happens to the value of the tag after the rung goes true?


Thanks

 

[Mickey]

See link.. Click on sample lessons and videos.

http://www.ronbeaufort.com/main_frame_page.htm

http://www.plctalk.net/qanda/showthread.php?t=61692&highlight=green+power+flow

http://www.patchn.com/index.php?opt...d=58:xioxic-explained&catid=20:plc&Itemid=118

 

[robertmee]

You have a fundamental msunderstanding...an xio and xic of the same tag will never evaluate true at the same time. So either the branch with the otl or out will only be true...not both. The green you see shows powerflow through that xio because the tag is 0...

 

[Mickey]

You have a fundamental msunderstanding...an xio and xic of the same tag will never evaluate true at the same time. So either the branch with the otl or out will only be true...not both. The green you see shows powerflow through that xio because the tag is 0...

Not power flow but there is a "1" in the "bit box" ( A Ron Beaufort description) at that address.

See link...Read the whole post

http://www.plctalk.net/qanda/showthread.php?t=61692&highlight=green+power+flow

Edit: I added some links to my previous post.

 

[Mickey]

Not power flow but there is a "1" in the "bit box" ( A Ron Beaufort description) at that address.

See link...Read the whole post

http://www.plctalk.net/qanda/showthread.php?t=61692&highlight=green+power+flow

Edit: I added some links to my previous post.

I stand corrected...

teaching so time is short - but ...
Quote:
Not power flow but there is a "1" in the "bit box" ( A Ron Beaufort description) at that address.
that statement should be a "0" in the bit/box ...

actually "green on the screen" for an XIO would (generally) indicate TRUE logic because of a ZERO in the bit box ...

so ...

the XIO would tell the processor to "go look for a ZERO in the bit/box" ... and if it DOES see a ZERO then the instruction would be evaluated as TRUE ... and (generally) would turn green ...

so how's everything out your way? ...

best regards ...

Ron
__________________

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Ron | |
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I once was lost, but now am found, was blind, but now I see.

 

[robertmee]

It is powerflow and the bit box is zero as I think you corrected yourself with the next post. Ladder is symbolized by a power rail on the left and common/ground on the right as it of course evolved from relay logic. The green is showing TRUE and hence powerflow through that instruction.

 

[proof]

He told you wrong. If your goal is to simplify, the logic does the same thing as an XIC(PSC1107A_BLOCKED) OTE (SIDE_A_BLOCKED); XIC(PSC1107B_BLOCKED) OTE (SIDE_B_BLOCKED); It is only copying the bits. They only reason that the existing method would be 'better' would be if there was logic that was changing SIDE_A_BLOCKED somewhere else in the code.

 

[rockets1989]

Thank you all for your messages. I realized by all of your inputs what I was misunderstanding. Thanks for your swift responses and taking the time to look at my post. I will keep on working in RSLogix 5000 and soak up as much as I can day by day

 

[Bering C Sparky]

Thank you all for your messages. I realized by all of your inputs what I was misunderstanding. Thanks for your swift responses and taking the time to look at my post. I will keep on working in RSLogix 5000 and soak up as much as I can day by day

Rockets,

First off Welcome to the Forum and to the world of automation. (your in for a fun ride)

Secondly, the gentleman that Micky spoke of "Ron Beaufort" teaches PLC classes and has many youtube videos available for you to watch and learn from.
Check the videos out and you will gain much from them very quickly and they will help put you on the right track. (Just Google "Ron Beaufort Youtube" and they should come up)

Also if you have a little coin and a little time available (5 days) I can highly recommend you look into taking Ron's class on Logix5000. It is well worth the time an money and will put you light years ahead.

It is called PLC Boot Camp, check it out at this link.

http://ronbeaufort.com/

BCS