XIO/XIC vs. NO/NC

My mind simply cannot grasp the XIO/XIC terminology. I just stick with NO and NC.

I learned to program PLCs with a handheld Boolean keypad, so I've always thought of the NO and NC relay contact symbols in RLL as "ANDs" or "AND NOTs" when in series and "ORs" or "OR NOTs" when in parallel.

I have no problem with the XIO/XIC nomenclature, but it is brand specific to AB.
 
I learned to program PLCs with a handheld Boolean keypad, so I've always thought of the NO and NC relay contact symbols in RLL as "ANDs" or "AND NOTs" when in series and "ORs" or "OR NOTs" when in parallel.

I have no problem with the XIO/XIC nomenclature, but it is brand specific to AB.

Yes, me too. I forgot about using "AND" or "AND NOT". That is a very clear way of stating it. I'm tired.
 
For XIO's I've always used the term "true if off". Also the tag can always be thought of as using the word "not" in it, like a "Unit in Auto Mode" XIO could be Unit NOT in Auto Mode if the XIO is green.
 
My mind simply cannot grasp the XIO/XIC terminology. I just stick with NO and NC.

I don't know if this has already been said in this huge thread, but a potential problem with using NO and NC is when they are used with real, physical, PLC inputs.

A "NO" instruction could be inspecting the state of a "NC" field contact, and vice versa. This has huge potential for being confusing.

I believe that A-B, back in the original designs, were aware of that, and deliberately chose XIC and XIO over NO and NC to try to alleviate that potential confusion.
 
I don't know if this has already been said in this huge thread, but a potential problem with using NO and NC is when they are used with real, physical, PLC inputs.

A "NO" instruction could be inspecting the state of a "NC" field contact, and vice versa. This has huge potential for being confusing.

I believe that A-B, back in the original designs, were aware of that, and deliberately chose XIC and XIO over NO and NC to try to alleviate that potential confusion.

I agree with you. Another side if this whole discussion is that the description should indicate what’s happening when it is on, like “Ram is Down” or “Motor is Running”. It drives me crazy when something is just described as “Transfer Limit Switch” or “Elevator Solenoid”. Don’t make someone guess.
 
..........I believe that A-B, back in the original designs, were aware of that, and deliberately chose XIC and XIO over NO and NC to try to alleviate that potential confusion.

Actually, I believe they originally called it “Examine On” and “Examine Off”. That made more sense to me than XIO and XIO. Different stroke for different folks.
 
geniusintraining
I miss Ron. He would tell it bluntly like it was.

Yep he was big personality and liked sticky up for what he thought was right


harryting said:
Whatever happened to Terry? I think he was the one who said he would fire people who spent time on the internet at work.

I think he got fired and that was the last we heard of him ;)

Just kidding, I did have a few conversations with him after he was 'gone' and he said just was getting tired of the 'same questions' over and over, his son got a acting job in a sci-fi movie and he was proud of that... boy he could get people to think

I remember once he talked about PLC code that could change its own code and rewrite itself needed... still would of loved to see that, that was the start of AI :cool:
 

Similar Topics

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...
Replies
8
Views
5,971
Hi, I am using an AB PLC5. I have a rung with three branches on the right, so that it has three connections to the right (output) rail...
Replies
10
Views
7,138
This is a long, double-post explanation of XIO and XIC. It goes through the full derivation of the concept and ultimately ends with a...
Replies
46
Views
42,707
Hi, I am new to plc and i was reading the contensts in plcs.net. I have a doubt. i am not able to understand when we should go for normally...
Replies
4
Views
5,887
I'm new to the TotalFLow XIO and it has an attached TFIO DI/DO combo module. All I'm trying to do is close an output on the TFIO module. I'm...
Replies
3
Views
600
Back
Top Bottom