The symbol shown in the ladder diagram can be thought of as a contact that is...

Getting back to the original gist of this thread, I believe that young programmers-to-be are not starting with the basics. They want to jump right into programming when really they should be actually be wiring on actual real world relays, PBS, and limit switches.

IMO, this would help with understanding NO & NC contact terminology.

Of all of the naming suggestions, XIC, XIO, Examine On, & Examine Off have to be the most confusing. Yuck!!
 
I like to point at a ] [ and say, "if that's on" and point to a parallel ]/[ and say "or that's not on"…
On to me means logical 1.
I went to SC back in my uni days and the accents and vernacular were quite pleasant.
 
In regards to XIO and XIC....
If I am not examining the contact is it still working?

I still think "Normally Open" and "Normally Closed" should be the standard. Just seems to make more sense.....
 
The symbol IS EQUIVALENT to a Normally Open electrical contact.


there are only 10 types of people...those who understand binary, and those who don't.
 
Normally Open and Normally closed define the state of relay contacts when the coil is not energized or sitting out on a table top. PLC "ladder" logic was meant to represent Relay Ladder symbology. If it is followed through, it is all consistent.



So if I wire a NC-stop-pushbutton to an input and a NO-start pushbutton


being consistent means you would program something like (I do not use the seal-contact!):


STOP START motor

--|/|----| |----( )


Thats not logical to me.....



Of course, a pushbutton is not a relay though, is it?
 

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