No & nc

Join Date
Sep 2015
Location
Melbourne
Posts
29
Hey Guys,

I need 2 NO and 2 NC outputs on a PLC, how do I assign them, the input part is pretty clear to me (NO switch for NC contact and NC switch for NO contact).

How do I assign NO and NC as I require two of each.

Thank you :nodi:
 
Mate, you must be a pro. and I respect that, I am trying to learn something new, if you can't help, atleast do not discourage.
There are many people around here who started from scratch, you must be a born talent, I ain't.
So, please troll someone else.
Ta
 
Wrong attitude to get an answer here..

What PLC are you referring to?
 
I need 2 NO and 2 NC outputs on a PLC
Are you talking about physical output devices? Most PLC contact output modules are strictly NO, although you may be able to find some vendors that offer form C contact outputs. Until prompted by Boneless, you failed to specify the brand and model PLC you're using.
If you truly need a normally closed contact, the simplest solution is probably to wire the PLC output to an interposing relay and wire the relay's contacts to your field devices.
On the other hand, you may be talking about the use of NO or NC contacts within your ladder logic...
the input part is pretty clear to me (NO switch for NC contact and NC switch for NO contact)
Be careful with your assumptions here. They could get you into trouble. When you're talking about hard-wired PLC inputs, regardless of the physical device to wired to the input point, a normally open contact instruction in ladder logic evaluates as true when there is current flow at the input point's terminal and false when there is no current flow.
 
Mate, you must be a pro. and I respect that, I am trying to learn something new, if you can't help, atleast do not discourage.
There are many people around here who started from scratch, you must be a born talent, I ain't.
So, please troll someone else.
Ta

EDIT: People got ahead of me while responding.

You're question smells like homework, and we get that a lot around here and we don't do homework for people. Your question lacks any details of what your platform is, or details as to what you have done so far, what worked what hasn't. You posted a vague question and expect us to magically read your mind. Garbage in = Garbage out.

The 'pros' here are very willing to help, especially people who are trying to learn and make it obvious as to the effort they are putting in. A sign of respect for our time is to see that a post contains quality effort into question, and a good description of what platform you are using, what you have done so far and what your results have been. The 'pros' see the effort put in, and will go to great lengths to reciprocate.

Of course if the post is clearly a poor effort, expect poor responses.

I kindly suggest that you check the attitude, and use the that time to provide more detail. You'd be surprised what you can learn here if that is really want you want.
 
Do you really need NC outputs (closed when the PLC power is off)?? If you do it will require an external relay. Essentially all PLC outputs are NO.
If you just need logically NC outputs you will have to write them that way. The type of PLC you have will determine what is required. Omron supports a normally closed output.
 
Thank You, that help a lot, the interposing relays seems to present a clear way.
Guys, I am sorry that I was unable to post a clear question, and yes it did come across a bit obscure, but I am truly inclined towards being an automation engineer and learning PLC programming inside out.
I really appreciate the help I get from this group.

The application in picture is a truck turntable with two positioning sensors (Pepperl-Fuchs R2100, RS 232 com) , the output comprises of an alarm and a stop signal, directly to the VFD.
PLC: OMRON CP1L 40 I/O

P.S. Its been 15 days since I've been acquainted with a PLC, and my company refused to pay a single dollar on the required training, but nevertheless it a new skill set for me, and I am happy to do what ever it takes.
 
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