difference between LOCAL,REMOTE

hello

welcome to the automation world. my name is M.S.N.Rao. i am recently joined as a plc programmer. now i am in the beginning stage. my doubt is LOCAL, REMOTE. Actually Local input means the inputs which are in the cpu backplane. and remote inputs means the inputs or outputs which are in the expansion means with out having the cpu. Buat actually we are using one selector switch LOCAL, REMOTE. So my doubt is what is the difference between this local,remote and that local,remote. If any one knows please give a breaf explanation about it to here or my mail id. then i am really thankful to all and this site

with regards

m.s.n.rao

My first response is that switch is to allow control from a local station or from a remote control room.

Hello m.s.n.rao,

In (my) opinion local is a I/0 that is "local" just that, I don’t know what PLC you have so I will show you using AB

In this pic I;1.0, I;5.0 are local inputs (wired direct)
The high lighted one I:9.0 is a Remote input using a RIO scanner, this is another back plane without a CPU that has one cable going from the scanner on the main backplane.

So now there is one cable running from the Main to the expansion





In this next PIC is the I/O config screen #9 is the remote scanner 1-8 are local




There are other ways with different PLC, you can use other meens of communication ie.Ethernet, Profibus, Etc,

Hope this helps

Mark, you gave a great explanation on local and remote I/O. I wasn't sure what he was asking but it sounded like there is a selector switch somewhere that is labeled LOCAL and REMOTE. I'm pretty sure that has nothing to do with the way I/O are defined in the plc and when he noticed this SS, he got confused. I was trying to tell him that just because there is a switch with the local/remote label, it can mean many different things, most of which has nothing to do with the plc. His best bet is to look at the circuit and see where the SS goes.

brucechase said:

I wasn't sure what he was asking

Click to expand...

Bruce,

I too did not have a clue what he was asking, but I figured you got the selector switch...I would try and cover the other, together we might of helped him

The word local means "HERE"

The word remote means "SOMEWHERE ELSE"

If its about IO, then it means IO that is here (this chassis) or somewhere else (another chassis)

If its about function, it means something that is operated from here (local) or something that is operated from somewhere else (remote).

Think about your television for a second. You have buttons on the set itself. And you also probably have a remote control. Unlike your TV, in industrial situations sometimes there is a selector switch to enable/disable control from another location.

Alaric said:

Think about your television for a second.

Click to expand...

Are we watching American Idol?

Aralic,

Usually when you chime-in I shut up and learn, but this time I had to reply...Your analogy sucked, a TV? Like I have said in the past, you are 10 times the programmer I ever want to be, but that’s just funny