smart relay or PLC?

bob1371 · Sep 2, 2003

Hello

I have a project coming up with 3 CNC machines. We are adding Keyence sensors to detect misset parts. Each machine will have 8 sensors, however I only have 2 Inputs available per machine. I have a few options that Im looking at.

1. Daisy chain them thru relays.
2. Small brick PLC.
3. Smart relay.

Im wanting to use a plc, however we MUST (NOT MY CHOICE) use mitsubishi so that throws out a couple of the cheaper models.
(did I mention they want this done for ZERO BUDGET)

I really hate going with the relays so my next option was a
smart/programmable relay. I havent used these before and just looking for a few recommendations.

thanks,

Bob

rsdoran · Sep 2, 2003

Personally I dont see the cost difference in using a smart relay compared to some small plc's. The strong point about smart relays is the software is included or can be download free an example is HERE and its not necessary to have software to program.

If the company is adamant about using Mitsu plc's and you need to use something low cost then I think the smart relay may be a good choice.

AB makes an 10 point micrologix thats around $99 and has free software. http://www.ab.com/plclogic/micrologix/

Fuji also has plc's starting at $81 with free software<this is a link

BTW: The is a place http://www.plccenter.com where you can buy used plc's etc for half the standard price.

Danocane · Sep 2, 2003

It's difficult to recommend a particular method to your application. With ZERO Budget you just have to look around and see what will fit and what you are willing to support.

I have to agree with Ron on the differences between Small Brick PLCs and Smart Relays. At least with one of these you can attach your sensors to the inputs and write the logic you need, then use a couple of outputs from this device as signals to your CNC machine.

Here are some links for various brands where you can download more information.

Allen Bradley Pico Controller

IDEC Smart Relay

Zelio-Logic Smart Relay

Genesis Programmable Relay

E10-npn : The World's Smallest Ladder Programmable Controller

Klockner Moeller EASY412 & EASY600

Alpha Micro controller by Mitsubishi

Hope this helps...

Thanx Dan

panic mode · Sep 2, 2003

Note that not all of them use same programming language.
For example Alpha Controlers from Mitsubishi use function
blocks. Although they are more powerfull than many other
similar products, you will be VERY frustrated to program one
of these using only buttons and little display that is on
PLC. Software is very easy to use but it's not free
and you might want the programming cable too (believe me
you don't want to make this one at home).

bob1371 · Sep 2, 2003

Thanks for all the input. I checked out each link and will be getting a couple quotes. I may be able to sell them on the micrologix as we do have a couple of those running in the plant. I would really like to use something different as that allows the opurtunity to learn.

thanks again

Bob

LadderLogic · Sep 3, 2003

You may also check Omron ZEN: http://oeiwcs.omron.com/webapp/commerce/command/ProductDisplay?prrfnbr=131153&prmenbr=316

elhagan · Sep 3, 2003

i used all smart relay

dear sir
if you good in ladder you must bay mooler
if you not good bay zelio is eazy and smol and i send to you haw to
used it

dont used mooler
dont used allan
dont used ge fanu
used zelio or omron

Eric Nelson · Sep 4, 2003

Re: i used all smart relay

elhagan said:
dont used mooler
dont used allan
dont used ge fanu
used zelio or omron

I wish someone told me that 20 years ago... lolis

Bob, since you "MUST use Mitsubishi", you may want to see if they plan to release a smart relay in the near future. There's a good chance it will probably just be a 'brand labeled' version of one that already exists. IOW, if you buy, let's say, a Moeller (or mooler

) today, eventually you may be able to buy the EXACT same one, with the only difference being that it will now have the 'required' Mitsubishi logo on it.

I wonder what cute name Mistubishi will call THEIR smart relay...

beerchug

-Eric

bob1371 · Sep 4, 2003

Thanks for all the input. I decided to go with the IDEC smart relay. Hope it was a good choice.

Bob

CaseyK · Jul 6, 2004

Eric wrote:

I wonder what cute name Mistubishi will call THEIR smart relay...

The answer to me is obvious..

It would be an "Itsy Bitsy Mitsi"

and maybe not....casey

CaseyK · Jul 6, 2004

Eric wrote:

I wonder what cute name Mistubishi will call THEIR smart relay...

The answer to me is obvious..

It would be an "Itsy Bitsy Mitsi"

and maybe not....casey

rdrast · Jul 7, 2004

Not that it really applies here right now, but Smart Relays really don't seem all that useful anymore to me. I do like to carry one in the bottom of the toolbox for those wierd, on-site problems, but the cost is actually getting out of line with some amazingly powerful, and tiny, PLC's.

Again, not my primary choice, but I have used several of the Aromat/NAIS FP series PLC's. Ultra fast, ultra tiny, networkable, and A CPU with 16In/16Out can be had for less than the cost of a smart relay.

smart relay or PLC?

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