Looking for a PLC / General Science and Electronics / Forums

Forums

4hv.org :: Forums :: General Science and Electronics

« Previous topic | Next topic »

Looking for a PLC

previous 1 2 3 next

Move Thread

LAN_403

Steve Conner

Sun Jan 15 2012, 10:12AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Sure, but what use is an Arduino for learning about PLCs?

As mentioned before, PLCs work with a different paradigm to computers and uCs. To program "Ladder logic" you basically enter the wiring diagram for the relay logic that does what you want. To computer people this seems beyond retarded, but it's the industry standard.

When you consider that PLCs were designed to take the place of boxes full of relays, contactors and timers, it makes perfect sense.

Patrick

Sun Jan 15 2012, 10:16AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Steve Conner wrote ...

Sure, but what use is an Arduino for learning about PLCs?

As mentioned before, PLCs work with a different paradigm to computers and uCs. To program "Ladder logic" you basically enter the wiring diagram for the relay logic that does what you want. To computer people this seems beyond retarded, but it's the industry standard.

When you consider that PLCs were designed to take the place of boxes full of relays and contactors, it makes perfect sense.

yes ill agree connor, if he needs to learn ladder logic, and can afford Allen Bradley, then go for it.

doctor electrons

Sun Jan 15 2012, 03:47PM

Registered Member #2390 Joined: Sat Sept 26 2009, 02:04PM
Location: Milwaukee Wisconsin
Posts: 381

I have a whole bunch of allen bradley micrologix plc's at the moment! You can also get
the software (light version that is) from rockwell automations website. I would let some of them
go. If you are interested ill post a picture of them. All of them use rslogix and rslinks and
they are self contained units. Cpu and i/o in one package.

Zum Beispiel

Sun Jan 15 2012, 05:35PM

Registered Member #514 Joined: Sun Feb 11 2007, 12:27AM
Location: Somewhere in Pirkanmaa, Finland
Posts: 295

Thanks for the suggestions. What I'm really looking for is a PLC though, I'm not looking to homebrew something with microcontrollers or such. I was hoping that someone who has worked with automation systems before could suggest a good model for me.

doctor electrons: I'm interested, but I think shipping might be a problem. Throw a PM my way and we'll see.

Patrick

Sun Jan 15 2012, 11:39PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

doctor electrons wrote ...

I have a whole bunch of allen bradley micrologix plc's at the moment! ... I would let some of them
go.... All of them use rslogix and rslinks and
they are self contained units. Cpu and i/o in one package.

Zum, this is the way to go if you can make a deal with doctor electrons. the last time i used Allen Bradley was 10 or 15 years ago, they make good stuff though. If you can get one of the fully self contained units, for a less than new price, then your set.

Zum Beispiel wrote ...

...What I'm really looking for is a PLC though, I'm not looking to homebrew something with microcontrollers or such. I was hoping that someone who has worked with automation systems before could suggest a good model for me....

get with the model type and number that doctor electrons has CPU/IO fully integrated, for home automation and your other requirments, youll get everything youll need. i dont think you need the seperate IO and CPU's... I presume the ones he's offering you have 10 or more I/O's, I cant remember the
model or type numbers...

doctor electrons

Mon Jan 16 2012, 03:16AM

Registered Member #2390 Joined: Sat Sept 26 2009, 02:04PM
Location: Milwaukee Wisconsin
Posts: 381

Micrologix 1000 is the model of the ones that i have. However... There are different features within the
1000 family. I have 120vac power, and i/o. I also have 24vdc power and i/o. I also have 120vac power with 24vdc i/o.
If you can describe what you are going to be hooking up i can probably set you up with one that will suit your needs.
I also think i have one that is strictly relay outputs so you can use 120 or 24 on the output side.

Zum Beispiel

Mon Jan 16 2012, 11:28PM

Registered Member #514 Joined: Sun Feb 11 2007, 12:27AM
Location: Somewhere in Pirkanmaa, Finland
Posts: 295

It will probably be a few light gates and motion sensors and anything else I might think of, really. I'm pretty sure I will only be needing digital inputs, though a few analog ones wouldn't hurt I suppose. Relay outputs would be nice, those are probably harder to break, in any case. The controller will be switching relays or contactors anyway. 24V supply voltage sounds fine.

I haven't had a chance to take a look at the datasheets for the 1000 series yet, but I'll try to take a look tomorrow.

doctor electrons

Tue Jan 17 2012, 03:13AM

Registered Member #2390 Joined: Sat Sept 26 2009, 02:04PM
Location: Milwaukee Wisconsin
Posts: 381

Have a look and let me know! Happy to help you out if i can!

randommscience117

Wed Jan 25 2012, 04:16AM

Registered Member #4274 Joined: Mon Dec 19 2011, 03:10AM
Location:
Posts: 47

Check out here:

They have a big selection of click PLCs for under 106â‚¬ at the most expensive. I have a contact there that could give you more information on their PLCs.
Here's another website on the PLCs

Hope that helps!

Carbon_Rod

Wed Jan 25 2012, 07:39AM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

X10 is UL approved for home use, and a network dongle kit (works on the Pi) is under $50...

Being able to read ladder logic is a good skill to have, but anyone who infers these PLCs can do anything special is not knowledgeable in this area.

Rockwell / AB modules usually have a very aggressive licensing policy, and in some factories people simply bolt on a "decorative" unit to the side of new machinery so they comply with the terms.

Proprietary hardware in most cases is worse... given 10 years from now... some clueless Junior engineer will be on eBay trying to source replacement parts that don't exist.

The stacks in many SCADA systems are currently placing entire lines on the "depreciated" technology replacement list... So more cheap PLCs on eBay soon..

People should learn ANSII C, non-compiler specific macro syntax, and secure linux networking...

Even the next Windows servers will come in headless versions similar to most *nix systems...

previous 1 2 3 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob