types of PLC!HELP ME GUYS!

could someone please describe variouse types of PLC and suggest a range of applications for each, and giving reasons for your choice of applications!!??!! this would help me out greatly as im on a plc course and am stuck on homework! please post back asap thankyou

go to Search in the blue bar above, type HNC, and you will find dozens of threads from blokes in your very predicament.

Warning, some of the responses are blunt.

Brian.

cheers brian, im finding it very hard to get answers on the net.

Well... Most plc manufacturers have a plc that will do almost any job required.

But being in the trade for over 20 years & with a lot of experience the following may help.

Mitsubishi: these have a good range of plc's from the micro range upto the new "Q" series.

The micro range are the brick (FXON) useful for small apps less than a couple of dozen I/O, the FX2N range, these are small to medium application plc's, useful for small conveyor, batching or pick & place machines (like palletisers etc.) & can have upto 256 I/O with analogs, comms & special units like steppers, however the memory is limited to a few Ksteps so beware.

The "Q" series was meant to be their answer to the big ones like siemens & AB, however these have a lot more memory but even the largest the Q25 only has 64K onboard & not really for complex batching processes.

The Siemens range go from brick type plc's (a few I/O) to the larger S7 400 series, these are the real workhorses that have plenty of memory, loads of functions built in & lots of interfaces.

AB have again a full range from bricks to the newish control logix platform, these are serious processors with loads of memory & rival Siemens.

There are loasds of others, some pretty well known like OMRON, IMO & are fairly good, but be aware of some of the more "Cheap" stuff going, the support is poor, functions lacking & few people know them.

These include Koyo & others, not to say these won't do the job but as they only have small outlets it's best to stick with the better known ones. After all you can get the smaller Mitsi, Siemens & AB from RS the next day as they carry the stock.

http://www.freestudy.co.uk/plc/

See: Assignment 1

I think this is the first time I've done this, toddy. You won the lottery because of your good manners and indications you have done some work yourself.

parky said:

but be aware of some of the more "Cheap" stuff going, the support is poor, functions lacking & few people know them.

These include Koyo & others, not to say these won't do the job but as they only have small outlets it's best to stick with the better known ones. After all you can get the smaller Mitsi, Siemens & AB from RS the next day as they carry the stock.

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Ouch..I sure hope Mike dosnt see this one !!!

Forget what was said about Koyo..ie automationdirect.com they can compete with anyone on familiarity and delivery, for many years they made plcs for some of those "name brands" that were mentioned.

The link Tom posted will probably offer the most information required for the HNC course.

Side note; some should read the question and take the time to understand the question. The question was not "What brands are there and what is your favorite brand(s)."

parky said:

These include Koyo & others, not to say these won't do the job but as they only have small outlets it's best to stick with the better known ones. After all you can get the smaller Mitsi, Siemens & AB from RS the next day as they carry the stock.

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Hmm... I know for a fact that I can get a koyo (automationdirect) anywhere in the US and Australia tomorrow just by calling their phone number... I've done it several times... What would you have to go through to get any other brand CPU, card, etc to Moree Australia or Red Springs North Carolina tomorrow?

Blasphemy!....Grrrr.....

parky said:

There are loasds of others, some pretty well known like OMRON, IMO & are fairly good, but be aware of some of the more "Cheap" stuff going, the support is poor, functions lacking & few people know them.

These include Koyo & others, not to say these won't do the job but as they only have small outlets it's best to stick with the better known ones. After all you can get the smaller Mitsi, Siemens & AB from RS the next day as they carry the stock.

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Parky, will all due respect your greatly missinformed about Koyo/AutomationDirect. My guess is you have little or zero expierance with AD.

Koyo was the manufacture for the GE Series One, TI & Siemans 305 & 405 product lines. Koyo is the parent company of Automationdirect.com which still supports these units. We've been using AD almost exclusively for more then 10 years.

As the cost of the PLC represents only about 5-10% or so of the cost of our projects, COST was not the major factor in our decision to switch to AD. Rather it was the HIGH quality of the product, and the superior and hassle free support provided by AutomationDirect. If your stuck on a jobsite and need support NOW you can get it my calling a toll free number, and within a few minutes your talking to a knowlegable support tech, who will gladly answer stupid questions and hang with you for hours if necessary, (been there..done that). Support is totally free, (including the phone call).

99.999% of what they offer is usually in stock 100% of the time and can be on your desk or at your job site the next day. If you order from AD by 5:00 pm, you can have it in your hands by 8:00 am the next morning. How much better do you want it?

The problem is your equating quality with cost. AD is one of thoes rare instances where this is just not the case. The low cost comes from not having to spread the profits through a complex distrabution network, not by pawning off an inferior product.

I will tell you I was pushed and proded for months to give AD a shot. In an effort to quell the noise I agreed to try it on an in-house project. Within two days I was completely sold and never looked back.

</rant>

Parky's reply was from a UK point of view. AD are pretty much unheard of over here.
As the original question was from someone based in England it would be misleading to tell him he could get great support for AD products.

toddy324 - what course is this and where is it being held ?

What would you have to go through to get any other brand CPU, card, etc to Moree Australia

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Not a problem with Omron, Hitachi, Mitsubishi and a few others. AB not so good because the distributors do no carry enough stock. GE a pain in the "A" - I waited for 7 months for a quote on a repair. Siemens - doubtfull.

Potter said:

Parky's reply was from a UK point of view. AD are pretty much unheard of over here.
As the original question was from someone based in England it would be misleading to tell him he could get great support for AD products.

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That's funny, just the other day I talked to a guy in Wales on the PHONE. That seems to me that it's highly likely that GB has PHONE service that is somehow connected to the rest of the planet.

Obiviously both you and Parky have internet service also...www.automationdirect.com

Bonus!! Even though some of the guys in Cummins GA. have a slight southern drawl..they do speak pretty good English.

However if your looking for local support you might check here: http://www.lamonde.com/

toddy324 said:

could someone please describe variouse types of PLC and suggest a range of applications for each, and giving reasons for your choice of applications!!??!! this would help me out greatly as im on a plc course and am stuck on homework! please post back asap thankyou

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The question is very general and such will be the answer.
PLCs may be classified by their class in ascending order as follows:
- Single unit non-expandable.
- Single unit expandable.
- Modular rackless.
- Modular rack style.
PLC is a single unit if it contains the CPU and at least some I/Os. Modular ones in minimum configuration consist of more than one unit.
The typical input types are DC up to 30V and AC up to 240V.
Otputs may be relay, transistor and triac.
Typically each unit has only one type inputs and/or outputs.
Special modules may provide analog I/O, communication, networking, remote I/O, etc.

Ask more specific questions.

From my experiences:

I have used both AB (SoftLogix 5000 with a SoftLogix 5800 controller) and AutomationDirect (DL205 rack with H2-WPLC) and found that both worked very well. The major differences for any PLC are the delivery, support, programming environment, and capability (application dependent).

With both brands above I have next day delivery if I want it. Support for AB is local and support line while for AutomationDirect it is only telephone support.

Programming environment for the two is as different as night and day!

OldNovice