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ABC Technical

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Does anybody here have or had anything to do with Pro Logic Controllers?

All the machinery at my place has these & to be perfectly honest I havent got a clue where to start getting info, or how to fault find/replace/test etc, etc. :_|

Any help will be appreciated chaps ta very muchly. :)

 

kme

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Big, fast, multi trace scope. :x

logic probe. ; \

Multimeter, :x

Schematics, ?:|

PatienceX(

Luck:_|

In equal measures, on the odd occasion I`ve had to go near the things! :_|

Can`t be much more help, I`m afraid, :( other than to say that the fault finding process is purely logical:| - literally m8. You have to think every step through, to check that everything it expects to have happened has or did, in the right order, before it proceeds. X( :_| X( :( X( :_| :eek:

Hope thats of SOME help ?:| - if you get a particular problem, come back for my

"I dunno, mate" - blurb:^O:^O

 

DonkeyDong

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What make and models do you have ?

What is your remit for support ? If one breaks you simply replace it ? Or are you expected to program them ? Add extra inputs/control circuits or output circuits ?

D.

 

ABC Technical

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KME, thanks mate, might have to write a shopping list for work to pay. :)

DonkeyDong, I have no idea mate, will check what make/models next week.

As for the rest of your question I have not been asked to look at anything yet.

I just want to try & get some idea of what these things do, have looked online & so far only found the actual PLC thingymajig's, no other info. :(

It must be somewwhere, I bet I am looking in the wrong place.

 

Davun

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Hi ABC,we have a lot of PLC stuff at the recyling plant i look after and i have on the odd occasion had to check them out.

PLC's do make things a lot easier and save a lot of space,basically its a computer and a load of switches or relays that open and close to the tune of the computer :^O

Anyway,i've only one had to get a chap in to go through the actual coding of the PLC ( called the LADDER program ) not really a very friendly place to be in !

If you keep the supplies on and the battery backups good then you never need any reprogramming.

PLC's are not to keen on changing temperatures and damp weather can cause havoc with the contacts where the modules plug in.

You main problems would be with process devices,like detectors ,photo electric eyes ,solenoid valves and electronic switching,all of which is your basic fault finding stuff.

There are programs run on the net to learn ladder programming if you want and how to diagnose PLC faults,it usually involves you or your company stumping up a large wadd of cash :^O

In a nutshell - its the stuff thats attached to the PLC thats the problem.

Good luck bud

Davun

 

kme

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Would concur - the old computer GIGO (garbage in=garbage out).

The comp, correctly programmed and non faulty, behaves like your pc is doing now - you type something, and it displays / posts it.

You type nonsense, that`ll be what comes out.

The "shopping list" is for the PLC unit itself, but, as Mr. Davun states, you`ll usually find either a peripheral sensor / relay causing the issue.

Bit like "my car won`t start". You`ve got an engine management CPU, but that rarely goes nipples up - it`s more likely one of it`s sensors.

HTH

 
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