Help on furthering my PLC knowledge.

[Mike F]

Hi, I am currently an electrician working within the food manafacturing industry. I have a basic understanding of a few PLC's and various software used to view information on these.

I'm looking to further my knowledge and understanding of PLC's with the hope of moving from just simple maintance and fault finding to modifications to existing programs and also eventually writing programs.

Is there any distance learning schemes people can recommend, as i have found on scan time . co . uk but they seem a little vague.

Thanks in advance

Mike

 

[topquark]

Sorry, I've never done any PLC work. They are all manufacturer specific, so find out what makes/chips you are dealing with first so you can tailor the training. You may well find some of the manufacturers offer training as well.

 

[Mike F]

We mainly use allen bradley plc and one or two S7's. I have the software for both just after some direction in this field. Many of the advertised courses, when read into seem along the lines of these 5 days domestic installer super spark scheme. I would just like to avoid these and do the proper training.

Mike

 

[topquark]

Contact Allen Bradley technical support and ask them if they offer (or know anyone that does offer) a course. Most manufacturers are keen to help folks that are using their chips.

 

[Mike F]

I have emailed them already, the other main reason i put this thread up up was that i see a few of the people who post here work with PLC's (possibly Engineer54 or Tony). I just can't find the posts, can only just about remeber seeing them.

Mike

 

[topquark]

I've just had a quick nose around on their site and there are plenty of tools and samples that you can get hold of here:
Product Resources from Rockwell Automation

 

[i=p/u]

seen a few jobs advertised that require allen bradley, plc's.... in short what are they

 

[Mike F]

They are a programmable logic controllers. Mainly used in process machinery, they work on a basis of being able to make there own decisions, dependant on program. You can program counters, timers, relays, temp controllers etc and then display set information on to a HMI/scada. In a simple form they just compress a panel buy removing items such as mechanical counters, timers etc which over time wear and need replacement.

Hope this makes some sense of things, although it is worth remembering my knowledge isn't the best on these . Hence my wanting to look further into PLC programming and the likes.

Mike

 

[Knobhead]

I’ve worked mainly with Modsoft and PL7. I tried to introduce Mitsubishi Melsec for one project but got shouted down by management that didn’t know what the hell they were talking about.

I find Modsoft dead easy to work with even when using advanced maths. It’s ladder based but you can introduce blocks for all kinds of functions. Add to which it can hold full descriptions for each node. PL7 can be either ladder or literal, again I prefer ladder as it’s easy for others to follow.

 

[topquark]

Now I need to ask: scada = system control and device acquisition? I think, what's HMI?

 

[Mike F]

HMI are the visual display units. Allow an operator to alter programmes, setting, dwell times etc.

Tony what plc's would the Modsoft software be compatable with? he programmes which i look at via RS logix/Rs linx etc are usually in ladder form and are easy to follow if you know what your are looking for.

Did you self teach or do some sort of training?

Mike

 

[dkent5]

Supervisory Control and Data Acquisition = SCADA
I was originally taught on the Mitsubishi FX series PLCs but then moved to a company that used soley the SLC 500 Allen Bradley PLCs. My company sent me to the Rockwell Automation Centre in Sutton, Midlands for the full course. You cannot beat proper formal instruction.
If you want to have a go yourself then I would suggest John Ridley - Mitsubishi FX Programmable Logic Controllers (buy from Amazon). You would need the GX Developer software where you use a simulation programme so that you don't need to go to the expense of buying a PLC. The book will teach you all you need to know about the use of memory coils, timers, all manner of counters, step ladder programming and basic ladder logic then right up to using shift data registers when you've become confident enough to try.
I have the software but don't know how to get it to you. Sorry about that. Hope this helps.

 

[silva.foxx]

Hi Mike

I've been dealing with PLCs for the last 13 years or so. I self-taught with Mitsubishi Fx then found a local night-school teaching a 3 yr course in PLC Maintenance using Allen-Bradley SLC500 so I enrolled. I moved into a job where the plant was mostly A-B plus others. So I got hands-on real-world exposure to RSL500, RSLinx and DH+. Other brands were there such as Siemens S5/S7, Omron, Keyence and Mitsi so I gained a great deal of insight into those, and got some invaluable training from Siemens too!

I'd like to recommend this series of sample lessons on A-B. Watch the lessons in order. Sample Lessons and Quizzes


Local automation companies should be able to put you in touch with courses. Some companies such as Parmley-Graham, Lockwells, LCAutomation and Routeco should find it in their interest to help!

HMIs; I have just completed a project using RedLion G3 HMIs. Fantastic. Free Crimson software on their website and good quality equipment and service.

What is your location, roughly?

 

[dkent5]

HMI = Human Machine Interface (Touchscreen)

 

[sbrown2]

Hi Mike

I'm similar to some of the guys on here. I have worked in the mining, automotive, machining and potteries and have come across an array of PLC's. Namely AB SLC500 and SL5000(I think, very old!), Siemens S5 and S7, Omrons, to small controller like keyence and festo.
You know the best training you can get, if possible go into your stores get a PLC rack, power supply, processor and input out put card or you may have a modular unit like the Mitsubishi Alpha. Power it up and practice. I did a unit on control theory when I was young and studying but from there on in when i have arrived at a company that is how I've built up confidence with PLC's. Try it if possible and if you have any other like the rest on here I will attempt to help.

PS remember the most important skills are backup and restore!

 

[netblindpaul]

HMI = Human Machine Interface (Touchscreen)

dkent,
Not ALWAYS touch screen but the mnemonic is correct!

(Ex-PLC & CNC manuf. service engineer & Ex-CNC machine tool service engineer, we had our own control systems!)

 

[Knobhead]

HMI are the visual display units. Allow an operator to alter programmes, setting, dwell times etc.

Tony what plc's would the Modsoft software be compatable with? he programmes which i look at via RS logix/Rs linx etc are usually in ladder form and are easy to follow if you know what your are looking for.

Did you self teach or do some sort of training?

Mike

I got in to programming purely by accident. The plant I was working on was one of the first in the UK to use PLC’s. They were Modicon 284’s, a few months after I joined them the PLC’s were upgraded to 984’s, unfortunately the company wouldn’t pay for new I/O racks or having the programs re-written. At least we got Modsoft instead of dedicated programming panels. We finished up with an absolute ******* of a system. One program controlled a transport system, it would loose where it had put things, lock up and refuse to do anything. The only way to get it going again was to re-load the program. This happened while I was on nights and one of the directors had dropped in for one his surprise visits. He wasn’t happy, I wasn’t happy and we argued, me saying, “this is why we want to reprogram it”. “You’d better get on with it then”. Ooopps, Tony trying to extract size 10 boot from size 8 mouth. I’ll give the company it’s due, they let me get on with it. After that I did mainly modifications.

PL7 came on to site due to management interference. I wanted to use a Mitsubishi PLC but was shouted down and told to use Modicon because everyone on site understands Modsoft, pity the Modicon TSX used PL7 instead. So we ended up with a PLC that cost 6 times more than my original idea and no one had a clue how to program. It was purely trial and error getting the system working.

Have a look at http://www.barn.org/FILES/historyofplc.html

 

[netblindpaul]

Tony,
Your link mentions one of my previous employers!
The one where the guys dropped all the kit on the floor.
I spent 10 years working for them in various roles, most of it on field service.
One of the resons that Dick was unsuccessful was the tie up with Cranfield Uni in the UK where by Landis developed their own combined CNC & PLC control for the EU & American markets with their own funcitonality.
Though we did use Siemens, Fanuc & NUM also.
The PLC is only part of the automation story though is it not?

 

[Knobhead]

Some of the plants I worked on had some weird and wonderful control. One controlling a kiln was a 1960’s Feranti Argus 1000 computer complete with punch tapes and Teletype desk. It fell out of favour when it turned the fuel to full and closed the exhaust damper.

Other plants used hard-wired logic Solicon being the first followed by Logicon 1 and then Logicon 2. Rack after rack of individual logic units. In a way better than the PLC, logic was solved in real time and not governed by scan cycle. An absolute swine if you had to make any alterations!

Our first venture with PLC’s was with Texas Instruments, not a great success due to the scan cycle and reliability but we got around it. These were followed much later with Mitsubishi, they be came the standard on the works.

 

[Steve1412]

Local colleges usually run decent courses using mitsi FX or Allen Bradley SLCs they are reasonably cheap...If you go for manufacturer specific courses expect to pay £250 a day at least. The basic principles are the same in ladder logic but different software handles things in different ways.