Hello all!

Hi Emma! Welcome to the group. It is widely varied but mostly confined to terrestrial control problems.

If you would like to ask specific Spaceflight questions, if you haven't already, may I suggest you also look at news:sci.space.tech (specific technical questions) and news:sci.space.moderated (more general questions) - some of the people there (eg. Henry Spencer, Jorge Frank and Rich Katz) do spacecraft control and flight dynamics for a living and many of the other posters are recognised experts in that field.

Cameron:-)

Thanks for that Cameron. I am also interested in terrestrial applications, Spaceflight just seems particularly interesting at the mo. I posted to the sci.space.tech site at the same time as I did this one though hadn't found the moderated group yet.

I am interested in terrestrial applications, Spaceflight just seems particularly interesting at the mo, and I'm a little worried that the Control Systems on my course won't go into quite enough detail for me to be at an advantage in the work place when I graduate so I figured it might be an idea to try and develop some particular expertise! This seemed to be as good a place as any, though I think it'll be a *little* while before I understand everything that is being discussed here. It is nice to get an insight into real life applications and developments on here which is limited on my course.

questions) -

Emma,

Controls for space craft involve setpoint changes in a benign environment. They also have extremely good system models available. Applications respond well to good math.

Industrial controls involve constant setpoints with unpredictable external disturbances. The system models are usually poor to non-existent. Mathematical analysis is of limited value.

Setpoint or servo control vs. regulator control. The two are very different. What you learned in school is far more relevant to the former. Process industry is very messy but it pays well.

Walter.

applications,

Emma, I don't post a lot to this board, but if I can offer you any advice if you are looking into Controls as a field here it is. (By the way, this is not a complete list.)

-look into some PLC training (if you don't already have some). Local distributors offer training all the time.

-find out what sort of plc hardware is used in your geographical area (call your local electrical distributor and ask them what hardware companies are using.)

-research the products that are available from the desired manufacturers

-make sure if you want to work in an industrial setting (a lot of control jobs) you have a good base of electrical knowledge. I don't mean you know Maxwell's Equations or Ohm's Law. I mean you understand

3 phase power and how control circuits fit into the system. You should know what a VFD is and how it works. You need to know how a Reversing Starter works.

-Communication Protocols are important too. You don't need to know every detail, simply what protocols are out there and how to use them.

-Analog communications. You should know a little about 4-20mA and

0-10V. Advantages and disadvantages of each. How to implement current/voltage loops using a PLC.

I teach a PLC nightcourse at a local college, and I see it every time. I get Electrical Engineers who graduate and don't understand real world electrical systems. You are more marketable if you are field smart and not just book smart.

Andy

Excellent advice. The man is right on.

Walter (30 year pro.)

applications,

message

Hi,

Thanks guys, this is exactly what I was hoping for - I knew there were holes in my course, I think it covers a few too many areas in not quite enough detail but now that I know what they are I can do something about it. Think taking a year out is gonna will turn out to be a good move. :-)

Emma

Rather disturbing to me. I went to school to get a BSEE and am clueless in this area. Graduated in May and control systems and microcontroller programming interest me more than anything else in the field, but I've never heard of VFD or reverse starters before. I've been considering working through the second half of my controls text (the class spent over 50% of our time on the first quarter, reviewing Laplace transforms for the MEs). I took a PLC class (which wasn't actually part of my EE degree, but I worked in my school's automation lab and was interested in learning more about them), and the concepts presented in the course were crystal clear, but instead of working on more complicated and diverse lab assignments, I found myself squeezing larger and larger programs into smaller and smaller memory areas with strict design criteria, and having meetings to discuss the design in which we were all ultimately forced to follow the professor's template in the end anyway. The class felt mostly like busy work, but did teach me the basics of PLCs. I never heard of using a current/voltage loop with one though, so it bothers me to think that I may still be quite a ways away from being useful even in the PLC programming area.

Glad I'm not the only one who is in this boat. Would love to learn what I need to know before I go where I need to know it though.

applications,

message

Variable Frequency Drives (Someone please tell me if they're not :-) ) though they never came up on my course - I did a little background research on them during my DC Motors class. I know a little about Starters but not Reverse Starters.

My course covers PLCs but not in enough detail that it could really be applied in reality :-( . What really worries me at the mo is that my course has not covered 3 phase power (except to mention their applications). My course isn't an EE course or a SE course. Obviously it covers aspects of each but i'm a *little* concerned that if I don't cover the extra material I'll struggle to find a job in either area.

(^^^^^ Sounds familiar!)

A lot of graduates from my course go into Mobile Telecommunications and very few to the Control Industry (which surprises me as it is essentially a Control Course).

I would like to point out, that I am not involved in any embedded work or software engineering. I am strictly involved in larger scale industrial control. My experience is in Water Treatment (clean and dirty) and Automotive manufacturing. I worked for an electrical contractor out of school so that I could develop my hands on experience. If you are interested in embedded control, then I am not the person to listen to.

A great resource for information would be

(Allen Bradley website). Here you will find all sorts of printed material. On the left hand side, you will find 'A to Z Product Listing'. Click on that and you will come to a page with all the Allen Bradley products. If you want to investigate VFD (Variable Frequency Drive), then click on 'Drives' under 'Drives & Motors'. In there, on the right hand side, you will find a link for 'Literature'. Click on the 'On-Line Publications' link. In here, you will find all the Drives that are available. Pick a drive (I use a lot of PlusII's and Powerflex 70's) and look at what it does. The same goes for all equipment. This opens up a whole new ball of wax, as there is a tonne (metric of course) of information here (including old junk that isn't used anymore). If you are new to all this, then I would look at the brochures that are available. They will fill you in on what these devices do. Start very general. You don't need to know the engineering behind a VFD, but merely how it works within the big picture. Then you can research how to program them and what settings are important/common.

I think the best resource would be to go to as many trade shows and seminars as you can in your first couple of years in the business. If it's being offered, you should be going. This will help you develop a picture of what is being used in industry. Then you can go back to the Allen Bradley website and better understand what you are looking for.

If you have specific questions, ask them here. I'm sure someone will answer them.

Andy

Hello all! Where do you draw the line between Control Systems Engineer and Electrician? Engineer covers everyone from a plumber (sanitation engineer) and a railway engine driver to the guys who designed the space shuttle. When I worked as an electrician/panel wirer I dealt in star-delta starters, VFDs and PLCs, high speed counters, limit switches, proximity switches, light beam sensors and safety cut outs etc etc. The Control System Engineering degree I took at university didn't deal with electrical control, but rather with design of control items you wouldn't expect all electricians to be capable of (No offence meant. I worked as and with electricians and have yet to meet one I didn't like and respect). Laplace transforms and control theory, frequency response, electronics, software, to design flight control systems or electronic engine controllers or active suspension or . . . I'm told, that if you get a degree in an engineering discipline, this is supposed to prepare you for the first step towards engineering and project management. You choose. The problem is, I guess, no course at college or university can fit everything in. So you end up continually learning and doing courses on safety and management and motivation and new systems for organising the job better and better design tools and . . . Of course, its this continual learning that keeps the job interesting. Best Regards Mark (Just my 2 cents)

"Andy" wrote in message news: snipped-for-privacy@posting.google.com...

news:...

You must be from UK. In Canada the word 'engineer' has a very specific meaning. With the exception of a few specialized cases such as railway or recording, 'engineer' means university degree plus professional license. Of course in the media technicians get promoted to engineers and engineers to scientists but this is not common usage.

Walter (engineer)

Electrician?

Emma,

Next time be more specific when naming your topic. For all that, you've just gained an agreeable and competent bunch of down to earth buddies.

Find a job where you need a hard hat and toolbox; it will bring marketable skills and even more endearment and respect.

For some material from the trenches look at:

Some of the articles herein are updated versions of the monthly Heating Highlights Column in Process Heating Magazine, Bensenville Illinois. (processheating.com).

Who can benefit from these articles?

1. People in the broad field of processing heating, who are mathematically or time limited and have to deal in short order with various control problems - among their many other jobs.
2. The overloaded customer-support desks of control equipment suppliers. Incoming queries are rarely specific and detailed enough. The caller is often unfamiliar with this technology and its vocabulary; so sending out these primers can avoid phone seminars and long dialogs with the help desk.

Arthur Holland

I do mostly embedded control, neither process control nor spacecraft, although some of my control loops are in devices attached to aircraft. I learned my most useful material from three places:

1. Control systems classes. You _do_ need the theory somewhere in your brain, even if there's no math to pin it to.
2. Electrical Power and Electrical Machines courses. If electricity goes in and torque comes out you'd like to know what's going on in between. Take these courses when and if you can.
3. Installing air compressors and repairing furnaces at my Dad's shop. Granted they were tiny motors by Walter's standards (only 10 horsepower), but one learns about 3 phase power, where to jump when the motor starts the wrong way, what 110 volts feels like and other useful things.

I think the biggest comment that I can make is that you can't go anywhere with just control theory. If you don't understand what it is that you're controlling you'll never make it work. You'll find that the people around you may understand what they're asking you to control, but they won't speak control system language, so you can't just ask for a system model (assuming it can even exist). This means that _you_ have to learn _their_ job, at least up to a technician's level. It also means that you'll need to do it again and again, unless you settle into one little niche industry.

Furthermore, you have to be willing and able to push back on other people's designs. Like it or not the "systems" is in "Control Systems" for a reason. Folks will often design their part without really thinking about all of the details of how it fits with the rest of the system. You'll come in at the tail end and people will say "hey! There's the control engineer! She'll fix everything!". There will be times when you'll have to make someone change something. It may be someone who outranks you and started at the company before you were out of diapers, and you'll have to forceful enough to get it done while still being diplomatic enough to retain your job.

If this still all sounds like fun, then you're on the right track.

-- snip --

LOLOL! I was vague for that very reason :-) To be perfectly honest I don't know what area of Engineering I want to go in to. I know I like the control theory side of things - Laplace, Modelling, Transfer functions, Fourier (OK so I don't really like that one so much), Simulation etc. I also like drawing pretty pictures (Graphs) in MATLAB and Simulink ;-). However, I've been keeping my eyes open for the last few years for what Control Jobs are around in the UK and there seem to be relatively few compared to other Engineering Disciplines. Most of the jobs that are available seem to be industrial control/Petrochemical/Offshore etc (and very few design jobs) and I do feel I need to develop additional skills to get a foothold in these areas. Bought a book by Hughes yesterday (Electrical and Electronic Technology or something like that) which will go towards plugging those gaps and further my Electrical Power/Machines background.

Yes I am from the UK where the term 'Engineer' is applied very looseley in many circumstances 'Engineers' do not receive the respect that I have witnessed in many other countries. In fact most people I have met from a non Engineering background consider an electricial to be an Engineer - often an 'Installation Engineer' which I do not agree with. In fact I saw an advertisment in the newspaper the other day for a 'Communications Engineer' (Secretary) *raises hands in despair*. I will not consider myself to be an Engineer until I have graduated with a professional qualification (MEng for me) and become Chartered which will take about four years in Industry (Is that what you mean by professional license - we do not have a license as such). I do however agree that you can be an Engineer without going to University as mentioned; you can be an Engineer by trade as opposed to profession - I think the railway was a good example.

Emma,

I didn't notice the 'Emma' part. My daughter is Emmi. She just graduated in chemical engineering.

I think it was in this thread that someone complained they didn't have a clear idea of electrical power. Simple, let me quote from my web site, "Electricity is smoke. It is produced by burning coal or oil in power stations. They burn the fuel to make smoke and the smoke is pushed down the wires to the appliances in your home. Then the smoke goes back to the power station on the other wire and is let out the stack. The worst thing you can do to an electrical appliance is to let the smoke out. Once the smoke gets out, the appliance will no longer function. Sometimes you can fix the leak with tape but usually it is too late. Even worse is if the smoke gets out in the middle of a wire. Then it will set your house on fire. Toasters let out just a little bit of smoke in the form of hot air."

The best way to get started is to start. You'll learn a lot soon. More than you possibly can any other way. I started as draughtsman. I wasn't very good but I learned that the symbol that looks like this -||- is not a capacitor. It is a relay contact. I was laid off after a couple of months but that little bit of knowledge got me my next job. During the interview I was shown a drawing that said "Motor Starter Wiring Diagram" in the title block. When I was asked what the drawing was I said, "It's a motor starter wiring diagram." I kind of figured out the rest. Then I was shown a complex matrix. I was asked if I knew what it was. Again I read the title block. I said, "It's an Emergency Shut Down Key." I was asked if I could read it. The column on the left said things like, "Separator V-12 high level." The row across the top said things like, "Separator inlet ESDV-101". At the intersection of the two lines it said, "CL". I took a wild chance and said, "When there is a high level in inlet separator V-12 you close the Emergency Shutdown Valve 101". And this how I started in a 30 year career. Actually I didn't have a clue what I was doing but I hung on just long enough to find out. That is how most control systems engineers get started. Gregory Macmillan wrote a whole book on that subject, "How to be an Instrument Engineer". It is sold by ISA.

Yes, in Canada P. Eng.; is about the same as chartered engineer in UK.

Don't knock process control. You get to play with BIG toys.

Walter.

Oh, one more hint -- That second job I got by answering an ad looking for EEs with THREE years experience. "If only I had three years experience", I dreamed. Then I figured that maybe the old hand with THREE years experience might need a helper. So I applied. There was no three year guy available till about three years later. Then it was me.

Walter.

Headhunters will tell you that right now customers are asking for near impossible combinations of background.

Well then perhaps there is hope for me after all!!!! I think that is something that my course does cover. What type of combinations do you mean?

experience",

Recent graduate with twenty years experience.

History of loyalty to employer and willing to relocate to other continents within a week.

Fully qualified but not smarter than the boss.

Good sense of humour but doesn't read Dilbert.

Walter.