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Newbie request

Former Member

Hi Guys,

          Just joined and would like to ask a question about feasibility. I have been in engineering all my working life and need to pick your expert brains to see if what I am proposing can be done with an Arduino. I have built a waste oil swimming pool heater that works pretty well manually but now I have to automate the controls. I need to control 240v ac pumps, a pre-heater circuit, an igniter, some solenoid valves and also monitor temperatures and flame detection. There are various fail-safe sensors to consider also such as flow switches and pump after-running in the event of flame out. Ideally I would like the system to attempt to relight 3 times after which it all shuts down and needs a reset after investigating/rectifying the lack of igniting. It all seems to be a question of logic control with multiple inputs and outputs and relays in series and parallel. I know this is just a brief summary of what is required with no flow diagrams etc but just wondering if this sort of project could be handled with either an Arduinio Uno or Due/Raspberry Pi before I attempt to butcher an existing waste oil heater and pull all the guts out to incorporate in my set-up. Any help or advice gratefully appreciated. If you need more info about what needs to happen and sequencing I can let you know as I have been working on the specifics for some time.

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  • 0

    Russ,

              As per peter's reply these industrialized PLC's with the correct add on modules will certainly provide a good basis for your system.  Like Peter I have to mention my previous career, I worked for Kodak Ltd and did a lot of work with machine control systems. I worked with Modicon, Seimens and Allen Bradley.  The Seimens Logo is a much more modern version and a good deal more compact.  The major advantage of these PLC's is that they have in built protection on the I/O's.

    However, I do not think it would be half as much fun or as much of a challenge to 'home brew' a system with Arduino.  Challenge is the word but I do think that what you want to could be done with an Arduino or similar but definitely with some external signal conditioning circuitry.  There is also a question of cost and I do not imagine the Siemens system will be cheap.

    It is 10 years since I worked on PLC's but at that time they were not used as point of safety controls so if you do go that route (PLC) then you may need to consider some external interlocks.

    Please keep us posted how your project unfolds especially if you want help / suggestions for the Arduino route.

  • 0 in reply to bobcroft

    Hi Russ,

     

    I just saw your post and thought it sounds really interesting.  Having read through the post, I find myself disappointed that you've decided to go with a PLC.  Not that it won't do an excellent job for you, and will be pretty robust without any intervention on your part, I must second Bob's comment that the hombrew solution can be just as robust and much more satisfying.

     

    I suppose it depends on what you want.  If you're after crafting something, then I'd say leave the PLC alone and go with the Arduino type solution.  A raspberry pi or an Arduino due are also sledgehammers for this type of application.  I reckon you could do it on an 8 bit controller like a PIC16F87X or an Atmel ATtiny.  In fact, I'm sure you could.  You mentioned the UNO - that's probably the easiest and most appropriate place to start.  As long as you've got enough IO, it should do the job well.

     

    I've many years experience, in the Automotive realm, designing IO front ends for reliability and robustness.  It's not expensive but it does take a little bit of thought.  Much more fun than buying in a ridiculously expensive PLC...

     

    As for safety, you will have to design in some dedicated interlocks.  I wouldn't rely on any electronics to keep things safe, unless you're going to make it a redundant system.  Even with DMR you might still want interlocks.

     

    Good luck.  I'd be happy to help if I can.

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  • 0 in reply to bobcroft

    Hi Russ,

     

    I just saw your post and thought it sounds really interesting.  Having read through the post, I find myself disappointed that you've decided to go with a PLC.  Not that it won't do an excellent job for you, and will be pretty robust without any intervention on your part, I must second Bob's comment that the hombrew solution can be just as robust and much more satisfying.

     

    I suppose it depends on what you want.  If you're after crafting something, then I'd say leave the PLC alone and go with the Arduino type solution.  A raspberry pi or an Arduino due are also sledgehammers for this type of application.  I reckon you could do it on an 8 bit controller like a PIC16F87X or an Atmel ATtiny.  In fact, I'm sure you could.  You mentioned the UNO - that's probably the easiest and most appropriate place to start.  As long as you've got enough IO, it should do the job well.

     

    I've many years experience, in the Automotive realm, designing IO front ends for reliability and robustness.  It's not expensive but it does take a little bit of thought.  Much more fun than buying in a ridiculously expensive PLC...

     

    As for safety, you will have to design in some dedicated interlocks.  I wouldn't rely on any electronics to keep things safe, unless you're going to make it a redundant system.  Even with DMR you might still want interlocks.

     

    Good luck.  I'd be happy to help if I can.

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