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Understanding Inputs and Outputs for Specific Project

  1. Nov 25, 2015 #1
    << Mentor Note -- Please read to the end of this thread -- important information about AC Mains connected projects is discussed >>

    Hello everyone,

    I am an electrical engineering student (though in the very beginner stage of it), and I could really use some help with understanding inputs and outputs of a device.

    My college's S.T.E.M. club is building a ring launcher, but we plan on making it display more of the levitation aspect of it (which is to say we do not want to launch it, but rather keep it in a levitating stage for roughly 30 seconds). We are all very inexperienced in almost every concept of the project, but are taking it on to learn as much as we can. At this moment, I have a pretty solid understanding of the way the actual device works, and most of the unseen forces at work. The thing I am struggling with, is understanding how to program certain functions into the display without taking on circuitry completely. (I simply figure that making something work once is much different than building a long lasting and safe circuit).

    After much research, I have come across "Smart Relays" from companies like IDEC, and they look very promising for accomplishing the goals we have, which I will list below. The biggest problem is that I don't know if I am understanding the website's listing of input and output correctly.

    It states the following:
    Product Type: CPU Base Module
    Operating Voltage: 100-240 VAC/DC
    I/O Range: 50
    Input Channels: 8
    Input Voltage: 100-240 VAC/DC
    Output: 4
    Output Type: Relay
    I/O Expandable: 9 modules

    Then it lists key features as:
    Key Features
    • 10A Relay Outputs
    • Built-in Real Time Clock
    • Optional Text Message Display panel
    • Function block or Ladder programming
    • New USB programming cable
    • Worldwide approvals � cULus, CE, FM Class 1 Div 2, Lloyds Registered, and ABS approved
    My understanding is that the device can be hooked up in this fashion, 120V outlet > breaker > button > smart relay > two separate ring launchers, and I would like to ask for verification or dismissal (with explanations). I also see it as the device can handle 120V input, and output 10amps (If this is true, please help me understand how much energy I am actually putting into the ring launchers, and if it still equates to the same as simple plugging them into a wall).

    As mentioned above, the goals for the project are as follows:
    -Button is pushed
    -Power is turned on for the devices for 30-60 seconds
    -Buttons, knobs, misc can be pressed to activate the ring launchers
    -Once the 30-60 seconds is up, power is shut off for 30-60 seconds (cool down period)
    -Once cool down is complete, power can be supplied again (with button press), and cycle repeated.

    Could I also get verification that the smart relay can handle this with some program adjustment.

    Thank you for your time, and hopefully I explained this properly. The main thing we want to avoid is creating our own circuit(s) because to actually understand what we are doing completely with the circuits would push our timeline pretty far back.
    Last edited by a moderator: Nov 27, 2015
  2. jcsd
  3. Nov 25, 2015 #2


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    Staff: Mentor

    Welcome to the PF, and great first post.

    Sorry if I missed it, but could you post a link to the part you want to use?

    And could you post a schematic diagram of how you plan to hook this all up? When you include AC Mains connection in your projects, we want to understand that you are making safe decisions about those connections.
  4. Nov 25, 2015 #3
    Thank you for the reply.
    To be clear on the schematic, I am not sure of proper notations/design. I hope to come away knowing exactly how to correctly draw a schematic though. I did a rough mock up, but it likely does not give an accurate representation, and I know it excludes many details I have seen on other schematics. It is a cross of some circuit work and typical wiring, so again, sorry in advance. [I have attached the picture]. If anyone has a good reference site for learning these basics, as well as truly beneficial materials, I am absolutely up for learning it all. I just need a place to start that won't steer me wrong.

    As for the "Smart Relay," here it is.

    We absolutely want to understand exactly how the electricity is flowing exactly, and all safety aspects before even purchasing any materials.

    Attached Files:

  5. Nov 26, 2015 #4


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    Nice drawing, it helped a lot.
    The Smart Relay may be a good choice, but I'll have to review the manual. The USB interface looks cool. The input channels will let you control behavior.

    What are all the functions that the Smart relay will have to perform?

    Right now it seems to be
    1. "When button pressed, supply power for X seconds, then force no power for Y seconds" where X and Y are selectable.

    Can you add the power source to your drawing? Maybe show the relay contacts?
    Do the launchers run off 120AC?
    Can you post a link to the purchased launcher?

    Have you looked into time delay relays? Maybe there is a simpler (but not as flexible) approach using those.
  6. Nov 26, 2015 #5
    Thank you.

    The absolute minimum is for the goal you stated. We would also like to make sure by pressing the button (for supplying power), the timer for X does not restart. Another goal is to leave open a door for additional features if time allows. We have talked about introducing a motion sensor to turn on lights to really make the display caught the eye of those walking by.

    I drew up a different picture after doing more researching last night. It shows the actual intentions of the smart relay, and my understanding of how things must be hooked up. I think I am starting to understand the concepts better, but I don't know the physical elements at all right now. For instance, I am not sure how one can hook up power to L1, input 1, input 3, output 1, output 2, output 3, ect. [See attached photo]

    [Note: In my picture, I forgot to draw in a link from Output 3 (2) to L1.]

    On the website, the ring launcher says it is 115VAC, but is plug and play. To my understanding, that is essentially the 120VAC, just with a variable adjustment.
    Link: https://sargentwelch.com/store/catalog/product.jsp?catalog_number=WLS1755-85

    Lastly, I came across the timer delay relays briefly, but it seemed like I would essentially need a relay for X and a relay for Y. If any extra feature were to be needed, a third relay might be needed, and so forth. I might of not understood how they work correctly though. I'm quite comfortable with programming logic, and the idea of feature expansion is why the Smart Relay (PLC+Relays) seemed like the ideal fit.

    Please let me know if the design I drew up is correct, and if not, please inform me of my mistakes (please read note mentioned above).

    Attached Files:

  7. Nov 27, 2015 #6


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    The FL1E-H12RCC works with AC. , Seems like a well engineered robust product. I think it is a good choice.

    I'd fuse the launcher feed also (L1). Was that a "typo"?

    Does the motion sensor need a fuse?

    Generally you need a 3 prong plug with hot, neutral, and ground. But the Relay only has L1 and N inputs.
    You probably want to carry ground to the launchers. (there is no data sheet for the commercial launcher)
    Not sure how to advise you with regard to switch selection, electrical code and proper wiring. Be best if you consulted a licensed electrician.

    Otherwise, seems pretty well thought out from a purely functional point of view.
    I have not looked at all the logic elements in the relay and determined you can do all those things, but it all seems reasonable.

    Again, I stress the need to to consult with an electrician when working with power mains.
  8. Nov 27, 2015 #7


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    Staff: Mentor

    Since this is for a school project, do you have a supervising instructor who can advise you on safely working with AC Mains power?
  9. Nov 27, 2015 #8


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    The more I think about this, the less I like it. From a functional point of view it is a good solution, but MAINS power in an Educational setting is just NOT a good idea.

    I would NIX the mains based approach if I was the adviser.

    A safer, more robust approach would be to use a low voltage smart relay (from the same family). Power it all from a 12V supply, and use it to switch external relays at the launcher.

    I would build the system such that the launchers could be plugged into switched power.

    I really don't like the idea of developing a process in a school environment based on imaginative use of mains voltage. I see kids rewiring using the components for new projects. It's not safe.
  10. Nov 27, 2015 #9
    I put L2 to potentially power it with the second outlet plug, but that was with hesitation. I will absolutely look at the ground being carried to the launcher, and any other routes it may need to take prior or after.

    I will also be sure to talk with a licensed electrician about all aspects of the project.

    I think this would be much better, but I don't know if I understand completely. Would you have any links to the concepts of switched power? I tried doing a quick look into it, but found several very different things. Would the switched power be a middleman of sorts with a trio link between outlet to launch and smart relay to launcher? (That is what I am picturing, but I just don't know what it is yet).
    Last edited: Nov 27, 2015
  11. Nov 27, 2015 #10
    The Adviser is one of the college's Physics professors, and our school does not have very many professors with electrical backgrounds. We are meeting next week with two of our electrical engineering professors, and are looking to arrange meetings with various electricians with and without connections to the college. No matter what our route ends up being, we will not let ego or excitement overshadow the fact that we are inexperienced. We are looking to take every safety precaution, and do not want to move forward until we are sure all preventable hazards are taken care of.

    Our projected deadline is April 29th, 2016, so we have time. The actually production of the display is estimated for two weeks (due to availability), and we would like all supplies in hand five weeks out from deadline. The rest of the project is about learning and understanding all elements that are going into the display.
  12. Nov 27, 2015 #11


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    I was thinking along those lines. A 12V relay (maybe solid state?) operated by the smart relay to switch the mains.

    Something like this in an enclosure with a mains plug, fuse, mains socket and a connector to the smart relay.
    http://www.mouser.com/ProductDetail/Omron/G3NE-220T-US-DC12/?qs=lK7M36XCk6J4X%2f1Lr%252bSoww%3d%3d [Broken]

    Here is an example using that part:

    Maybe the manufacturer of the smart relay has similar products.

    I just noticed it was the "college" STEM club, so sorry about the "kids" remark.

    You have a lot to review and think about.

    I'm at the edge of my competency with this industrial control stuff. perhaps someone else will chime in.
    Last edited by a moderator: May 7, 2017
  13. Nov 27, 2015 #12


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    Staff: Mentor

    Please have your advisor send me PM and I will re-open this thread. There is value in discussing AC Mains sarety regulation compliance -- it's hard to deal with it in an Internet forum, and we struggle with it here. You really need a local mentor to help you learn how to comply with really important NEC and UL safety regulations (in the US -- other agencies are involved in safety approvals in other contries)...
    Last edited: Nov 27, 2015
  14. Nov 27, 2015 #13


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    BTW -- I was lucky to have my summer job at a major elecronics company between my junior and senior years, and had several mentors help me build my first AC Mains connected personal project -- a lab power supply. I learned what UL regulations governed products that were connected to the AC Mains (both single-insulated and double-insulated products), and what I needed to do to make my DIY AC Mains connected project safe. Please do not try to build DIY AC Mains projects without a mentor like that.
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