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Controller boards for multiple relays

Discussion in 'Microcontrollers, Programming and IoT' started by Dannybaws, Apr 20, 2015.

  1. Dannybaws

    Dannybaws

    17
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    Apr 18, 2015
    Hi there everyone.

    I'm looking for a reliable (good brand) reed relay switching board and associated PC interface.

    Basically I want to be able to control a bunch of reed relays (+5v), maybe 10 or 100 to start off, and then hopefully the ability to add more via expansions or bus network.

    For the PC interface board I'd have preferably 'PCI express' as USB is shitty, but would consider it. I would like to be able to control these relays directly from C++ commands.

    Any advice of where to look would be greatly appreciated as I'm having no luck.

    The closest thing I've found is this http://www.doepfer.de/mtc.htm but unfortunately this is controlled by midi, which is not ideal for me.

    Cheers


    Dannybaws
     
  2. Gryd3

    Gryd3

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    875
    Jun 25, 2014
    That is quite the wide range of relays to start off with... 10 to 100...
    You should also clarify what kind of requirements you need other than number?
    -Do you want to interface the device directly with the reed relays?
    -Do you want/need to be able to change the state of multiple relays at precisely the same time? (If so, how many?)
    -What frequency do you need to be able to toggle the relay(s) on/off?
    -How accurate to the timings need to be?

    Considering you've axed the MIDI interface board, have you considered DMX? It's commonly used in stage lighting and effects.
    As far as bashing USB is concerned, are you against it due to latency, jitter, or the data rates?
     
  3. Dannybaws

    Dannybaws

    17
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    Apr 18, 2015
    Good point. I mean 5-10 would do for my initial prototype, but I'd need it to be expandible to the 100s. So if there is a good board that has 10 that's fine but if there's a better one that does 100 or if it's more cost efficient to go straight for 100 i.e. not a huge price difference , it doesn't bother me either as long as it does the job well.

    I'm not sure what you mean. All I need is a way to control reed relays from a PC (using c++ commands). From what I can see this mostly requires two boards, one to send voltages to the relays, and one to control the voltages on/off, if this can be done with one board, this is fine I guess whatever is best suited.

    No particularly but I need the latency to be low as possible (<1ms preferably) and yes multiple relays (100s) being used simultaneously but they do not need to be in perfect sync with eachother, the fast speeds is what is essential.

    Nothing particularly fast. Maybe quarter of a second or something, but if regular relays are a little slower it's not a big deal. Certainly no slower than 1 per second.

    Out of interest, if I was to have a relay fast on/off cycle, surely this could potentially fry some circuits as it will be similar to holding a light switch half on, where it goes all buzzy.

    As above, <1ms, as fast as possible below this speed for reasonable price. (£6 or less per relay).

    Is MIDI quite a common interface for this purpose? If it is, I'll consider it, just want to use the most appropriate tool for the job, but as I'll be using MIDI in other areas I'd rather avoid conflicts + MIDI has certain limitations and bugs that annoy me (I use it for music). I'll look into DMX. Reliability is key.

    I just find USB (on windows at least) to be unreliable. My mac has no problem with it, but this thing will be run from a PC. Basically I've never owned a PC (and I've had many) that won't from time to time have difficulty finding the USB device and it has to be re-plugged in or put in a different port etc. I'd rather it be in there permenantly. I need it to be ultra-reliable.
     
  4. Gryd3

    Gryd3

    4,098
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    Jun 25, 2014
    I certainly understand the reliability aspect of what you are after. I have worked on a few arcade machines that simply required the USB connection for the game pad to be unplugged, and reinserted... no rhyme of rhythm as to why, but at the same time, I have never had a problem on any of my personal PCs.
    I would urge you to at least take a look at DMX, I am unsure how tight the timing is, but it's designed to control a large number of devices at a time.
    As far as a very short on/off time, with isolators and reed relays I would be concerned only if I were driving a large load. If regular relays were to be used, I would be concerned with the driving circuit for the relay and would make absolutely certain that there was protection on the board from back-emf.
    Some additional reading for you here > https://www.electronicspoint.com/threads/how-to-control-700-solenoids.273527/#post-1648647 <
    Note that the op wants to control 700 which is much higher than what you are after, but there are some good tips (specifically about a shift register)
    Some more food for thought would be considering using the Parallel port on the PC. (They are often used for CNC control for hobby machines.)
     
  5. Dannybaws

    Dannybaws

    17
    1
    Apr 18, 2015
    I've had a quick look at DMX and it looks like it runs on the R-485 protocol, which is good for me. Reliable. I will eventually want more than 700 potentially :D :D but if a limit is lower than this I suppose I could work around through software.

    Anyway, everywhere I look though all the relays are on a big board and as the numbers get larger towards 32-channels for example the price gets high.

    Surely there is a board available that sends the 5v signals and nothing else?

    So I could have the relays within the circuits I am controlling, this would save me having wires come out of the circuits only to go back in and would involved a lot less clutter I would imagine. Or is it more appropriate to have all the relays together on a board? I'm guessing if they are magnetically shielded and fit in place of the original switch there should be no issues.
     
  6. BobK

    BobK

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    If it isn't top secret, what is the application?

    Bob
     
  7. Dannybaws

    Dannybaws

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    Apr 18, 2015
    I'm afraid it is top secret :p Hate to be rude, but I can't say at the moment. When I'm finished my project in a couple of years I'll be sure to post it here :D
     
  8. Arouse1973

    Arouse1973 Adam

    5,162
    1,077
    Dec 18, 2013
    Ah.. Q was out of the lab, testing his new pen that doubles up as a parachute with laser guided missiles, so 007 had to come here for help. Don't you feel so proud that you could be helping someone from MI6?
     
  9. Dannybaws

    Dannybaws

    17
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    Apr 18, 2015
     
  10. Dannybaws

    Dannybaws

    17
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    Apr 18, 2015
    If it was an evil plan to overtake the world I could not say
     
    Arouse1973 likes this.
  11. Dannybaws

    Dannybaws

    17
    1
    Apr 18, 2015
    Oh well. Guess this thread will be closed soon. As my other thread has been. I apologise if I broke any rules. Did not realise I had to say exactly what my project is.

    It's a bit silly in my opinion as I already had sufficient answers to my question on my other thread. I have thus far managed to get perfectly good answers to my relatively detailed questions without naming exactly what I'm doing. I'm guessing the admin didn't read the entirety of my other thread. I'm trying to create something new for a business and I'm new to electronics so I did not feel I could share with the entire world. Thanks for the help everyone anyway.
     
  12. hevans1944

    hevans1944 Hop - AC8NS

    3,989
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    Jun 21, 2012
    It is quite difficult to offer specific advice when the problem is ill-defined. It appears (1) you want to provide a multiplicity of +5 V output signals, presumably each with sufficient current to drive "shielded reed relays" on a separate external board, (2) that the number of outputs be anywhere from ten (prototype) to several hundred (production?), and (3) the outputs to be controlled by statements written in C++ programming language. Surely, you suggest, such an interface should be readily available... somewhere.

    Are you planning to do "bit-banging" on individual relays? C++ has no provisions for "bit I/O" or, for that matter, any hardware-oriented I/O. All I/O in C++ is created in streams to or from "standard" I/O devices for which drivers have been written. The usual suspects for I/O are files on formatted disk drives, keyboards, CRT or LCD display devices, serial ports such as RS-232, RS-485 or USB, and (now obsolete) parallel printer ports (the so-called Centronix printer standard). All of these are very much dependent on operating system and hardware particulars, hence the need for "drivers" to interface to the C++ "standard" I/O devices.

    Here is a general-purpose I/O board that plugs into a PCI Express socket and provides 32 input and 32 output channels of digital I/O. Enjoy. (It's a bit pricey!)
     

    Attached Files:

    Last edited: Apr 23, 2015
  13. Dannybaws

    Dannybaws

    17
    1
    Apr 18, 2015
    Well appologies again for being unclear. I'm doing my best.

    I'm not looking to control from C++ directly. I am just looking for either of these two things:

    Preferably:

    A) A board which will send +5v signals to up to 10 outputs. I could then put a wire from these outputs into individual reed relays within individual devices. As stated above, they do not need to be perfectly in sync, but I would like a delay of under 1ms and no limits on how many can be used simultaneously. This board would take C++ commands to select which outputs are sending out voltages.

    Alternatively:
    B) A board similar to above but with the relays attached to it. Meaning my devices would need to have wires going in and out.

    Thanks for the suggestion of board, this is a suitable price for my needs. However I'm at work and it won't let me download the manual, so I'm not sure what it does :( will try again later.
     
  14. Dannybaws

    Dannybaws

    17
    1
    Apr 18, 2015
    Just had a look at manual, got it working. Looks good, however I do not really need inputs as there is no need for me to discover if something is on OR off. If there is a voltage applied to a NO relay, it will be closed for example. But at least I know roughly what I'm looking for now. Pretty sure this sort of thing should work for my needs.
     
  15. Dannybaws

    Dannybaws

    17
    1
    Apr 18, 2015
    Basically this:

    https://www.pc-control.co.uk/minibee_info.htm

    But
    on a more industrial scale rather than an entry-level hobbyist product (no offense to hobbiests I am also).

    Obviously preferably not USB and only 5-6v output needed and expandable into the 100s would be good, but this could potentially be done software-side.

    Currently chatting with a couple of electronics companies online so may find the answer and will post if I do.

    thanks
     
  16. Dannybaws

    Dannybaws

    17
    1
    Apr 18, 2015
    Sorry to keep posting on my own thread. Last time.

    The people at advantech recommended me the PCIE-1752, which is an output only module. But it just seems a little complex for the task need, I only really need TTL (+5v) switching, nothing more and it seems to do a lot of other fancy stuff.

    Will consider it, but will keep looking for now.
     
  17. hevans1944

    hevans1944 Hop - AC8NS

    3,989
    1,899
    Jun 21, 2012
    You consider this module fancy? Why? What does it do that you don't think you need it to do? Maybe you should draw up a design specification and contract to have your board made. Surely you aren't getting any "help" from anyone on this forum.
     
  18. Dannybaws

    Dannybaws

    17
    1
    Apr 18, 2015
    You've been a great help thanks.

    I'm not really sure, I think it's just because I don't really know exactly what I need. I'll keep looking into it and talking to the company that makes it to check it will meet my needs. I'll probably be paying an electronics dude at some point, just want to try make the first revision myself.

    Thanks everyone I'm a lot closer now to what I want.
     
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