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E-stop with remote feedback

Discussion in 'Special Effects' started by SanTai, Jul 31, 2018.

  1. SanTai

    SanTai Active Member

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    Hi!

    I am looking for a e-stop with remote feedback.

    Scenario, we have several shots of confetti from in front of the stage. I want the crew to gave an e-stop that they only release when it is safe to fire. So far very easy and no problems. However it works be nice with feedback that everything is ready that is not dependable on radio communication. My first idea was a 4 pole e stop with the one pair for control of the gear and the other pair for lightning a small light by the controller indicating everything is ready. I have not found any 4 pole mushroom buttons though. Anyone know of a nice solution for indicating status of an e stop that is not under load?
     
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  2. soundman

    soundman Well-Known Member

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    I think I can help with this but I need a little clarification.

    Do you want to only be able to fire with the buttons are being held? or do you want several buttons around the effects that if any one of them is pushed, the button will latch and the system will not fire?
     
  3. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @SanTai I'm going back more than twenty years to a time when I was head electrician building the first AC servo automation systems on Broadway at a time when everyone else was still doing DC servo drives. Everybody else was using Allen-Bradley push buttons but we were using a European line and loving them. The line we were using were totally modular. I want to say the company was Sprecher and Shuh (Spelling?) They offered mushroom headed E-stops in two diameters, illuminated and non, and they could be any number of poles from one to as many as you wanted to bolt on to the actuator. Doing four poles of normally open or normally closed or any combination was no trouble whatsoever in latching or momentary. They even had a line of pneumatic time delay modules that kept the TUV inspectors happy in Germany. Not only were they fully modular and with every option covered but their pricing was better than Allen Bradley and they had great stock, support and delivery in Canada.
    EDIT 1: Here's a link to Sprecher Shuh's push buttons and pilot lights which may be of help. I suspect Sprecher Shuh is available to you in Sweden.
    http://www.sprecherschuh.net/pilot_...MIzbrR3tDJ3AIVT7jACh2fmAB_EAAYASADEgJ-3vD_BwE
    EDIT 2: Corrected spelling of Allen Bradley.
    EDIT 3: All of their buttons, rotary switches, and indicators mounted in ROUND holes, even their square buttons and indicators mounted in round holes. This is a serious plus when you're a small shop in the world of 'perpetual prototypes'.
    EDIT 4: They had an accessory which allowed padlocks to be fitted to lock-out their buttons, they had a line with keyed activation, including removable in one, both, or any of three positions but the pad-lockable accessory allowed you to use locks you already owned and for which staff already had keys.
    EDIT 5: @SanTai Maximum number of poles is limited only by the available depth of space behind your mounting panel. Contact modules bolt on to the rear of any / all of the various actuator modules. Contact modules may be one or two next to each other by as many modules deep as you have space to accommodate. Additional modules may be added at any time.
    EDIT 6: Added an omitted word.
    Did I mention I REALLY grew to like their line of buttons, rotary switches, indicators and contactors? [And their sales staff were always pleasant and helpful to deal with. A lady named Sherrie was my best contact.]
    Toodleoo!
    Ron Hebbard
     
    Last edited: Aug 1, 2018
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  4. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    I call this an enable station or button, and usually set it up with a momentary contact so the tech or spotter has to be depressing the button. If it requires pushing to prevent - like an e-stop - then if the spotter is not there it will go. Pretty sure you can find a momentary switch with two normally open and two normally closed contacts - so red light normal and green when enabled?
     
    Last edited: Jul 31, 2018
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  5. porkchop

    porkchop Well-Known Member

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    Normally for this I would do a standard 22mm base with a NO and a NC terminal block attached with a twist to release red (or yellow if you have other e-stops that aren't controlling the same system) mushroom head operator. Schneider Electric, Siemens, Omron, and many others make these types of build your own switch/button systems and they can be really nice to have around for things like this, but you pay for that convenience. The cheapest one I would consider using is $50 on Grainger. If you're looking for a cheaper, dedicated option I would buy this Honeywell switch from Arrow. Cross reference the part number in the datasheet and you will see it's 4 terminal with one NO contact and one NC contact.
     
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  6. danTt

    danTt Well-Known Member

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    This also sounds like a better application/usage of a "dead mans switch" to me. It's better to fail safe.
     
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  7. bobgaggle

    bobgaggle Well-Known Member

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    Second this. We dropped a queen sized mattress from 12' with a solenoid rig using a dead man. It was just a momentary switch wired in series to the hot wire. The rig was triggered from the board, but would only fire if the tech in the wings was pressing the dead man.

    On a side note, Im sure someone on here has seen this too, but I ran across a pit lift (not sure of the maker) where the deadman was a spring loaded 3 position rocker switch mounted to the handle of the wired remote control. you had to hold the switch in the second (middle) position for the lift to go up or down. The reason I heard was that if something goes wrong, some people tense up and some people just let everything go. This switch made sure the lift would stop no matter the reaction of the operator... pretty cool.
     
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  8. SanTai

    SanTai Active Member

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    Thank you for all the answers will Sprecher Shuh and the other suggested suppliers.

    It is good that several of you also recommends a dead mans switch, but that is not suitable for what I want to do. This is for locally disarming parts of the system before working on it to not be dependable on someone else not making mistakes. This is one of five keys/deadman buttons that has to be enabled before the fire button works in one of our common setups.
     
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  9. bobgaggle

    bobgaggle Well-Known Member

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    Seems like you got what you wanted from this thread, but maybe a lockout/tagout protocol would be in order if the whole purpose is to disable the machine for service...
     
  10. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    I don't think "deadman" which implies a hold to run nor "enable" are correct terms. You really just have switches in series that all have to be closed to operate. I would hope that one of these remote switches would not fire the device if all others happened to be closed.
     
  11. icewolf08

    icewolf08 CBMod CB Mods

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    If you want to do this without a PLC, you are probably looking at relay logic. I think the simplest thing to do would be to create a simple 24v "estop loop." This would literally be a 24v loop that runs throught all your e-stop buttons such that if any one is pressed, the loop is broken. You terminate the loop in a relay that opens and closes the firing circuit. When the estop loop is closed, the relay closes and the firing loop is available. If any of the mushrooms are pressed, the estop loop is broken, the relay opens, and you cannot complete the firing circuit.

    Depending on how safe you want it to be, you could involve PLCs and safety rated relays, redundant loops, and a way to issue a reset request other than just releasing the mushroom. All depends on your needs and the budget.

    Of course, the simplest, and safest solution would be for your staff to just remove power from the firing circuit and remove the propellant source locally at the machine they are working on before working on it. Then if the system is e4nergized for any reason, their local unit has been removed from the system. This could easily be accomplished with a simple disconnect installed at each unit, ideally a disconnect that support LOTO.
     
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  12. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Alex offers good advice on this. My take on the setup was
    which seemed to be an audience endangerment issue. Some kid looking into the canon. That's why I thought of manned enable switches. If its to protect staff when servicing the device, there are other suitable means. Its hard to know what the risks are without knowing the details.
     
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  13. SanTai

    SanTai Active Member

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    No I don't. It is the correct term because the firing system (please note that I am not using a light board for control) do not allow firings if the deadmans button is not pressed.

    This is what I want and what we are doing (except LOTO since the units are not physically large enough for that to make sense). I would just like to have remote feedback that everything is "turned on" again. It is the remote feedback I am missing. Still seems like the simplest solution would be to put a 4 pole switch instead of a common 2 pole(Control signal at the unit is mains voltage) to be able to have a constant 230V power feed to power a "feedback lamp". Basically 2 switches in 1.
     
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  14. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    I have to disagree. Deadman is associated with a person being at the switch and their absence should prevent the operation. Take your foot or finger off, and the device becomes inactive. It has to be pressed and constantly held, like a train throttle or gas pedal in a car, among many examples. I think you are using a machine-stop or e-stop switch/device and using wnat is normally the inactive position - in and locked down - in order to activate the firing of the device. An e-stop deactivates something when struck. You make it active when struck.
     
  15. SanTai

    SanTai Active Member

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    Still agree on the term and definition. Still using a deadman.

    What I was asking for in my first question was not a deadman and is not intended to be, used as one, replace one or be used to make sure everything is safe for audience and artist.

    For any safety critical device it is common to use both. For Pyro one of these are often called Arm key and is required in US to be an actual key if I remember correctly. The arm key is not a dead mans switch but is required to fire anything and generally puts the system in a more dangerous state, such as powers on modules or charges caps etc.
     
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