Prewire question

[Berserker23]

When you prewire all the cakes on to the board and wire them on cobra slats when people say one side needs to be shunted what do they mean exactly i?m a little confused i?m using FireWire Initiators

[Rick_In_Tampa]

It's going to be my first year using Cobra slats too. Generally speaking, I know what shunting is as it relates to firewire initiators. However, in the context of using them with slats, I'm as lost as you are.

I ran a test of a few mods I converted to quick-plug cues along with the new quick-plug slats, and all the initiators fired. I didn't do anything special to the slat to "shunt it" either. So as far as I know, you don't need to add a shunt to the slat itself.

Having said that, I know there are series and parallel slats. One might require a shunt and the other may not. To be honest, I'd shoot Scott a quick e-mail and ask him.

If you do, please post his response here for the rest of us! :cool:

[jamisonlm3]

I'm curious about this too. I always assumed it had something to do wtih the way egniters are always shorted, but I think it's more than that. On some modules, there's a safe and fire switch. My guess is one is shunted and the other isn't. Looking forward to what you hear back Rick_In_Tampa.

[Rick_In_Tampa]

SO I did some digging and found a thread under the professional fireworks systems thread called "What are slats?" This is what a user posted back in June of 2018 regarding Cobra slats:

"So on your question about the shunts....if you get SERIES slats from Cobra, they come with a shunt...and yes you do need the shunt.
Cobra also sells PARALLEL slats which are designed to work with talon igniters and they do not need a shunt.

As far as the question about how many you can fire with 14.8 volts, if you go to the Cobra web site you can find the tables with all the firing capabilities of each power supply for both ematch and igniters. I would also recommend reading the tables on the MJG Initiators as they are different that ematch."

Now that I re-read that, it makes sense. However, I would still ping Scott at Cobra and get a definitive answer form him.

[Berserker23]

So I figured it out cobra covered it in their cobra classroom last week it’s on YouTube https://youtu.be/6g6ceY8wNjM talking about shunts starts at 53:14 it’s worth watching now I understand

[Rick_In_Tampa]

If you're using the new quick-plug slats there's a few videos out about them as well.

Here's one that covers the series version that says you need to use shunts:

https://www.youtube.com/watch?v=szDU03LVU3E

[rfgonzo]

You need to shunt each end of you slats so you don't get accidental discharge. Without shunts it's just like not having end wires twisted.

[rfgonzo]

You also need to shunt your last slat on a CH/bank when ready to fire or you won't complete the circuit.

[rer07]

Stupid question put do you have to use 2 shunts on either end of the slat when pre-wiring, or could you just loop a cable between the ends completing the circuit?

[rfgonzo]

Stupid question put do you have to use 2 shunts on either end of the slat when pre-wiring, or could you just loop a cable between the ends completing the circuit?

Not a stupid question at all. In theory I would think it would work but Iv'e never done it that way. I would call Cobra to find out for sure. I always just buy double the shunts when I order and use two.

[esgrillo]

When you are setting up your show you need to shunt series slats, not parallel. The shunt completes the circuit and needs to be on the last slat. Also if you are using several series slats in a row running if you have any cues that are not used you need to put a jumper in that cue to complete the circuit even if you are not putting a match in it.

This is pretty common for example if you are running 3 stations off one mod using slats you may not have effects on all 3 slats for each cue you fire. Like you make fire comets/mines on the outside 2 and then alternate to the middle. YOU NEED to put a jumper in each of those open cues AND the shunt in the last slat. This is for series slats only.

None of that is needed if you are using parallel slats that is the advantange of parallel slats and the advantage of series is you can fire more cues. Both have +/-'s

[esgrillo]

It's going to be my first year using Cobra slats too. Generally speaking, I know what shunting is as it relates to firewire initiators. However, in the context of using them with slats, I'm as lost as you are.

I ran a test of a few mods I converted to quick-plug cues along with the new quick-plug slats, and all the initiators fired. I didn't do anything special to the slat to "shunt it" either. So as far as I know, you don't need to add a shunt to the slat itself.

Having said that, I know there are series and parallel slats. One might require a shunt and the other may not. To be honest, I'd shoot Scott a quick e-mail and ask him.

If you do, please post his response here for the rest of us! :cool:

Rick you have parallel slats. Series slats come with a shunt and you will not get continuity let alone fire without thes shunt in.

[Rick_In_Tampa]

Rick you have parallel slats. Series slats come with a shunt and you will not get continuity let alone fire without thes shunt in.

Thanks Ed. I actually sped home when I got off work yesterday morning and went right to the garage to grab my box of slats to see what the heck I had. It's sad that you know more about what I have than I do, but I'm glad at least one of us has it straight! lol... Thanks buddy. :cool:

[AquaticPyro]

You cross the wires at first. I set up in my garage and shunted until I moved everything outside. The system was also powered off. Unshunt and then test on site.

[AquaticPyro]

Sounds like a safety feature. I just manually shunt my wires. Just unshunt while there is still daylight.

[Birdman]

As mentioned above, the shunt completes the circuit, as far as I understand it. Without the shunt on the last series slat it is essentially the same as not splicing the wire that runs from the last MJG back to the mod if you were splicing the MGJ's together in series and not using slats.

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