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Author Topic: Robbe Multi-prop Decoder question  (Read 4536 times)

Gunslinger

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Robbe Multi-prop Decoder question
« on: July 23, 2007, 12:33:45 pm »

I'm having some problems setting up the afore-mentioned device. I've got the 12+2 decoder which gives 2 x proportional outputs (standard servos) and 12 x switched outputs. The servo outputs are no problem at all - just plug the servo into the appropriate channel and away she goes (I'm using these 2 channels to control the rotation and elevation of a Fire Monitor). It's the switched channels that are giving me a headache and in particular switching the 12V Fire monitor pump on and off. Each of the output leads has 3 wires (which for a servo makes sense - positive/negative/control) but how do I use 3 wires to simply switch the battery in or am I missing the point here completely. The layouts supplied by Robbe are about as much use as a chocolate teapot!
Signed: A bit of a dunce at electrickery  :-[
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bogstandard

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Re: Robbe Multi-prop Decoder question
« Reply #1 on: July 23, 2007, 12:51:07 pm »

Hi Gunslinger,
You will find that these wires will only switch a very small current, and that depends on how many of the switches you use at any one time, so you have to work out how many lights, radar motors, horns etc. are being used and their total amperage. The instructions that came with the 12+2 decoder should tell you the total amperage that each port will take, plus the total amperage overall.
For switching larger currents you will require relay modules, the current from these small wires will switch the relay which in turn can switch a much larger amperage, like your water pump.
I have the Dusseldorf which told you all the required items in the instructions for build.
This has most probably confused you even further.

John
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Gunslinger

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Re: Robbe Multi-prop Decoder question
« Reply #2 on: July 23, 2007, 02:18:17 pm »


I have the Dusseldorf which told you all the required items in the instructions for build.
This has most probably confused you even further.


Mmmmmm... you're not wrong there :)  The reason I bought the 12+2 was that it said in the specs that it would handle 2 amps but I guess that's the TOTAL amps and also it didn't mention anything about having to use relays. The pump is an 12volt MFA and apart from a couple of flashing LEDs, that's all so do you think that that's going to overload the device. Also, my original question was what do I do with 3 wires?
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HS93 (RIP)

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Re: Robbe Multi-prop Decoder question
« Reply #3 on: July 23, 2007, 02:32:27 pm »

You may find the mfa pump draws more than that at start (with water in) I don't know that much about the unit but if it is powered outputs up to a total  2A then it would have no problem powering relays , these are  cheap these days but you would only have to use them on the items that req High power, just connect the coil to the unit and use the contacts as if it where a switch.

Peter
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bogstandard

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Re: Robbe Multi-prop Decoder question
« Reply #4 on: July 23, 2007, 03:41:43 pm »

Hi Gunslinger,
Sorry, forgot all about the three wire question.
The easy way is that the wires can control two circuits, one of them is a common wire, the middle one, and this is +. So you can connect one light to the middle cable and to one of the outside ones, you can also connect another light to the middle cable and to the other outside wire. So when you now push up on a switch, one light comes on, when you push down on the same switch the first light goes out and the second one comes on.
So on one switch you could have say all your running and nav lights on one side and the anchor light on the other side, so when running you put the switch up to turn on the nav lights, when you come to rest at the side of the lake, put the switch to the down position and this turns off the nav lights and turns on the anchor light. Or  if you are using the spring loaded both ways, a horn on one side and a siren on the other.
Hope that explains it a lot better.
Your water pump will most probably pull about 10 amps on first kick up so this would definitely require a relay module.
The Robbe numbers you should be looking at are:-

8303 - Relay module
8304 - Reversing relay module
8249 - Solid state control module for controlling a small motor fwd/rev (up to 1 amp)

I have included a scan of the basic circuits, as you can see, they have only used two wires, you can connect another circuit to the spare wire and the common centre connection.

John
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Gunslinger

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Re: Robbe Multi-prop Decoder question
« Reply #5 on: July 23, 2007, 04:14:56 pm »

Thanks, John - it all comes clear now  :) and those drawings are much clearer than the ones I have. I have taken your suggestion and ordered the appropriate Robbe relay so with any luck and a following wind we should be all lit up and spraying water everywhere by the weekend.  Many thanks for your help.

Paul
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bogstandard

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Re: Robbe Multi-prop Decoder question
« Reply #6 on: July 23, 2007, 05:41:40 pm »

Hi Paul,
What boat is it that you are using it on?
For the Dusseldorf I used the two rotary knobs to control the front monitor and the rear two monitors separately, and fitted two slide switches in the transmitter to give separate up/down for each set.
If you need to know any more about the set up don't be afraid of asking, I did it the hard way by trial and error, but by using just a little bit of thought you can use every switch on there, I even have a fully automatic anchor winch installed, that free drops the anchor and when winding in, switches off automatically when it is fully retracted, ready to be dropped again. So almost anything is possible, given enough money.

John
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Gunslinger

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Re: Robbe Multi-prop Decoder question
« Reply #7 on: July 24, 2007, 10:00:53 am »

Hi there John,
I've been a bit naughty really, it started life as a Trent Lifeboat kit but due to a couple of errors on my part (first time I'd done a GRP and Styrene boat, always worked in wood) plus my desire to make my boat a bit "different" it's not quite a "standard" Trent. As you can gather it's got a fully functional fire monitor at the bows and I've added emergency (blue) strobes and functional trim tabs etc. Still looks like a Trent (apart from the monitor) but obviously I couldn't use one of the standard names of boats in service so I've just called it EXPERIMENTAL. The more complicated I can make a build, the better I like it but unfortunately my electrical/electronic sometimes lets me down, hence the questions about the decoder but I feel confident now that I can get the pump working OK and then move on to the other bits and pieces.
BTW Having just 1 monitor, I've used the 2 rotary knobs for traverse and elevation so I've got 6 more switches to play with  :)
Also coming from electric flight, I'm heavily into hi-power Nicads/NiMh and LIPO batteries so instead of buying new Gel batteries for the boat, I used what I had. 'm using one of my LIPO batteries to drive the pump so it will have no trouble coping with the 10amp startup. In all, there are 6 batteries in the boat for the various functions but the waterline still came out spot on which was very gratifying, I've just got to make sure that the seals on the various hatches are watertight now.
Next project is a Krick Alexandra with a full steam setup (all the bits from ACS).

Cheers

Paul
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