Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Radio Equipment => Topic started by: davidsg1a on April 13, 2010, 05:56:40 pm
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Hello gents, Iv bought the giant cod 2.4ghz 4 channel, iv have a problem wen i turn the hand set on the motor goes flying astern, the only way to stop it is to go back and fore on the controller and then its ok, so can anyone help me on how to stop this from happening before i hit someones boat.
David
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Sounds like the speed controller 'neutral point' is not set up correctly, what make and model is it?
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The speed controllers a viper marine 25, Iv tryd the speed controller set up and it seems to be in ok (might be me doing sumit wrong), when its up and running fine its just wen you turn everything on goes full astern and I have to go full astern on the stick and back to stop
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Are you turning the transmitter on before the receiver ?
You have to give the receiver and escape time to sort themselves out after the Tx is turned on, if you don't it does its own thing and you have to switch the receiver off and start again.
Been there, done that, bought the t shirt.
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Hello dickyd, I turn the receiver on first wait till the flashing lights on the speed controllers stoped and then turn on the transmitter, then a couple of seconds later it starts going hell for leather and then i have to go full astern on the stick then to stop to stop the motor. once iv done that it runs fine until i turn the transmitter off and turn it back on again it does the same thing.
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Hello dickyd, I turn the receiver on first wait till the flashing lights on the speed controllers stoped and then turn on the transmitter, then a couple of seconds later it starts going hell for leather and then i have to go full astern on the stick then to stop to stop the motor. once iv done that it runs fine until i turn the transmitter off and turn it back on again it does the same thing.
There is your problem! Always turn the Transmitter on first. check the throttle is at neutral, then turn on the receiver and allow things to settle down. Shutting down you turn off the receiver then the transmitter.
Mike
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davidsg1a
ALWAYS turn the transmitter on first.
This gives the speed controller and the receiver the signal as neutral without it looking for it and going full astern.
If you think about it the electronics require a signal.
With no transmitter signal they will either lock on to another stray signal or look for the transmitter signal.
That is why you ALWAYS turn on the transmitter first.
Bob
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Hey bob and mike, iv tryed doing it the way you both sugested and it still seems to be doing the same, i dont know if maybe its a prob with the hand set, >>:-(
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To ascertain if the problem is indeed your hand set, try plugging the speed controller into another channel on the receiver. Try also plugging a servo into any and/or all of the channels on the receiver and see if that works as it should. If the problem is still there, then it might be a case that your Viper is up the spout.
Good luck.
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PMK thank you very much that seem to do the trick changing the speed controller, and thanks to bob and mike I thought I was supposed to turn the receiver in the boat on first, {:-{
Thanks again guys
David
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Sometimes Viper ESC's do kick and need a few seconds to settle down.
Bob
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Hey guys same prob again, giant cod say the problem is because the unit is set up for air craft, it some sort of safety thing planes, he says there is away of sorting it but I have to contact a guy on there form but waiting for a reply at the moment, if any one else knows how to sort this give me a shout please.
David
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Hi David,
Are these the instructions you are using?
http://www.mtroniks.net/resources/ViperMarineInstructionManual_2.jpg (http://www.mtroniks.net/resources/ViperMarineInstructionManual_2.jpg)
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Hey martin,
Ye thats the instructions i have for the viper, but the speed controllers not the problem, wen I connect the speed controller to any of the other channels its fine, rob at giant cod says it's somthing to do with hand set been set up for planes, but there is a way of changing it he says just a case of finding someone who knows how to do it.
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OK...
1. plug in a servo to the receiver.
2. plug in a (good) battery to the receiver (4.5-6v and NOT the speed controller)
3. turn on the transmitter
... what does the servo do?
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Also, have you got the 25 quid GC set? They do two cheap ones - one at 25 which is a simple one, not optimised for any particular vehicle, and one at 52 which is specialised.
You can get the 52 pound one in two types, for fixed wing or helicopters. But if you have the 25 pound one, I do not think it makes sense to talk about aircraft setup.....
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Martin
When I do that the servo make a wee noise and then it works fine.
Dodgy geezer
Its the 25 quid 4 channel set iv got, I just cant work out wats going on.
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Right. :-))
4. Unplug (switch of) the receiver (Rx) battery.
5. Turn the servo arm/disk to one end, till it hits the stops
6. Turn on the Rx.
7. Turn on the Transmitter (Tx)
... what does the servo do?
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The 25 quid 4 channel has two switches inside on the circuit board.
One is the MODE switch, which should just alter which stick works which servo.
The other is the MIXER switch, which 'mixes' the output of two sticks, so one servo can be worked by two of the sticks. Some people have reported getting a set with this switch in the 'MIX' position, which can end up confusing people.
I wonder if this is what has happened? The MIX switch can be got at with a stick through a hole in the battery compartment. But wait till Martin has gone through basic testing with you before doing any fiddling.....
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Ok iv got the servo in the channel thats giving me probs now, so wat happens is wen I push the rudder over and turn on it stays hard over and then i wiggle the stick and it goes back to centre and if I leave the rudder mid ships and do the start up again it goes straight to hard over.
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dodgy geezer
I looked at that switch and it at normal.
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For reference, these are the switches that dodgy geezer reminded me about! :embarrassed:
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Ok iv got the servo in the channel thats giving me probs now, so wat happens is wen I push the rudder over and turn on it stays hard over and then i wiggle the stick and it goes back to centre and if I leave the rudder mid ships and do the start up again it goes straight to hard over.
Does it do that in the other channels to?
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sorry miss read your question, no the other channels are fine
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I think we have your answer!..... a faulty channel.
For testing purposes, try setting up the speed controller in another channel.
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It all works on the other channels, I tryd the mode switch and that moves the problem to the other side.
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Just got a message on the giant cod forum and the guy there says:
(The transmitter is set up to operate with aircraft. Throttle is either high or low depending where the stick is positioned ...there is no centre zero on the throttle stick. Your boat has reverse. Aircraft only use one direction for motor rotation).
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Well mine works fine without any "fixing" with Vipers.
I do file the ratchet to give a constant neutral and set up the viper to this.
Turn on Transmitter.
Turn on Viper Switch.
Press set button.
Go full ahead then back to neutral, the green led glows till neutral selected.
Same for astern.
Vipers do however have a car/aircraft setting which can be changed by:
Press set button and switch on.
Press set button 4 times.
Bob
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Which channel is it?
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Hey Bob, Iv try doing the things you have said and its still selecting astern when switching on.
Martin Its the third one down.
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My wife has a similar problem with her lifeboat.
Switch on Tx, switch on Rx and motor starts up flat out.
Turn of Rx then turn on again, wait a few seconds and it then works fine.
Weird. {:-{
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Ye think im gona have to bite the bullet and just put up with it, as long as I set it up and turn it all on before it goes in the water I'll get away with it. >:-o
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Try it out of the water first. :-))
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When the GC 2.4 TX is first turned on it applies throttle, before turning on the RX and setting up the ESC move the throttle to full power and then full reverse, then centre it. Turn on the RX and set up the ESC.
The GC can be easily improved for use with boats if you are happy to lose the warranty.
1. set the four recessed front dipswitches to mode 1 ie down.
2. remove the 4 screws from the backplate, no need to remove the battery cover , or batteries.
3. Open the case and set the small Mode dipswitch on the PCB to "Mode 2" and the mixer dipswitch to "Normal"
4. The throttle channel is fitted with a ratchet, undo the small screw and remove the sprung steel arm. Put these to one side.
5. If you are happy with a throttle that does not self-centre then go to 9 below.
6 On the right hand control identify the unused channel 2 ( up and down ) and you will see a plastic arm held in place by a spring. Move the gimbal as necessary and gently slide the arm off it's pivot. Use tweezers to remove the spring.
7. The plastic arm and spring fit onto the throttle mechanism on the side opposite where the ratchet was fitted, fitting the arm and spring is the reverse of removing it and the throttle now self-centres.
8. If you wish, fit the ratchet arm onto channnel 2 by slotting it into the groove and fix it with the screw. ( Everything so far is reversible if you need to make a warranty claim )
9. This TX applies full servo movement with only 3/4 TX control movement, this can be easily corrected by simply inserting 1k 1/4 watt resistors by following this guide (http://www.giantcod.co.uk/forum/viewtopic.php?f=15&t=2858&hilit=), there is no need to do the Rates mod.
10. close up the case and refit the 4 screws.
These changes make the Giant Cod 2.4 a much better radio for use with boats.
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dodgy geezer
I looked at that switch and it at normal.
Ok - just a thought.
There are a couple of other known issues with the cheap GC set.
1 - the quality control can be a little dodgy. On one of my sets I found that one of the wires to a stick pot was only held on with one wire strand. So it's worth checking these (particularly for the channel which is a problem) You may find that a poor connection is the cause of your problem.
2 - all of the channels on my cheap GC set did not make the servo give its full swing - there was 10% or so missing. This can be corrected by soldering a 1K (I think) resistor into the wiring line - see the GC forum for details of this. I wonder if that might have an effect....
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I think that a very good point dodgy , they are very cheap and cheerful but fantastic value for money - 2.4Ghz 4 channel radio for £25! :o
I suppose several mods are possible, thanks for yours kinmel, I might just move the pot or wire and swap the channel around internally
as I won't be using more than 3 channels, so I can sacrifice channel 3.
BTW, someone remind me please, which stick movements relate to which channel please?
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Martin if you are not using a channel you can screw a strap across the two green arrowed holesmake it out of plasticard and you may need to put a bit of packing under the middle remove the spring an arm first and use it for self centering somewhere else. any of the pots can be done as you will prob need that one
Peter
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Hey Martin, thanks for all the help, i'll try and help you now.
D-D is Channel 1
C-C is Channel 2
B-B is channel 3
A-A is Channel 4
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Thanks Peter, thanks David.
Thank you New York and good night.
oHico :-)
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Memo to the Da Man Upstairs:
"Dear Lordy, please can I have one of whatever Martin is drinking?"
This is a bloody interesting thread.
I don't actually own a GC radio myself, so if it's not too stupid a question, what would happen if he (davidsg1a) were to replace the trottle stick with a self-centreing type? Would that be all it takes in order for his Viper work as it should?
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PMK,
If peter likes the ratchet on the throttle stick (as I do).
Just remove the back 4 x screws and you will see the ratchet on the stick.
Set this control to neutral and mark the grooves on the side with a pencil.
Move the stick for this mark to clear the spring arm.
Rub a small triangular or square file on its edge along the plastic groove opposite the pencil mark.
Check that this gives the stick a noticeable neutral point. if it does replace the back.
This will allow you to set up every ESC on the same transmitter signal as the stick will be in the same place every time.
This does work as I have now done it on 4 transmitters.
Bob
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I hear what you're saying about filing that groove. Neat idea; perhaps ought to be the very first modification for any GC owner to consider.
So, if I'm on the right track, the general consensus seems to be, as long as the Viper receives a steady neutral at start-up, then everything will work as it should.
Thanks for the heads-up.
I wonder if it would be possible to squeeze a ready-made self-centering stick in there, such as one, say, from a Futaba set?
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I think that a very good point dodgy , they are very cheap and cheerful but fantastic value for money - 2.4Ghz 4 channel radio for £25! :o
Umm...no. As of a week or so ago they are 5 CHANNEL radios. See the GC forum for details of how to attach a switch to add another channel.
And watch that space for further developments - I suspect the basic transmitter is 6 channel, with two suppressed - work is progressing on unlocking the last channel...
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A friend has had problems this weekend with one of these sets.
Used on a sail winch he had problems trying to move the winch on the left stick sounds like the same problem to me.
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Are there any spares available for the Giant Cod 4 5 6?! channel radio system?
Maybe the self centring arm....
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No Mustang Mark made his own
Ned
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Are there any spares available for the Giant Cod 4 5 6?! channel radio system?
Maybe the self centring arm....
This is what the arm looks like. Sorry I can't post an exact size pdf - the board software won't allow it - PM me if you want the pdf file...
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Having tried, I find I can't post pdfs anywhere. Looks like I will need personal e-mails for anyone who wants a pdf :(( :((
Mind you, I have also realised that, with a slight alteration of the angle at the bottom of the arm, this would also make the throttle stick into a 'self-centering' 75/25 stick. Is that what people want - a stick which 'centres' to a neutral which is not perpendicular to the case front, but tilted towards the case bottom? This is what the arm would look like in that case...
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Having tried, I find I can't post pdfs anywhere. Looks like I will need personal e-mails for anyone who wants a pdf :(( :((
Mind you, I have also realised that, with a slight alteration of the angle at the bottom of the arm, this would also make the throttle stick into a 'self-centering' 75/25 stick. Is that what people want - a stick which 'centres' to a neutral which is not perpendicular to the case front, but tilted towards the case bottom? This is what the arm would look like in that case...
Some very old Futaba sets (medalion) where supplied with two spare arms one for self centering and one for 70/30
Peter
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:-)
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I'm pretty sure I know the reason for this problem. I suspect that the TX/RX are set up for helicopter use. With RC helis, the throttle channel is automatically set hard back on power up to prevent the rotor spinning up past takeoff speed. This is irrespective of the position of the stick. It is necessary for the flyer to actively move the stick to the fully down (idle) position to initialise the throttle before it will respond to changes.
Of course there is no reverse on a heli motor/engine, so mid-stick is actually half power. As you, presumably, have the stick set up as centre-off, then what is idle on a chopper is full astern to you (and your ESC)!
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I agree with nsa66, the system is set up for aircraft/heli use, with a failsafe at zero throttle on startup, as related to a forward only speed controller.
This obviously equates to full reverse with a forwrd/reverse type esc.
This is borne out by the return to 'normal action' after the first operation of the throttle stick on the Tx, with the stick at centre travel now being zero motor speed, relative to the esc setup..
This should be able to be checked, by now switching the Tx off, with the model in a safe location obviously, whilst the Rx is still on.
The system should then go into failsafe, as per aircraft mode, for a zero throttle setting. However in the boat application, with a Fwd/Rev esc, this will be full reverse.
The only solution would be to find out how to reprogramme the throttle channel on the Tx, to give normal Fwd/Rev about midstick position, and remove the failsafe function.
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Ive been following this thread with interest, particularly as on one of my boats, I too was getting the excessive throttle power at start up.
Reading the various issues, Im starting to wonder if a couple of other glitches I have had with different boats could also be connected to either the RX or the TX.
In each instance, the boat sails well for about 15 or 20 minutes, then loses forward power. Sometimes reverse works immediately, sometimes I have to wait a few seconds. Yet when I get to the shoreline and the boat is out of the water, forward motion works again. Back in the water and after about 20 yards it stalls again.
Of course first reaction is battery - but this I have ruled out as in each case its a 6v gell cell and the current drain is such that the boat should be able to run for several hours.
Second reaction is could the motor be faulty - have changed motors to a completely different type - same problem.
Third reaction is could the ESC be faulty - again changed to a totally different type - same problem.
I have also tried a second GC rx unit, with same results, all of which points to the transmitter glitching but where or what should I perhaps look into - it almosts seems to be an overheating issue perhaps ?
cheers
Andrew
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BlueWotsit ~
"Of course first reaction is battery - but this I have ruled out as in each case its a 6v gell cell and the current drain is such that the boat should be able to run for several hours."
Is your ESC specified to work on 6 volts? Some ESCs have an internal voltage regulator which is there to supply a steady +5 volts to the rest of the circuitry. If this is the case, then your ESC is probably designed to operate at roughly 8 volts minimum. Since you're using just six volts, means it could very likely be the cause of all those nasties you described.
"Second reaction is could the motor be faulty......"
It could - but I'll bet it's not. The motor is probably pulling n amount of amps when it going flat-out. This can put quite a voltage drop on the battery, which means that your 6-volt gel-cell is no longer pumping out 6 volts.... causing your ESC to complain even more.
"Third reaction is could the ESC be faulty - again changed to a totally different type - same problem."
By now you might be getting the idea that the ESC is maybe perfectly okay, but that it's designed to operate on a higher voltage.
"I have also tried a second GC rx unit, with same results, all of which points to the transmitter glitching but where or what should I perhaps look into - it almosts seems to be an overheating issue perhaps?"
You're right - it could be any (or all) of those things, but I'd suggest that you check to see if your particular ESC is indeed suitable for 6-volt operation first.
Good luck.
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BlueWotsit ~
"Of course first reaction is battery - but this I have ruled out as in each case its a 6v gell cell and the current drain is such that the boat should be able to run for several hours."
Is your ESC specified to work on 6 volts? Some ESCs have an internal voltage regulator which is there to supply a steady +5 volts to the rest of the circuitry. If this is the case, then your ESC is probably designed to operate at roughly 8 volts minimum. Since you're using just six volts, means it could very likely be the cause of all those nasties you described.
****Yes - its one of the Mtroniks range which have a wide variance in voltage capability
"Second reaction is could the motor be faulty......"
It could - but I'll bet it's not. The motor is probably pulling n amount of amps when it going flat-out. This can put quite a voltage drop on the battery, which means that your 6-volt gel-cell is no longer pumping out 6 volts.... causing your ESC to complain even more.
****The motor / battery combination had worked fine when used last summer with 27mhz - with small tug boats, and similar you dont have to be running at high speeds as that simply is not scale
"Third reaction is could the ESC be faulty - again changed to a totally different type - same problem."
By now you might be getting the idea that the ESC is maybe perfectly okay, but that it's designed to operate on a higher voltage.
***the change of speed controller to a different model Mtroniks again just a higher capacity one
"I have also tried a second GC rx unit, with same results, all of which points to the transmitter glitching but where or what should I perhaps look into - it almosts seems to be an overheating issue perhaps?"
You're right - it could be any (or all) of those things, but I'd suggest that you check to see if your particular ESC is indeed suitable for 6-volt operation first.
Good luck.
***thanks for the input - Im going to borrow a 27mhz setup over the next week having offloaded all of mine, as Im easy on the ESC situation seeing as how they had worked previously with the different TX / RX combo, also I had forgotten until I was looking this afternoon, that in one of my boats the Model Slipway Sentinel which had also experienced the problem which is actually powered by a 7.2v NIMH
Sail boats are so much easier !!!!!!!!!!
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I wish I had read this stuff two months ago. I helped my friend change two boats from 40MHz to 2.4GHz and we had the same problem … and it doesn’t half make you jump the first time it happens!
It looks like the same Tx - the Giantcod 2.4ghz 4-Channel Mode2 Transmitter – with the 7ch 2.4ghz Frsky receiver and Mtronics Marine 15 speed controller in both cases. We checked and changed round everything without solving the problem.
The only thing I could think is that the BEC supply means that both the ESC and Rx have to be powered up at the same time. I thought perhaps the ESC was wandering before the Rx had locked on to the Tx signal. (I guess I could have temporarily pulled the power pin from the BEC feed so I could use a separate Rx battery, but the workshop time ran out for the day and I never tried it.)
However, nsa66’s explanation seems much more likely (that the TX/RX are set up for helicopter use). davidsg1a said that Rob at Giant Cod suggested that the problem is fixable. Did he come back with any more details? Alternatively, has anyone else found out how to reprogramme the throttle channel on the Tx as Peter suggests?
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radio link 2.4 systems have a failsave on throttle switch it on to another channel using the mode switch on the back of the tx pcboard this will swap to mode 1 and should be ok
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Hi all, I'm a bit late to read this interesting problem.
Does anyone know if it is common to any other systems ?
I have a Spektrum DX6i with MR3000 receiver that does the same in my IOM yacht. Switch on tx, then rx, and the winch goes past the sail full out position before returning to a position corresponding to the throttle stick. I would not worry about this glitch but the sheet attachment smashed the tube that takes the winch line through the deck. It might be possible to adjust the sheet lengths and winch drum to move the attachment point, but I don't know how far the glitch would try to take it if it didn't reach the physical limit and stall.
The idea that it is a heli trick sounds plausible but my tx is converted to mode 2 and is programmed for aircraft not heli.
None of my other tx's do this (DX6 and DX7), nor my other systems (Hitec and Futaba) - they all go straight from the parked position to wherever the stick is.
When I have time I'll see if a servo in the throttle channel does a similar movement.
Jerry
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I know this is an old topic but Ii found this on Griant Cod... and I just went through this pain at the weekend. >:-o
I like the 'swap pot / channel' idea!
Re: Setting the failsafe on RadioLink 2.4ghz
Postby Phil_G on Wed Mar 24, 2010 9:08 pm
To explain, please for a minute imagine the Radiolink is installed in an electric plane, with a conventional ESC.
In common with Futaba radios, the Radiolink transmitter has a 'reversed' throttle channel with respect to the ESC input, and to operate an ESC conventionally, the 'reverse' switch must be set for the throttle channel. It does not have a failsafe. In the absence of a signal, the channel pulses from the receiver to the servos will cease. In a conventional ESC, this will cut the motor, so although its not specifically a 'failsafe', the result is a safe situation with the motor stopped.
The Radiolink transmitter expects to be controlling a unidirectional motor or engine, where motor speed is proportional to the amount of 'forward stick', and with low throttle (or throttle cut in the case of electrics) with the stick towards you. In a conventional setup therefore, the 'safe' position is with the throttle stick pulled fully back.
With this in mind, Radiolink added to their transmitter firmware a further safety feature, a 'throttle-lock'.
What this means is that if the tx is powered up with the throttle advanced (ie anywhere but fully back) then the throttle channel will transmit 'low throttle' until it is unlocked. To unlock, the throttle stick is pushed forward, then returned to the 'low' position.
Throughout the unlock process, the channel continues to send 'low throttle' pulses to the ESC. For high-powered electric planes this is a real boon for safety.
Now, with a bi-directional ESC, our safe 'low throttle' position is actually full reverse, and the neutral 'motor off' position is seen by the throttle-lock feature as a dangerous setting, which it over-rides with what it assumes to be 'low throttle' until you unlock it. This is why your motor is spinning up in reverse.
Two things you can do, one easy, one a bit more involved, but better.
The easy wasy is to switch on the tx first, pull the throttle right back, forward, then back again. It is now unlocked. Set it to mid-way and switch on the rx.
A better way would be to swap the wiring to the throttle pot with the wires from the elevator pot. This will put the throttle-lock feature on the elevator, which I assume is unused in your application. You will of course need to move the ESC to channel 2.
There is a third way which may work, I don't know as I've not tried it and my own Radiolink gear is long gone. Inside, in the centre of the board, is a switch labelled 'mode 1 or 2'. This switch might move the throttle-lock to channel 2. At least it is very easy to try. You may or may not need to switch the ESC from channel 3 to channel 2 again.
Hope this explains what's happening, and gives you an idea or two as to how to overcome it. If not just shout again.
Cheers
Phil.
http://www.giantshark.co.uk/forum/viewtopic.php?f=9&t=3734&st=0&sk=t&sd=a&hilit=radiolink+pot
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Two things you can do, one easy, one a bit more involved, but better.
The easy wasy is to switch on the tx first, pull the throttle right back, forward, then back again. It is now unlocked. Set it to mid-way and switch on the rx.
A better way would be to swap the wiring to the throttle pot with the wires from the elevator pot. This will put the throttle-lock feature on the elevator, which I assume is unused in your application. You will of course need to move the ESC to channel 2.
http://www.giantshark.co.uk/forum/viewtopic.php?f=9&t=3734&st=0&sk=t&sd=a&hilit=radiolink+pot
I have used the first approach for a long time now, and think that is better. The point about it is that it 'forces' you to positively turn on your Tx and operate it first, before turning on your Rx, which is a good habit to get into.....