ADF2 question

[HardRock]

I have a 2" sub-driver running an ADF-2 and a Lipo guard. I've just added an "X" tail mixer (high quality, un-named, unbranded, $10.00 at Hobbyking) and the system has gone nuts. When I remove the ADF-2 from the system everything works. With the ADF-2 plugged in, the ballast servo jitters at first, then pulses whilst the other servos jitter.

I'm assuming that I have the world's crappiest 'X' tail, but I wonder if there is a simple fix or if anyone knows of a good quality mixer that won't send the ADF-2 nuts.

[KevinMc]

This is a new one on me, and while I don't have another X-tail mixer to suggest I would like to better understand the problem. What other equipment is around the ADF2? (What receiver? What ESC?)

Does the ADF2's power on blink pattern change with and without the X-tail mixer plugged in? What pattern do you see?

I'm assuming that the X-tail mixer is taking the pitch output from the ADF2 and the rudder output directly from the receiver?

What happens if the X-tail mixer is plugged in to two other channels from the receiver? (It's not a useful configuration, but it adds a data point to understanding the problem.)

[HardRock]

The receiver is a Shultz Alpha 8 channel; the transmitter is a Robbe/Futaba 16. The ESC is a Viper 10. There is a Lipoguard between the blow servo and the ADF.

Without the X tail module connected, the system works fine. ADF finds neutral, green light goes on, pitch changes in the ADF output correctly to servos. The ADF activates blow servo when the receiver signal is lost.

With the x tail module connected the ADF led flashed green/red at about half second intervals, in time with the blow servo which pulses and the rear planes servo which glitches back and forth. With the ADF pitch control taken out the X tail mixer (and the ADF fail safe) work fine). Actually the mixer has a pretty choppy output. It seems like there are about 20 steps along the travel of each servo.

Just tried the system with the mixer plugged into channels 5 and 6. Same result - red/green flashing and pulsing blow servo, glitching planes servo.

[He Who Shall Not Be Named]

That Lipo-Guard has to be between the receiver and the ADF2's 'fail-safe' lead. Not as you currently have it.

M

[HardRock]

Thanks. Going back to the bunker to check if I have it backwards or just lack the ability to communicate effectively in English (my second language actually since I'm AUSTRALIAN).
Also, your goody box arrived here this afternoon. Thanks seems a less than adequate word. It was very generous of you and I appreciate it. That Alpha is going to look bloody good!

[HardRock]

If you can follow the spaghetti trail in this photograph it appears that I do, in fact, have it backwards.

[HardRock]

Duh! Reconnected the the thing the right way round and it works as advertised however the ADF is no longer detecting the loss of receiver signal. No red led flashing or solid and no command to blow the ballast tank. I've reset it a couple of time and it goes through the setup sequence correctly and appears to be working but once the transmitter is turned off nothing happens. Any chance that I've fried it?

[KevinMc]

Thanks for posting the photo, that really helps. (Yes, I can follow your spaghetti trail.)

First up is what David's already caught with respect to the order of signals in the ballast signal chain. (Thanks David!) You must have Rx ch 4 => LiPo Guard => ADF2 (failsafe) => Ballast servo.

The next thing I see which confuses me is your ADF2 pitch side signal chain. It looks like you've connected Rx ch 2 => X-tail => ADF2 (pitch) => Pitch servo. If you've got an X-tail boat you ought to be using Rx ch 2 => ADF2 (pitch) => X-tail => X-tail servo.

Now to jump back to what you've observed with the failsafe: Shutting down the radio doesn't trigger the ADF2's failsafe. I don't think you've fried anything, I think your receiver is activating its built-in failsafe; When you turn off your transmitter the receiver's failsafe instantly kicks in preventing the ADF2 from ever seeing a missing signal. This doesn't mean that you don't need the ADF2's failsafe in the chain as it's still needed for proper operation of the LiPo Guard when it detects that your batteries are flat, but ADF2 won't react to a lost transmitter signal because it will never see one. Can you turn the receiver failsafe off? (Or test the theory with a different receiver?) ADF2's failsafe gives you much more control over what your servos do when the signal is lost and it almost certainly waits for longer than your Rx before doing anything. All the receiver-based failsafes I've seen trip off after about a second of signal loss where ADF2 will hold for about 5 seconds before moving to the 1st failsafe position. If you're still running gas ballast this can make a big difference.

Last thought for now: Pay careful attention to the indicator LEDs on the ADF2 at power-up as they tell you everything about how the ADF2 is operating and what it thinks it's supposed to be doing. When you first power up the green and red LEDs should both come on for about a second, then you'll get either a 2- or 3-blink flash pattern. Check the manual for the codes and make sure the flashes are consistent with the connections you've got. For your setup you should be seeing G+R then either G-R-G or G-G-R. If you disconnect only the failsafe line the pattern should change to G+R, G-G. (The ADF2 is telling you that when it configured at startup there was only a pitch signal, no ballast signal.)

Read, digest, play, report back!

[HardRock]

Thanks for this. Back to the bunker to unscramble and reassemble. Wait, out.

[HardRock]

All good. Changed the receiver because the synthesised one that I was using did not allow me to override the inbuilt failsafe. The new receiver (which is actually to old and larger receiver that I swapped out because of its size) works just fine. ADF-2 works perfectly now that its connected the way it should be and even the el-cheapo X tail mixer is working according to the great plan. Amazing what happens when you follow the instructions!

I was almost at the stage of putting the boat in the water when there was a small farting noise and this happened.



This is the small tube between the restrictor and the valve in the gas system. The tube came of the fitting once before and it looks like it might have been damaged when I slid it back on. There is a small abrasion at the centre of the rupture which might have been the reason for the failure. There is a replacement in the 212 kit so I've fitted that this afternoon and I'm about to back to the water.

[He Who Shall Not Be Named]

Yet another reason to shy away from the gas type ballast system. Glad you got things working, HardRock!

M

[He Who Shall Not Be Named]

Yet another reason to shy away from the gas type ballast system. Glad you got things working, HardRock!

M

[vital.spark]

David,

Your gas ballast systems work great and there are less things to that can go wrong! You can even turn the boat upside down and it doesn't create a vacuum which could cause a marginal seal to leak! Huh Trout??? I have 4 of your gas systems and swear by them! David you went to the moon with your SAS but in my opinion unnecessary and more trouble prone and lack of emergancy blow!

Myron

Myron

[trout]

Myron,
Haven't turned my sub upside-down yet, but you are correct a strong jar or, as David mentioned, steep angle could cause it to unseat and the vacuum does put additional challenges on the seals (but once it is fixed, it seems to stay fixed - give it time to see). The gas system works very well, but it can have its own issues too. I like the gas, but dislike filling it or running out of gas. The SAS keeps running. Ideally having both systems, like Mark is putting in, is the blending of both worlds. I use both types and they both functionally work well. Although, if I was forced to pick only one, it would be the SAS because no gas.
Peace,
Tom

[KevinMc]

Well, preferred ballast system aside the root of the problem I see here is the ADF2's inability to detect singal loss from receivers that have an integrated failsafe. These were few-and-far-between when the ADF2 was designed but time marches on and they're now much more prevalent. That said (and without wanting to give too much away) I am working on some new solutions to restore the balance. Keep your watch-men on high alert...