2.4 issues with gear sequencers??
 

Hey guys -

I'm having a frustrating time trying to get a Jetronics gear sequencer working with my Spektrum 2.4 system (10X with Spektrum TX module, AR9100 RX, running on 5 cell NIMH packs) in my JL L39. Only the gear servo moves on command, but throw adjustments, etc. are not working (I swapped gear and door servos, problems follow the sequencer outputs). Might be a bad sequencer (Todd at Dreamworks was nice enough to last-minute-overnight one to me today), but might be an problem with the new 2.4 radios...here's why I say this...

My first choice for a sequencer was the JMP unit. I tried to order one from Tom, but he said to hold off as he was having issues with 2.4 radios - that Futaba FASST did not work at all and Spektrum compatibility was intermittent (some worked, some didn't - no way to tell which based on model #, date of manufacture, etc). I also spoke to a buddy using a Minihobby sequencer, and he also was having issues with 2.4. In troubleshooting the Jetronics unit, I then called Todd to discuss ordering a new JT unit and he mentioned that he is also seeing/hearing of compatibility problems with 2.4 radios.

I may have a bad sequencer - as soon as work is over I'll test the Jetronics unit on the bench with 72Mhz receiver and post results - but curious if anyone has run into this. [&o]

Barry

RE: 2.4 issues with gear sequencers??
 

Googled and found that this issue is not unique to me! I just ordered a couple of signal buffers/amps from ElectroDynamics to see if that helps solve the problem... see here : http://electrodynam.com/rc/conn/index.shtml#buff

Barry

RE: 2.4 issues with gear sequencers??
 

Hey Barry, just put a matchbox in between the sequencer and the receiver. Your problems will be solved.

RE: 2.4 issues with gear sequencers??
 

Barry, Had this problem with the 14 channel Futaba. E mailed Jettronics who did some tests and found the signal voltages were not high enough. I am waiting for a signal amplifier from Jettronics which should solve the problem until a solution is made with the sequencers and valves. But it does beg the question: why was the signal voltages lowered on the new 2.4 receivers.

RE: 2.4 issues with gear sequencers??
 

Futaba MZs have in and out timing mixing no need for door sequencers, I have set up a couple of jets for my friends
I think the FGs have it too
I know one of the issues with the sequencers is not having enough signal end travel adjustment

RE: 2.4 issues with gear sequencers??
 

Because these systems are implemented on state-of-the-art ICs. These days, nothing current runs at 5V any more and even 3.3V is getting used less frequently. Some high-end processors run as low as 1.2V or even 0.8V internally. With lower core voltages, it get expensive, in terms of chip area, to bump the I/O back up to 3.3V much less 5V. A cheaper solution is to have the other stuff run at lower voltages. All of the Futaba servos are OK with the 2.7V signal levels. Most of the JR and HiTech servos seem to be OK too. Some of the other stuff like sequencers and electronic valves are lagging behind...

Bob

RE: 2.4 issues with gear sequencers??
 

i just put a jet tronics in my cougar and using a DX-7 and had no issues.

the only issue was i had an air leak, but nothing to do with the sequencer.

RE: 2.4 issues with gear sequencers??
 

Darn it John...why didn't I think of that??? That's why you get the big bucks (does that mean I should get the girls?) :)

That worked, and the sequencer is now programmed and working...but get this... just for grins I removed the MB and tried it again, it's still working! I hate anything borderline or intermittent so the MB stays for now.

It would be nice to have the ability to create mixes or linked channels with programmable delays right in the radio...maybe JR will listen to us jet and/or scale guys for the next generation of radios....

Barry

RE: 2.4 issues with gear sequencers??
 

so....what exactly is a matchbox doing which allows the sequencer to work? anyone know if it'll have the same effect on the JMP unit?

RE: 2.4 issues with gear sequencers??
 

As Bob K said, it's a problem with the signal voltage swing on newer receivers. It is an IC technology issue, it is not manufacturer specific.

The servo outputs are pulse trains whose width varies to command different servo positions. Typically the voltage swings from 0V to some higher voltage that historically was close to the battery supply voltage. With newer ICs, this range can be much less .. from 0V "logic 0" to a high that is less than 3V for "logic 1".

If the device plugged into a servo output is expecting something like low being 0V and high being 5V, the designer might have set the threshold at 2.5V .. anything lower is considered a "0" and anything higher a "1". The idea here is that the signal voltage is not the key parameter, it's the pulse width. The actual voltage does not matter so long as it goes over and under the threshold.

With the newer RX's, I suspect that for some non-servo devices, and some older servos, the high output is not getting over the threshold of the servos or other programmable devices. So they see only "0" .. no pulses at all.

The reason the matchbox solution works is that it has a lower threshold to separate "0" from "1" on its input, and it then puts out a signal with a much larger "high" voltage. I suspect that the radio mfgs saw this coming years ago and reset their 0/1 thresholds much lower, and folks who make devices to plug in used older, traditional thresholds .. and as has been stated they will eventually make the adjustments (which fortunately is trivial for them to do).

I have seen the same behavior with the ECU on my Wren SS. I was not able to program it with the Fut 6014 RX, but once programmed in the same setup with an older 72MHz RX, it did respond properly to the throttle stick on the 6014. I must admit that even with a reasonable amount of insight into how the equipment works, this one baffled me .. interesting to see a report of similar behavior with a valve. Must be a reason... but makes you wonder if it would be flaky..

I wrote to Wren to ask their opinion, and they wrote back right away, but I don't think they understood the question .. I resent and clarified and I assume they will think about it (and maybe talk to Gaspar) and get back to me. For now, the idea of a signal buffer inline sounds very sensible!

Dave

RE: 2.4 issues with gear sequencers??
 

I had a problem with my electronic brake valve getting it to reprogram after I switched over to 2.4. I am not sure of what king it is.
It is the tall black plastic one with the set button on the side. It looks a little like the Orbit. I went to thier Web site and down loaded thier instruction and now it workes perfectly. Here is the link and programing steps.
Link:http://www.orbitronic.de/
Programming:
The Orbit PRO-Single-Action-Valve can be operated either in switching mode for cylinders
with return spring (e.g. Eurokit, Spring-Air) or in a proportional mode for air pressure brakes.
To toggle between these modes, hold the SET-button pressed while turning on the R/C
system. The status LED confirms the successful switchover.
● Pressing the SET-button for 1-2 seconds teaches the valve OFF (2: => 3:).
The status LED confirms this by flashing.
● Pressing the SET-button for more than 5 seconds teaches the valve ON (1: => 2:).
The status LED confirms this by flashing.
● Now the valve should follow the control input from the R/C transmitter.
Switching mode: The status LED shows valve ON (retract landing gear) or valve
OFF (extend landing gear).
Proportional mode: The valve pulses proportionally to the control input from 0 % to
100 %. Pressing the SET-button for 3 seconds stores the current R/C position (e.g.
elevator) as valve OFF OFFSET. The status LED confirms this by flashing. This
allows the input range to be spread to the best braking effect.

RE: 2.4 issues with gear sequencers??
 

Jet Model Products is addressing this issue. JR 2.4 and Futaba 2.4 radios are being tested right now. Last time I spoke to Tom he said parts should be headed to him by middle of March to fix 2.4 issue.

RE: 2.4 issues with gear sequencers??
 

This is the best explanation I have seen written. Very simple.

RE: 2.4 issues with gear sequencers??
 

RE: 2.4 issues with gear sequencers??
 

FYI, the Wren team reached back to Gaspar on the quesiton of the WREN FADEC ECU with the newer receivers. As usual, they went the extra mile to get a good answer to a customer question. With their agreement, I'm posting what came back from Wren via Gaspar:
Here it is:

*****************************
Hello David,

We've been talking to Gaspar, and he says the ECU is fine: see below.
He's obvioulsy following the discussion on RCUniverse.

Regards
Sara


Don't worry, there isn't any potential problem with the ecus, they
work with signals as low as 1V. There are some servos, sequencers and
powerboxes that have a very "simple" RX input that don't work with
signals under 2,5V, thus giving issues, and this is what is being
discussed now on RCU.

Gaspar

****************************

RE: 2.4 issues with gear sequencers??
 

More information on sequencers

I have been talking with Arno at Orbit and he says his sequencers work with a signal voltage down to 2v. I have ordered one for my new model and wanted to be sure it would work with the Futaba 2.4 Rx.

John

RE: 2.4 issues with gear sequencers??
 

using just a matchbox will solve the problem or you need to add a battery in it??

anybody try to use a gear safe from Tamjets.. between the sequencer and the receiver???

Heraldo

RE: 2.4 issues with gear sequencers??
 

EDDIEGIGOWATTS


Can you explain how to program the 14MZ, so don't need to use gear door sequencer???

RE: 2.4 issues with gear sequencers??
 

I have programed the Multiplex and also the JR9303 to do the door and retract cycling. It is really not all that hard, just takes a bit of thinking. On the Multiplex it is very easy and when I got my new 9303 I did not want to add a gear door cycler so it took a few hours but I have it working great.

John

RE: 2.4 issues with gear sequencers??
 

Guys,

Horst from JetTronics will have a solution for his valves and sequencer in about a week's time. It's a pulse amplifier and should cost around 6EUR to 10EUR

Here is the mail I originally received....

Hello Mark,

excuse the delay, I was in vacation and could receive but not answer
my mails.

I know about the Problem and have made a pulse amplifier for the
sequencer which is also good for all servos and other equipment like power
boxes and so on. I have myself 5 receivers and do not operate the most
important servos like elevator, ailerons, ruder, flaps and throttle without
this pulse amplifier even the servos work on the test bench, they can fail due
to temperature or supply voltage changes during flight, because
everything is right on the edge with this small pulse amplitude.
So I really recommend to use an amplifier, even the servo works.
Please read also this link: http://forum.robbe.com/viewtopic.php?
t=389

If you use the sequencer with amplifier you will not have to have
amplifiers for the valves. I have not checked the valves directly on the
receiver yet.

Best regards
Horst

As I am running my valves into a sequencer and then into my PowerBox Royal I won't be affected but those with JetTronics valves straight into the RX should get one of these amplifiers .

Rgds,
Mark

RE: 2.4 issues with gear sequencers??
 

FYI
Jet Model Products has done a software/hardware update to JMP sequencer in now works with 2.4. Tom should have stock of new units by end of this coming week.

RE: 2.4 issues with gear sequencers??
 

why learn the hard way??[8D]

just get a powerbox!;)

Mark i love my Royal too!!:D

RE: 2.4 issues with gear sequencers??
 

Glad to hear that JMP has been very pro-active in coming up with a design revision/update to support the new generation of 2.4 Rx's.

On a related note - JMP called me yesterday to tell me they had a fix and had set aside two of the new sequencers for me. (Tom, I'll speak for both - one for me and one for Buck Garza). It is rare that you get this degree of customer care and support - Tom had obviously saved my Email from a month or so ago and took the time to personally call me. Thanks! :D

Barry

RE: 2.4 issues with gear sequencers??
 

Hello Guys,

i need some help and input about this problem. i have a JL F15 fitted with a Futaba 2.4 R6014FS Rx connected to a Powerbox professional and powered by 2 - 5 cell 6 volt batteries(3800Mah each). My gears are driven by a dual valve jetronic, another one for the doors and a single valve for my brakes. The whole Aircraft used to be a 72Mhz set-up, but since I replaced it with the 2.4, everytime I turn ON the Batteries All My Servos starts to flutter, they moved uncontrollably( no problems with My Jetronic valves as I dont notice any switching on those three).
I did some trouble shooting: First I removed the Powerbox and replaced it with a Powerbox sensor(battery backer) and it works fine, Would this set-up be good and safe enough for the Jet?
And then I also replaced the 2.4Ghz Rx with My old 72mhz set-up and it was as normal as before. The problem with using a 72mhz in My Part of the world is that It is never controlled, there is no controlling body and sometimes people just turn On their Radios w/o clearing the freq., so basically its not safe.

Could this problem of Mine be the same as the one you are discussing?

I hope somebody can help on this. Thanks and happy flying.

Cheers,
Juaffy

RE: 2.4 issues with gear sequencers??
 

Juaffy
You should take a look at this thread.
http://www.rcuniverse.com/forum/m_7243983/tm.htm
Futaba's 2.4 R6014FS RX has a lower signal voltage output and its causing some problems.