Trainer function

[Galaxy]

Hallo to everyone.
This is my first post and first of all I'd like to thanks the developers for the eccellent works on the ER9x. The firmware is fantastic, the radio has functions that is difficult to find also in very expensive radio. Great work folks.

Coming on the topic, i'd like to connect two radios, the Turnigy with ER9x as master with graupner Mx16s as slave.
I've set the training On on Turnigy and I've set the Rudder on CH4 with replacement from trainer radio and with a %=100 and the switch set to ---.
Now, turnigy with power On and graupner with power OFF I've connect the two radios using a mono jack cable on DSC connector. But the CH4 don't respond to the input coming from the trainer radio (Mx16s).
The Mx16 funcion perfectly with a sinulator.

I've tried also to connect the Graupner as master and Turnigy as slave (Turnigy power Off Trainer Off and Graupner power on with the trainer function on THR switc). With THR switch off the Ch4 respond to the master stick, but when I switch the THR ON (CH4 from trainer radio) che chennel 4 doesn't respond to the stick position both on graupner and Turnigy.

Any idea? Could it be a problem of compatibility of PPM signal? I don't know for example... timing or voltage levels?

Thanks in advance.
All the best,
Mario

[gohsthb]

have you read through this page?
http://openrcforums.com/wiki/index.php/ ... ster/slave

-Gohst

[ShowMaster]

Ideas?
You only mention ch4. What about Tho, Ail, El, do they work?
If they do that maybe Ch 4 is in some other position than the first 4?
I Scope would help there.
If you've not done the 1K resistor ppm mod or removed the tx module that may help, does it?
Finally, the stock 9x wants 5 volt ppm trainer input as master. Many TXs put out 3volts or less and won't drive the 9x without a 1 transistor mod added.
The 9x should work as a trainer tx however.
So what's working and not. More details the better the answers will get.
SM

[Galaxy]

Good morning and thanks.
I forget to mention that the original rd module has been replaced with Frsky one. Do I need the 1k resistor ppm fix anyway?
Regarding the other channels, I don't try yet because I don're need it. But this evening I'll try.

Other important info is that when I try to use the Er9 as student, the rd module was removed.

Do you suggest the 1k mod?
Thanks,
Mario

[Kilrah]

From what I remember the MX16s is one of these transmitters that give a PPM signal with a ridiculously low voltage (about 1V) on the trainer port. Most transmitters won't take that as an input, I've had to make a buffer in the past for someone who wanted to use it as trainee with a Futaba radio.

[Galaxy]

From what I remember the MX16s is one of these transmitters that give a PPM signal with a ridiculously low voltage (about 1V) on the trainer port. Most transmitters won't take that as an input, I've had to make a buffer in the past for someone who wanted to use it as trainee with a Futaba radio.

Thanks, I tried to measure the signal level coming from the DSC connector connecting the cable to the radio, one time on the Turnigy and one time to the Graupner. I perform the measure using a multimeter setted to CC and using a mono jack cable with one end connected to the radio and the other one connected to the multimeter (not loaded). I know that this way is not correct because I measure only the "average value" but in any case the voltage was around 4 volt in both cases.

This evening I'll perform the measure using an oscilloscope. Do you think that the measurement should be made under load? In other word, must i connect the two radio by cable and then make the measure? The output of the DSC is open collector?

Thanks,
Mario

[Kilrah]

the voltage was around 4 volt in both cases.

That reminds me that the output on the mx16 is not only weak, it's AC-coupled. I.e. a nightmare, the master radio actually receives a signal that's below 0V

grt.png (3.25 KiB) Viewed 8228 times

The 9x puts out (and expects) a nice DC-coupled 5V signal.Lower amplitudes will work down to 2-3V or so which the mx16 doesn't even give, but that AC coupling is a killer.

9x.png (3.21 KiB) Viewed 8227 times

No way without a buffer.

[ReSt]

how about a pullup resistor that moves the DC level to 5 volt and a diode, with anode to the 9x.
If no signal is input, level is high and with signal the negative peaks pull it down to ground direction.
+5V
|
__
| | 4-10kohm
|
--||----->--------|<----+------> to 9X
Diode
K A


Reinhard

[MikeB]

The processor pin for the trainer in function is configured with a pullup resistor (20K-50K) internal to the processor. The problem will be that 1.5V signal level, it's far too low. Even with a diode, the signal will not pull down to 0V on the negative going edges. It might just be made to work if a pull down resistor is added, the value should be the same as the pull up resistor to bias the input to 2.5 volts, unfortunately the specification for the pullup is very wide. You could try fitting a 50K pot as a variable resistor, set it to about 30K and work up and down from there to see if it works.
This is another example where the original hardware design made a poor choice of processor pin. It would be most useful if the trainer input went to the analogue comparator (AIN1). This would have allowed the comparator to act as an amplifier. It would also have been better to use an output compare signal to drive the PPM out, there is one on PB7 and they didn't use that pin at all!

Mike.

[Galaxy]

Good morning.
I checked the signal caming out form Turnigy and Mx16s. As kilrah said, the signal of the Turnigy is about 5V while the MX16 is about 1.5v with capacitive coupling.
I tried also to connect the Mx16 as master and turnigy as slave and this configuration functions without problems.
At this point the options are two:
1-Make a buffer that allow the connection of the Mx16 as slave
2 buy another turnigy as slave.

I think that the most reliable option is the second one.

Thank to everyone,
Mario

[cxgiaco]

Hey All,
I'm in a similar boat as others, and have search literally for hours on how to go about hooking up the HK-T6A 6-channel hobbyking Tx as slave to my ER9x(no-heli) with smartieparts board (&backlight) and FRSKY DIY setup.
1) I have enabled "trainer mode" in er9x
2) I have adapted the HK-T6A to output ppm in standard 3.5mm jack
3) Both Txs work with the 3.5mm jack with the Almighty USB simulator
4) I do not see any ppm in recieved by the 9x Tx, and there is no response from the plane.

I am assuming that i do not need to do any voltage fixes, as the T6A works off 5v output, and i have the FRSKY module anyway.
Any ideas what i am missing here?

Thanks!
Giaco

[MikeB]

When you say you have enabled trainer mode in er9x, have you set up the trainer inputs in the trainer menu? (LEFT LONG followed by RIGHT)
When a student Tx is connected, you should see the inputs at the bottom of this screen.

Mike.

[cxgiaco]

Got it! Thanks for the help Mike! I had done the correct things, just not at the same time... I was expecting to see thehex readout showing the slave output, rather than just going to the graphical outputs screen. Turns out i didn't have the percentages turned up. In retrospect, the pairing for these two couldn't be easier, had i just known that....

[gohsthb]

I've updated the trainer section of the wiki.

http://openrcforums.com/wiki/index.php/ ... or/Student

-Gohst