Protocol specific equivalent of sub-trim"

Hi.

Is there an a .INI file somewhere that adjust the values sent to the RF module for the mid point settings? By mid-point, I mean: centered, calibrated sticks, centered trim, and centered sub trim settings in the firmware mixer.

Here is the situation behind the question:

I have a new Devo7E, loaded it Devination 5.0, and bound it to a couple of my Spectrum DSMX model's. After calibrating the sticks on the 7E, Everything was was spot-on. Only slight trimming was necessary relative to the same model controlled by a Spectrum transmitter.

I also bought a WLToys V911 RTF heli (with the WLToys transmitter), and flew it on the stock TX for a while. Out of the box, the heli needed a few clicks of AIL and ELV trim achieve hover with little drift. Overall, not much trim adjustment was needed.

Then I harvested the A7105 RF module from the WLToys transmitter and installed it in my Devo 7E. The hardware install went smoothly, and I enabled the A7105 in the modules.ini file. I then added a new model (for the V911) in the 7E, selected Flysky protocol, and bound the heli. I also reversed the servos in my 7E as needed. So far, so good.

Problem:
With the Devo7E in now in control of the V911, the servos (on the heli) have jumped to a new center point. (Not totally unexpected.) However, the difference was so large that no amount of subtrim could compensate for it. I had to remove the servo horn from the servos and reseat them at a new angle just to get the heli flyable. I'm worried that I'm close to the physical limit of the servos.

I understand it is a complex system.

• The Tx hardware measures the resistance of the potentiometer in the gymbal.
  
• The measurements are sent on to the mixers in the firmware.
  
• Mixers outputs data to the Protocol sections of the firmware.
  
• Then protocol sends values to the RF module.
  
• The RF modules sends a radio signal the the receiver.
  
• The receiver sends a PWM value to the servo,
  
• And the servo finally rotates to a particular angle.

LOTs of components in the path from stick position to servo angle. Each has a limited dynamic range.

So is there such a thing as a standard values for mid-points ? Does WLToys build in some biases into their Tx/Rx/servo combination that the Devo7E/Devination5.0 does not ? I'm using the same V911 heli (the Rx and servos) and the exact same RF module (A7105). The only difference is the transmitter hardware (Devo7E) and firmware (Devination 5.0, & Flysky protocol)

And like I said earlier, using the 7E, with stock CYRF6936 RF module, over DSMX, required very little trim adjustments. So I don't think the problem is the 7E hardware or the mixer sections of the firmware. The issue seems to be to be either:

• An offset in Dev5.0's Flysky protocol, or
  
• Dev5.0's Flysky protocol is just fine and, relative to other FLYSKY models... WL Toys V911 TX has a large offset on AIL&ELV channels, (but not on THR & RUD) and they compensate for it in inside the RX of the V911.

I'm wondering if I can easily add a protocol-specific offset between mixer output and the RF module inputs. The goal is any new Flysky/V911 models will be trimmed very close to their factory TX's behavior.

I guess I would need channel specific offsets (AIL/ELV), since the throttle and rudder on the V911 seem to behave just fine.

Thank you for your time and attention to this puzzle.

Also, if this issue belongs under a different forum category, please let me know. I will move it to the correct spot.

By the way, I did notice there is the concept of: Protocol_Options. Example:

[protocol_opts]
WLToys ext.=V9x9

However, looking at the UserManual, none of the Flysky->WLToys choices seemed appropriate for the V911

Texacate wrote: However, looking at the UserManual, none of the Flysky->WLToys choices seemed appropriate for the V911

Correct. The WLToys extensions are about their use of high bits in the primary control channels for secondary functions - turning the LED's on and off, flips, stuff like that. The V911 doesn't have any such features, so none of them apply.

Can't help with the protocol-specific trim issues. AFAIK, we've never had a report of something like that before. The V911 in particular has been very popular for quite a while. I've had enough of them I've forgotten the count, and never run into this problem. This makes me think something else might be going on, but have no clue as to what it might be. Do you have another FlySky Rx or Tx you can check things against?

Thanks for the reply.

Yes it absolutely could be something wth this particular heli and/or its RTF-Tx.

Unfortunately I don't have any other models on hand to try. I just got my Devo7E last week along with a V911 RTF. Virtually of my RC stuff is DSM2/DSMX, and so far they have all ported over seamlessly. I do have another V911 on order from Bangood (just heli w/o TX), and a 4in1 too. I was too excited to hack the 7E, so I pilfered the RF from the WLToys TX... We'll see what happens when my stuff gets here.

I did splice a header into wiring on the A7105 module, so I could quickly move the RF back and forth between the Devo7E and the WLToysTX.

Was wondering if, in general, different flavors/brands of A7105 RF modules could make any difference to the basics neutral settings of the channels. Doesn't seem like that is possible, since (I assume) the signal is all-digital by the time it gets to the inputs of the RF modules.

And I fully agree, the V911 is not new. Its been around few several years now. So it's probably something else. Will keep debugging if it continues to be an issue.

I'm very grateful to the developers. One transmitter to rule them all!

Well, I started over from scratch with a blank modle.ini and things are fine now. I have no idea how I got it so mangled earlier. Chalk it up to not knowing what I was doing.

If the moderator wants to deleted this entire thread, I'm fine with that. I don't think there is any useful info for anyone else...