Gyro gain with Futaba T18MZ question

[Pedro]

All,

I have been studying my new T18MZ tx last week and I am stumped about one thing.

When I choose menu Gyro and set the AVCS gain to (for example) 30%, back out of that menu and switch to the servo monitor, it indicates that the output on the gain channel is 36%. Does anybody know why that is ? If I ask for 30% I expect to get 30% .

Whatever I input as gyro gain, it shows significant different on the servo monitor.

I can fix this by going into the ATV-End-point menu and change the end points for the gain channel from 100% to 85%. Now the set AVCS gain is exactly what is shown on the servo monitor display.

Is this the way it is supposed to be ? or should I ask Futuba service ?

Thanks,
-Peter-

[Nutter]

Peter

No. Your 18MZ is absolutely fine! Keep the ATV's at 100%. It doesn't matter what the figure is in the servo monitor as long as the gain on the 18MZ matches the gain on your gyro. I've just checked mine and the figure on the servo monitor is different to the actual gain in the gyro menu, but the gain set on my 18MZ is identical to the gain figure on my CGY-750's.

[Planehazza]

My 8FG does this also, it must be a way it works it out.

[Ludal77]

Maybe it's due to some EXP or D/R on this channel ?

[Mark_T]

If I ask for 30% I expect to get 30% .

30% of what though is the question?

The gyro just cares about the pulse width the radio is sending so if it takes 100% in the gyro menu to send 2020us to the gyro, but the servo monitor displays that as 120% it really doesn't matter.

This is one of those things that Futaba and Spektrum do differently.

[Pedro]

Thanks to all for the input. I am glad to know it is not a malfunctioning in the 18MZ but by design.
I have read through all the responses and they are valuable insights. For example :

@Nutter : If you can set a gain on a Futaba gyro than that might very well be an important factor.
I am using Align gyros and there is no gain on the gyro itself (just servo models, reverse, limit and delay).
@Ludal77: no, this is on a clean "model" with no dual rates or exponential. I use the "clean model" also to calibrate Phoenix flight sim.
@Mark_T: I agree that you set the gyro gain by looking at the tail authority and setting it higher or lower as needed. Who cares what is on the servo monitor ?

Thanks chaps !