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This thread is to discuss the AutoMatch™ feature - the most precision multi-servo matching system in the industry!
Here is a video showing how the AutoMatch™ works.



Hi - a repost from the flying giants forum below -apologies for the duplication but it might be worth revisiting. I noted your earlier reply to the FG post. The slave servo is reversed because there is an unusual geometry where the arms are opposed. That is, on the inboard servo the arm is outboard, and on the outboard servo the arm is inboard. It's a JTEC kit and that's the way the builder did it. In practice, going through the protocol the slave servo reversed means that both arms move in the correct direction with the stick (aileron) input. So, I tried again this morning as below with great attention to detail about pulling servos in and out as described. When I hit the match button, instant overload cut out, but not before the outboard servos was twisted in the mount. Advice very much appreciated since I'm really stuck now. Please see detail below.

best wishes.

B

Hi all - if I could have some advice regarding the servo matching I would really appreciate it.

My set up is XPS 24, Tx is Futaba 18sz, servos Futaba S9177SV SBus 2. I am an experienced builder/flyer but reasonably new Futaba person and brand new with XPS (previously powerbox). The servos have soft start active and failsafe hold. I can't seem to disable the servo failsafe hold from the TX (plugging directly into the servo port on the back), and have the servo programming dongle on order.

Dual wing servos (3M Extra) are in a slightly unusual configuration - inboard and outboard servos have arms opposed - in practice inboard (designated master) has "normal" direction and outboard (designated slave) needs to be reversed. Overall geometry is great - turnbuckle lengths identical at neutral etc etc.

So I read the manual carefully, noting the recommended procedure for matching servos where those servos have an active "hold" failsafe (not sure whether active soft start makes a difference). The results have been terrible (see below) no doubt due to my ignorance of the architecture/principles of the XPS 24 so advice appreciated! (Help!)

I have done the following EXACTLY.

1. Servo assigned to output port B1 Channel 6 (AILE2) for the Master
2. Servo assigned to output port B2 Channel OFF for the slave
3. Enter Automatch mode - no servos connected.
4. Choose Servo Group (2)
5. Entered Setup Master
5. Selected port B1, centered aileron, direction "N"
6. Unplugged master servo from port B1
7. exited setup Master, entered setup Slave
8. Plugged slave servo (outboard) into port B2
9. Port B2 servo enabled, direction "R", surface centered
10. Slave servo disconnected from port
11. Exit slave setup enter start automatch
12. Master into port B1, endpoints established by moving sticks, then left at center
13. slave servo connected to port B2
14. Automatch initiated...... servos screaming... overload triggered ... red light!

Afterwards the portB2 was completely inactive which I fixed by performing a reset.

So... I have also tried this by having the slave set to "N" not "R" within the automatch routine and the result was not as dramatic - an attempt at matching but after 30 seconds of noise, servos screaming (but no overload) and aileron deflected at around 5 degrees and there it stayed for a minute or two and with no further action I pulled the plug! Nothing at all like the videos I have seen using XPS 24 automatch.

I am certain I must be making some basic error so any inputs gratefully received. I have discontinued playing with the settings right now - I'm lucky that the servos pots still seem intact!

Thank you!!
You should probably not ever be using the slave servo output port as reversed. The slave should follow the master if the rotation direction is the same. That will always be the case unless you are two servos that were programmed to rotate the opposite directions on movement. So, if you reversed the master, you would NOT reverse the slave since it automatically follows the master. The option for reversing the slave is very specific and only there for certain cases.

The key here (because you have servos that go to failsafe without a signal) is to make sure that you are not trying to drive the servo at anytime without a signal, which puts it into failsafe mode (and holds it's position). If you follow the directions in the manual for using a servo that has failsafe (like Hitec), then this should work fine. We are only guessing that the reversed slave is a problem, and at some point you are plugging in the slave too soon before starting the automatch - or you are not allowing the match process to go long enough since it does take many minutes to complete. It's more likely the servos are fighting though because one is in failsafe mode.
What if the situation is a rudder setup with two servos in the tail. One servo is on the opposite side of the fuse. One servo pushes while the other one pulls. Would the slave be reversed?
(06-07-2021, 01:19 PM)XPS Wrote: [ -> ]You should probably not ever be using the slave servo output port as reversed.  The slave should follow the master if the rotation direction is the same.  That will always be the case unless you are two servos that were programmed to rotate the opposite directions on movement.  So, if you reversed the master, you would NOT reverse the slave since it automatically follows the master.  The option for reversing the slave is very specific and only there for certain cases.

The key here (because you have servos that go to failsafe without a signal) is to make sure that you are not trying to drive the servo at anytime without a signal, which puts it into failsafe mode (and holds it's position).  If you follow the directions in the manual for using a servo that has failsafe (like Hitec), then this should work fine.  We are only guessing that the reversed slave is a problem, and at some point you are plugging in the slave too soon before starting the automatch - or you are not allowing the match process to go long enough since it does take many minutes to complete.  It's more likely the servos are fighting though because one is in failsafe mode.
OK thank you, will give it another try and report back.

best

B.
(06-07-2021, 08:07 PM)A.Delaney Wrote: [ -> ]What if the situation is a rudder setup with two servos in the tail. One servo is on the opposite side of the fuse. One servo pushes while the other one pulls. Would the slave be reversed?

Only if the servo pulses are moving the opposite direction.  So, if one servo has a PWM range that moves clockwise from 900us to 2200uis and the other moves counter-clockwise with the same 900us to 2200us range.
I tried again as suggested but unfortunately not successful. Automatch initiated then after about 10 -15 seconds of matching (could see active current reading) the screen reverted to the Automatch menu and th process stopped. repeated. Same result. I have made a short vidoe showing exactly what I have done but it's rather large. Please indicate via pm, email or here where I can upload for your view. I will upload to dropbox and send link.

Thank you!

best

B.
Attach it to Dropbox.

It sounds like one of the servos (most likely the slave) is not getting a signal and is being locked into failsafe mode.
Thank you - link sent to tech@xtremepowersystems.net

best

B.
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