AutoMatch™
#11
(06-08-2021, 06:34 AM)XPS Wrote:
(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.

Okay thanks. It’s easy to get focused on direction and forget about PWM range. I never even looked at PWM range until I purchased an X24. It’s pretty cool knowing exactly where the servo position is.
Reply
#12
Thanks to XPS for the support and thoughtful, timely responses. Problem solved by using the S.Bus to program the slave (in this case) to "R" not the XPS 24. That is, when matching the master and slave were set to "N", and then no problems. Probably not relevant to many people except to those who are setting up dual servos on either side of a direct drive rudder where, in effect, the servos are rotating in opposite directions. This may be a quirk of the Futaba S9177SV servos and their interaction with the XPS 24 but nonetheless this is what worked.

best

B.
Reply
#13
Thanks for posting this information. We are looking into this since you should be able to reverse the slave servo and have it work the same as you reversing the servo in its programming.
Reply
#14
It’s my understanding that after an auto match the EPA of a group can only be reduced. Never increased. So if my elevator has way more travel than I need. Do I simply reduce the high and low EPA of the master servo in that group? Do I need to auto match again after reducing the EPA? Can dual rates be programmed in my transmitter like they normally would?
Reply
#15
AutoMatch needs to know the absolute maximum range of throw for your surface.  You can never change the EPA to increase that throw limit, but you can reduce it.  Any settings you use in the radio for rates does not matter.

The reason why you want the absolute most throw available is that during the AutoMatch a table of sub-1us servo positions is built based on the current consumption between the two servos while the matching occurs.  That table starts out empty.  The table has enough space to handle +/-150%.  If you only match for 100% and then find out that you need 4% more throw, you won't be able to simply change the EPA in the X24 because there would be no table data after the 100% that you started with!  This is why we always recommend that you set your surface deflections to a bit more than you will ever need because certain types of mixing could push you over the edge of where you thought your max throw would be.  We could have set a hard stop point, but we found that this was too restrictive for some cases.
Reply
#16
Okay that makes sense. So just reduce the EPA of the master servo if need be, and the slave will follow.
Reply
#17
Yes. The slave follows the master based on the match table that was built during the AutoMatch. If there is no match data (what happens if you increase EPA later on) then the slave has no idea where it should go.
Reply




Users browsing this thread: 1 Guest(s)