openrcforums

I've used two receivers bound to the same number in a plane to make connections easier. For example, one in the wing and one in the fuselage so only a power connection between the two.

I was wondering if two RX6R receivers bound 1-8 telem (master) and 9-16 no telem (slave)connected via SBUS would give PWM channels 1-6 on the master, 9-12 on the slave and still be redundant?

Yes but only one way. If the "secondary" receiver that has its output connected to the other loses signal then its pins will go into failsafe.

Not sure if you can connect them both in a "ring", would need testing. Might be OK in theory.

So say I have the wing receiver (ail, flaps, gear, motors) as secondary, fuselage receiver (ele, rud, gear, steering, telemetry) as primary.

If the primary loses signal, I still have all those servos but my wing servos all go to failsafe? If the wing receiver loses signal, it's servos still go to failsafe?

Normally I would have separate ubec for the two receivers. Would the SBUS connection be a problem? Should those ubecs be diode isolated? Maybe go with a single ubec and battery backup?

No, if the primary loses signal then all servos continue working. If the secondary loses signal then wing servos go into failsafe while fuselage continues to work.

For the dual battery setup either the BECs should have diodes on their output, or you could remove the red wire from the SBUS connection and have both sides powered separately.
If you use diodes then you can have the power setup redundant, but make sure the red/black of the SBUS cable are capable of handling the current draw of the other side.

Would be worth wiring the SBUS ins and outs both ways to see what happens depending on what link fails.

Hello,
i asked question for FRSKY support and just received answer :

"If you want to use redundance function with R-X8Rpro receiver, you only connect the servo channels from RX8R receiver(master receiver).

When both receivers are working, the output signal is from the master receiver. when the master receiver lost the signal, the output signal of the master receiver will be obtained from the slave receiver."

so i suppose principle is same with RX6R.
in fact, i have same configuration as you describe at beginning of post : 1 RX8Rpro as master and 5 servos connected (channesl 1-6)
1 X8R as slave with 7 servos connected (channels 9-16).
all that works finely
BUT
if i enter into range check, i lose control of one of the two receivers (but leds of both are green) instantly
if i get of range check i recover control of all servos
if i renew enter into range check, i lose control of one of the two receivers, but not necessarily of the same receiver
...
etc
...
I'm waiting for anwer of FRSKY support on this point.

wait and see...

My own tests of this setup were glitchy. But I didn't spend too much time figuring out what the problem was. I was anxious to fly so I switched to a single X8R and a multiple connector to handle the 4 wing channels.

It does not appear that this set up will work as I had hoped. Thanks for investigating this.

had you tried range check in your last configuration ?

I did not. I had some intermittent aileron servo jitter that was fixed when I went to a single receiver so I didn't pursue the combination further.

I would like to know what is happening when you switch on or of range chek, regarding servos control

(Intermittent aileron servo jitter)
May be caused by having servo wires to close each other.
If servo wires are needed to be to close together,
then using shielded servo wires may be a help.

Probably not the problem in my case. The second receiver was replaced with a multiple connector that put the wires even closer together.