DX9: What does Channel Assignment do?

[CaptHal8HS]

Hey All;
Just curious what this RX Channel Assignment is all about.
Can anyone do a better explanation?
Thanks.

[aerocal]

It does just what it says. It shows which channel from the processor is being output on each Rx port. If for example you have a model with Thr Ele and Ail but no Rudder and you want to use an Aux ch you could assign the Aux ch to Rud(Ch4) and use a 4 ch Rx. This is known as remapping channel outputs.

If you use Next from Rx Port assignment you get to Input Config menu. Here you can assign what the Input for each of the channels is. Example is switches,Knob,Levers,trimmers etc.

If N/A is listed it cant be adjusted. That means that it is controlled by the processor.

[CaptHal8HS]

Ah! Got it. Thanks!
Are most of the channel numbers standardized? For example, is throttle typically channel 1?

[aerocal]

Well you notice that the switches are now labeled A-H. We have finally let go of the legacy positions of switch labeling. Channel and Rx port labeling hasnt got there yet.
I wouldnt say "standardized". They are still identified by their legacy positions for the most part. With the ability to remap the port locations and Inputs it really doesnt matter what channel is where. When you start using some of the more advanced wingtypes you will see on Monitor that legacy positions can quickly get jumbled.
With Spektrum the big reason to always use Ch1 for Thr is that regardless of the available failsafe type on other channels the failsafe for CH1 always uses Preset on all Rxs. This is absolutely mandatory on Thr. You dont want to accidentally use it on a channel that uses Hold Last Position during a failsafe event.
Some Rxs have the ability to use Preset failsafe positions on all channels by using alternate Bind method. In this case it would be ok to have Thr on a different channel as long as it failsafes to Preset and forces Thr to Off if theres a loss of connection.

[flightengr]

For Spektrum systems, the normal order is:

Channel 1 = Throttle
Channel 2 = Aileron
Channel 3 = Elevator
Channel 4 = Rudder
Channel 5 = Gear
Channel 6 = Aux1 (Pitch on a heli model)
Channel 7 = Aux 2, and so on

Other manufacturers change up the first four.
So another good use for channel assignment is when you're connecting to a multi-rotor flight controller using a serial bus connection instead of individual wires for each channel. Depending on the protocol the controller is made for, it may expect a different manufacturer's design (Futaba and S.Bus, for example), which means it expects a different order for the channels.

A third use for channel assignment is common with the Apprentice S airplane receiver. It uses Gear for flight mode selection and Aux 1 for panic, and yet it has an open Aux2 port for flaps or another add-on. However, the built-in flap mixing on the Spektrum controllers assumes your flaps are on Aux1. Without getting into too much detail, this channel assignment feature lets you swap Aux1 and Aux2 around such that you can set up flaps using Aux1 as the controller expects and panic on Aux2, but then exchange Aux1 and Aux2 on the way out of the transmitter so the receiver sees the correct signals on the correct channels.

So this can turn out to be a really handy feature of a DX9. It creates an excellent new level of flexibility.

[CaptHal8HS]

Ok. I think I understand. You're just telling the radio to output a given channel/function on to a different receiver channel. Correct?

[flightengr]

Yes!

I believe this feature is limited to the DX9 and up. It's not on the DX6 or DX7, don't know about the new DX8.

[aerocal]

Channel Assign and Input Config are in fact a feature on all G2/G3 radios from DX6 all the way up.

[skyrotor]

Originally Posted by flightengr

For Spektrum systems, the normal order is:

Channel 1 = Throttle
Channel 2 = Aileron
Channel 3 = Elevator
Channel 4 = Rudder
Channel 5 = Gear
Channel 6 = Aux1 (Pitch on a heli model)
Channel 7 = Aux 2, and so on

Other manufacturers change up the first four.
So another good use for channel assignment is when you're connecting to a multi-rotor flight controller using a serial bus connection instead of individual wires for each channel. Depending on the protocol the controller is made for, it may expect a different manufacturer's design (Futaba and S.Bus, for example), which means it expects a different order for the channels.

A third use for channel assignment is common with the Apprentice S airplane receiver. It uses Gear for flight mode selection and Aux 1 for panic, and yet it has an open Aux2 port for flaps or another add-on. However, the built-in flap mixing on the Spektrum controllers assumes your flaps are on Aux1. Without getting into too much detail, this channel assignment feature lets you swap Aux1 and Aux2 around such that you can set up flaps using Aux1 as the controller expects and panic on Aux2, but then exchange Aux1 and Aux2 on the way out of the transmitter so the receiver sees the correct signals on the correct channels.

So this can turn out to be a really handy feature of a DX9. It creates an excellent new level of flexibility.

With respect to the normal channel assignment, Channel 1 is Throttle.

I'm setting up a AR7210 on a DX9. On the ports on AR7210, it has a labeled port for Throttle, then Channels 1,2,3,4. The AR7210 manual says to connect cyclic servos in port (channels) 1,2,3, then rudder on port (channel) 4.

Normal channel assignment on the DX9 shows Channel 1 as Throttle. Does this mean I need to go into DX9 menu and change Channel 1 to Elevator? Which channel does Throttle go to then?

Please help.
Thank you.

[aerocal]

Originally Posted by skyrotor

With respect to the normal channel assignment, Channel 1 is Throttle.

I'm setting up a AR7210 on a DX9. On the ports on AR7210, it has a labeled port for Throttle, then Channels 1,2,3,4. The AR7210 manual says to connect cyclic servos in port (channels) 1,2,3, then rudder on port (channel) 4.

Normal channel assignment on the DX9 shows Channel 1 as Throttle. Does this mean I need to go into DX9 menu and change Channel 1 to Elevator? Which channel does Throttle go to then?

Please help.
Thank you.

No. Leave the default channel assignments in the Tx alone and Swashtype of Normal-1 servo. The Rx processes them and then outputs them from 1-4 based on internal Rx settings. Look at the Rx manual to see what to plug into 1-4 on the Rx based on Swash setting in the Rx. The numbers on the Rx really have no connection to the channel order of the Tx.

[skyrotor]

Thanks for your help aerocal. I wish Spektrum and BX specifies that in their manuals. I'm sure it has confused other beginners also. RX and TX channels should mirror each other.

[flightengr]

While I'm all for documentation, you have to understand that the AR7200/7210BX units are a lot more than just receivers - they're full flybarless heli controllers. There are no set rules for which port on an FBL controller goes to which servo - that's up the people that write the software and you need to follow their instructions. So when I put an AR7210BX on a heli recently, I didn't even try to assume that the markings on the unit were channel numbers. The FBL controller would need to tell you which servos to plug in where based on your swashplate geometry. For the AX7210BX, that's the picture on page 5 of the manual for the cyclic servos and the tail is CH4.

If that really threw you off, then you might appreciate these setup videos. They're for the AR7200 but I still found them quite useful as the functions still apply on the AR7210.

AR7200BX How To Complete Initial Setup Guide (19 min 48 sec)

AR7200BX Parameter Menu Setup Guide With Governor Settings (16 min 18 sec)

[RookieAv8r]

I am using a DX9 radio with a JR 12 channel rx on my scale heli, and I have noticed that the aileron output on the rx is coming on the channel marked elevator and elevator output is coming from the channel marked aileron. I have made no changes in the radio as far as channel mappings. Everything works properly if I switch the aileron and elevator servo leads at the rx, but I'm wondering if it is a glitch, it may come back to bite me if it suddenly goes back to working according to the markings. Is this something normal between Spektrum radios and JR receivers.