Redundancy Receiver setup

[heliperry]

Ok I need help,
I'm having a brain fart. I'm setting up my Imac Plane with redundant receivers one is a RX8R bound with telemetry and the other is a full range XM+ receiver bound to the same receiver no. as the RX8R but with telemetry off .
I'm running 2 batteries and using a redundancy bus 10.
I'm trying to under that if I unplug the RX8R receiver from the redundancy bus 10 shouldn't the XM+ still allow me stick controls being it is a backup receiver? If so can someone help me with figuring out what I'm doing wrong.
Thanks.

 

[Nigel]

I believe you are talking about the functionality of a redundant power supply - redundant receivers only function to act as a backup in the case of RF loss, not power loss. You would need a FrSky redundancy Bus (RB-10 or higher), or another system that can manage multiple power supplies to provide redundant and filtered power.

 

[heliperry]

Hi Nigel,
I am using a Redundancy bus -10.

 

[Nigel]

Ah, so you have them both hooked up to the RB-10 and when you remove one receiver from power you don't have control? Did you double-check the channels you bound to for the XM+? (1-8, 9-16)

 

[heliperry]

Yes this is correct. I have bound the XM+ (1-8) as the same for the RX8R.

 

[heliperry]

The XM+ shows that it still is receiving power when I unplug the RX8R.

 

[heliperry]

I think I figured it out. I remove the XM+ receiver and bound another RX8R receiver with the other one and All Works when I unplug one or the other.

 

[Flying Dutchman]

So why did it not work with the XM+? And aren't you supposed to use Ch.1-8 on one Rx, and 9-16 on the other?

I have not done a redundant Rx setup yet, but I'm about to hook up (in ACCESS) a GR8 and an M+.

 

[heliperry]

I'm not sure why it did work with another XR8R receiver. That is something I will have to find out because I'm not sure what the XM+ is good for if it won't work! And as for the 9-16 channel I'm not sure why you would do that if your only using 1-8.
If anyone can explain this I'm listening.

 

[Flying Dutchman]

I need some help with a simple redundant Rx setup on gliders and other fixed wing applications. I have a few GR8's running ACCESS (they run great) to which I want to add redundancy using an Archer M+, also on ACCESS. I understand that I can just connect them with an extension cable using the S-Bus OUT, Gnd and V-IN ports. However, I don't understand what to do with the S.Port, if anything. The manual only tells you how to select it, but says nothing about what it's for or how to use it. On other sites I've read about using the S/F.Port for telemetry, but they are all drone-centric, talking about FC's and other stuff I don't know/care about.

My questions are:
1. If I just hook it up as above, will I still have telemetry when the main Rx (GR8) loses connection? (I do want this)
2. If the above setup does not provide continuous telemetry, is there a simple way to get it? (S.Port?)
3. What can the S.Port be used for in fixed wing planes, and how to do it? (if it's only for drones, I'll ignore it from now on)
4. Any additional hints or recommendations regarding redundancy setup? (e.g. channel ranges to select on either Rx)
Thanks!

 

[heliperry]

Hi Flying Dutchman,
These are all good questions. I'm still in the learning stages als. Some on that was helping me is https://forum.alofthobbies.com/index.php?members/scott-page.7/
If you can contact him I'm sure he will be able to help you.

 

[Flying Dutchman]

Yeah, I was hoping one of the Aloft guys like Chris or Nigel would reply, before I go bug Scott. I'll first let them enjoy their weekend.

BTW, I don't really know whether the Ch.1-8 vs. 9-16 issue is relevant to your situation; I have seen it being discussed here in the past, but possibly in a totally different context. Based on my limited insight, I thought that you can't have 2 Rx's drive the same channels. Perhaps it's different when you use an RB unit as a hub, vs. connecting the Rx's directly to each other.

 

[gnichola]

@Flying Dutchman I am not understanding your setup. You would connect the S-Bus out on the m+ to the S-Bus in on the GR8. I tested a setup like this, and I did get at least some telemetry as the signal strength was coming back to me. I didn't check to see what other telemetry I could get. My other question I have with your setup is why use an M+? It is a single antenna rx and it seems like the RS would be a better choice. I looked on the FrSky site and they label them both as "full range" however the M+ says "> 1.2Km" whereas the RS says ">2Km", so I am not sure what they mean by "full range"

 

[Flying Dutchman]

@Flying Dutchman I am not understanding your setup. You would connect the S-Bus out on the m+ to the S-Bus in on the GR8. I tested a setup like this, and I did get at least some telemetry as the signal strength was coming back to me. I didn't check to see what other telemetry I could get. My other question I have with your setup is why use an M+? It is a single antenna rx and it seems like the RS would be a better choice. I looked on the FrSky site and they label them both as "full range" however the M+ says "> 1.2Km" whereas the RS says ">2Km", so I am not sure what they mean by "full range"

I planned to connect them via S-Bus, as you suggest, but I'm just not clear what functionality that provides. Hence my curiosity about the S.Port.

The telemetry I get out of the GR8 (and want to retain with redundancy) are the Vario and LiPo voltage signals; I already assumed that RSSI would continue thru the M+.

I picked the M+ as it seemed to have more than sufficient range (I only fly LOS, well under 1km) and it's small. Also, I need to shove it down a long and narrow glider fuse (e.g. Prelude), which seems doable with the small single antenna M+, not so easy with anything bigger and dual antenna's.

In your setup, did you select Ch.1-8 on both Rx's, or split them between 1-8 and 9-16?

 

[gnichola]

Basically when you have a redundant receiver plugged into the primary receiver via S-Bus, the primary receiver then monitors the signal coming from both primary and secondary receiver. If/when the signal from the primary goes low, it fails over to the signal from the redundant receiver. Though I didn't specifically try it, I can't imagine why the telemetry would stop coming.
Both receivers are paired and I used channels 1-8 on both.

 

[Wayne]

I need some help with a simple redundant Rx setup on gliders and other fixed wing applications. I have a few GR8's running ACCESS (they run great) to which I want to add redundancy using an Archer M+, also on ACCESS. I understand that I can just connect them with an extension cable using the S-Bus OUT, Gnd and V-IN ports. However, I don't understand what to do with the S.Port, if anything. The manual only tells you how to select it, but says nothing about what it's for or how to use it. On other sites I've read about using the S/F.Port for telemetry, but they are all drone-centric, talking about FC's and other stuff I don't know/care about.

My questions are:
1. If I just hook it up as above, will I still have telemetry when the main Rx (GR8) loses connection? (I do want this)
2. If the above setup does not provide continuous telemetry, is there a simple way to get it? (S.Port?)
3. What can the S.Port be used for in fixed wing planes, and how to do it? (if it's only for drones, I'll ignore it from now on)
4. Any additional hints or recommendations regarding redundancy setup? (e.g. channel ranges to select on either Rx)
Thanks!

I'll attempt to answer, but this is not based on experience, so I may be wrong.. Some testing should confirm.

1- With ACCESS, yes I think you will still have telemetry. ACCESS is able to receive telemetry streams from 2 or 3 bound receivers at the same time (Not so with ACCST). So even if the GR8 is not being used for for RF, it should still be sending telemetry, and as long as the transmitter is getting that stream you will be good.

2- Should be good - I do not know if the GR8 can share it's data to the M+. My guess is not.

3- S.port is mostly for connecting sensors to your receiver. GPS, Vario, voltage, fuel flow, etc.

That should do you..?

 

[Flying Dutchman]

@Wayne: thanks for your response. Based on your input and from an RCG thread of a few months ago I was able to hook up the GR8 and M+.

In short, this is what I did:
1. Soldered the 4-pin header onto the M+. In the future I may skip the pins and solder a cable directly onto it.
2. Used the S.Port instead of S-Bus: since it is the 3rd pin, I could just plug a regular (24" braided) extension cable onto it. The S-Bus pin is #4, which would have been a pain to connect to. The minimal S/F.Port descriptions suggested that S.Port would work.
3. Used the converter cable supplied with the GR8 to connect the other end of the extension cable to the GR8. Also added a LiPo voltage lead to the white 4-pin connector on the GR8 so I have AIN2 telemetry.
4. In 'Options' for both Rx's left telemetry ON. Also left the (default?) F.Port2 boxes checked.
5. Mounted the M+ in the tail of my (HK ASW-28) glider, with the antenna outside and pointing up.

It all works fine on the bench, but I'll know more after test flying it tomorrow under actual conditions. I tried to simulate a GR8 connection loss by wrapping it in foil, but that made little difference in RSSI and VFR. Turning telemetry off in either Rx does not kill it, so apparently this setup provides the redundancy I wanted. Not sure how to best test distance performance of the M+ but hopefully log data will shed some light on that.

 

[Wayne]

Ahh, you would need the Sbus out from the XM+ to connect to the Sbus in on the GR8. Don't think you have a choice on this connection.

Simple way to test would be to bind XM+ to one model memory, and the GR8 to a different model memory. Then just switch between the 2 models. (Make sure you have different model memory numbers when binding.) Or if you have an extra transmitter you can actually bind 1 receiver to the other transmitter. After testing make sure you rebind so both receivers are on the same radio and the same model memory ID.

 

[Flying Dutchman]

Update on the GR8 & M+ combination: I flew it today and it worked flawlessly. BTW, I'm using the latest (2.1.7) FW on both. With the GR8 by itself, and with other Rx's, I'm used to getting telemetry warnings and occasionally 'lost' alerts whenever I get near 1000 ft, but today I got none - rock solid. Looking through the log data of today's flight, and previous flights when I did get alerts, did not provide further insight. Probably because I set the time interval at 3 sec - longer than the duration of a typical signal loss event.

@Wayne, indeed the XM+ only has S-Bus out; the M+ has both S-Bus and S.Port. I guess I could try to use the S-Bus out instead and see what happens, but I'm completely happy with the way it currently works (and S-Bus being on pin 4 makes it harder). Now that I know it works, going forward I'll probably solder an extension cable directly onto the M+ and forego the pins.

The primary reason for my interest in redundancy is for protection of my Duo Discus, a beautiful 3m scale glider I don't want to lose. But considering the negligible cost of the M+, I'll be using them in more of my gliders. The main difficulty is installing them at the end of a long tail boom of an existing model, as they often don't have suitable openings back there for external access. If anyone has clever ideas for shoving and mounting a small Rx down a narrow 3 ft tube, let me know!

 

[Wayne]

Can you post some pictures of your setup? I think there is some confusion with the port assignments. S-port and S-bus are 2 different things and are not interchangeable. For added confusion, F-Port is a combo of both and can do it all.