I maiden a large gasser with a two RX8R-Pros connected to a RB-20. As I was looking at the telemetry stream after the flight, I noticed several issues where the RBS >0. The telemetry was logged at 0.5 s intervals. Specifically, there were several instances of "Physical Connection Lost" (16), "Signal Lost" (64) or (much more rarely) both (80=16+64) all coming from the same Rx 1 (a brand new Rx, which I bought from Aloft a few months ago). I suspect a wiring issue, but I am wondering how the RB-20 can differentiate between the two. Does anybody know what are the conditions that trigger the two events? It would help diagnosing the problem.
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Meaning of Physical Connection Lost and Signal Lost on RB-20 telemetry stream
- Thread starter ululi1970
- Start date
Konrad
Very Strong User
"Physical Connection Lost": look for cold solder joints and improperly crimped harness pins. There are some concerns with the "pro".
forum.alofthobbies.com
A classic trouble shooting technique is to swap the part.
If the fault follows the part (rx) then the problem is likely with the RX. If the fault stays with the port RB-20 then look to the harness and/or the RB-20. If the fault stays with the port then swap the harness. This way one can isolate the problem to the RB-20, harnesses or RXs.
"Signal lost": indicates to me an RF issue separate from a power supply issue. Is your Rx isolated from vibration? How are your antennas oriented? How is the antenna connection to the the rx board?
RX8R-pro
Just learned via the product reviews that there is a problem with a production run of these RX8R-pro. How can one tell if I own any of these? I think I have about 1/2 a dozen still not used, from what may be an early production runs. I'm using one and it sems to be fine. But the others are...
forum.alofthobbies.com
A classic trouble shooting technique is to swap the part.
If the fault follows the part (rx) then the problem is likely with the RX. If the fault stays with the port RB-20 then look to the harness and/or the RB-20. If the fault stays with the port then swap the harness. This way one can isolate the problem to the RB-20, harnesses or RXs.
"Signal lost": indicates to me an RF issue separate from a power supply issue. Is your Rx isolated from vibration? How are your antennas oriented? How is the antenna connection to the the rx board?
Thanks Konrad. Actually, rereading the manual, it's not signal lost, rather it is "No signal". Since the telemetry also logs "fail safe" and "frame lost", I would assume that
"No Signal" means no SBus signal. I am hoping that Wayne can clarify this issue. But your suggestions are valid: I had tested the system before on the ground with the engine off, and no problems surfaced, so this seems to be a vibration induced problem. Unfortunately, I busted a landing gear and so I will have to fix that before I can do any more testing with the engine on.
"No Signal" means no SBus signal. I am hoping that Wayne can clarify this issue. But your suggestions are valid: I had tested the system before on the ground with the engine off, and no problems surfaced, so this seems to be a vibration induced problem. Unfortunately, I busted a landing gear and so I will have to fix that before I can do any more testing with the engine on.
I did some testings (engine off) by unplugging alternatively one or the other Rx with the RB-20 on. I get weird results: Sometimes, I get telemetry lost when I unplug one of the receivers (does not matter which one), sometimes I do not. I thought that telemetry could be handled by either receiver?
The manual states that Rx cannot be hotplugged, but how is that different from some faulty wiring that may cause intermittent problems with one of the Rxs?
This is precisely what a redundant system is supposed to be!
I wish somebody could post some clear indications on how the system is supposed to work, and how to test it.
I am beginning to feel frustrated with this whole FrSky thing.
The manual states that Rx cannot be hotplugged, but how is that different from some faulty wiring that may cause intermittent problems with one of the Rxs?
This is precisely what a redundant system is supposed to be!
I wish somebody could post some clear indications on how the system is supposed to work, and how to test it.
I am beginning to feel frustrated with this whole FrSky thing.
Konrad
Very Strong User
Sorry I have no answers.
You do ask some good questions.
From the manual;
RB-20 doesn't support hotplug. When RX1 or RX2 is replaced halfway, RB-20 needs to be repowered on.
What does the term "hotplug" mean? Are they trying to define it with the following sentence? And what does "halfway" mean?
When RX1 or RX2 fails (replaced halfway) I assume the RB-20 latches to the good RX and that a power reset is needed to release this latch. (I assume this has something to do with the synchronization pulse).
Having issues with the power supplies (moving back and forth from say bad wiring) appears to work as long some battery (circuit) has sufficient power.
"Telemetry lost telemetry found" is a normal thing for FrSky. It is often a result of overloading the front end of the receiver (swamping). Try keeping the TX and RX separated by 3 or more meters, this annoyance should disappear. (This is actually a good thing as it is an indication that the TX's receiver has very good sensitivity).
I feel your pain with the poor documentation with FrSky and many products on the market today. Far too many firms think that they can eliminate proper documentation and rely on user generated content. User generated content is great but it is no substitute for proper documentation by any OEM! (So much for the information age)
All the best,
Konrad
You do ask some good questions.
From the manual;
RB-20 doesn't support hotplug. When RX1 or RX2 is replaced halfway, RB-20 needs to be repowered on.
What does the term "hotplug" mean? Are they trying to define it with the following sentence? And what does "halfway" mean?
When RX1 or RX2 fails (replaced halfway) I assume the RB-20 latches to the good RX and that a power reset is needed to release this latch. (I assume this has something to do with the synchronization pulse).
Having issues with the power supplies (moving back and forth from say bad wiring) appears to work as long some battery (circuit) has sufficient power.
"Telemetry lost telemetry found" is a normal thing for FrSky. It is often a result of overloading the front end of the receiver (swamping). Try keeping the TX and RX separated by 3 or more meters, this annoyance should disappear. (This is actually a good thing as it is an indication that the TX's receiver has very good sensitivity).
I feel your pain with the poor documentation with FrSky and many products on the market today. Far too many firms think that they can eliminate proper documentation and rely on user generated content. User generated content is great but it is no substitute for proper documentation by any OEM! (So much for the information age)
All the best,
Konrad
E
EstevanB
Guest
I am having similar issue:
I also have a gasser with a two RX8R-Pros connected to a RB-20. But between the RX8R-Pros and RB-20 I have a CORTEX Gyro with redundant serial inputs and outputs. After 5 flights, I got RBS=80 several times. Two flights had no RBS issues but 3 had 3 to 5 ocurrences of RBS=80. The telemetry was also logged at 0.5 s intervals. 80 means "RX1 Physical Connection Lost" and "RX1 Signal Lost" I was suspecting a wiring issue, but redid my wiring for this flight.
In my case, I am not sure if this could be caused by the Cortex PRO.!?
I have bound RX1 as CH1-8 TELEMETRY ON and RX2 CH9-16 TELEMETRY ON.
I tried to match RBS errors with current draw amps and RX voltage on telemetry and found nothing suspicious.. Voltage has always been good. So does RSSI. always above 50%.
I do have other 2 XM+ connected at the RX8R-PRO SBUS IN as a backup RX. So in total my setup has 4 RX's
I will try and swap RX's in the RB20 and see if I bet the same error but for RX2. This should confirm if the error is on the RBS or before it.
Not too long ago I moved my fleet completely from Spectrum to FrSky. All my planes are FrSky and I really like their products. But they could care less for their customers.... I am never able to get support from knowledgeable people...
Let me know if you have any progress on your troubleshooting. I am really interested in the outcome.
Thanks.
I also have a gasser with a two RX8R-Pros connected to a RB-20. But between the RX8R-Pros and RB-20 I have a CORTEX Gyro with redundant serial inputs and outputs. After 5 flights, I got RBS=80 several times. Two flights had no RBS issues but 3 had 3 to 5 ocurrences of RBS=80. The telemetry was also logged at 0.5 s intervals. 80 means "RX1 Physical Connection Lost" and "RX1 Signal Lost" I was suspecting a wiring issue, but redid my wiring for this flight.
In my case, I am not sure if this could be caused by the Cortex PRO.!?
I have bound RX1 as CH1-8 TELEMETRY ON and RX2 CH9-16 TELEMETRY ON.
I tried to match RBS errors with current draw amps and RX voltage on telemetry and found nothing suspicious.. Voltage has always been good. So does RSSI. always above 50%.
I do have other 2 XM+ connected at the RX8R-PRO SBUS IN as a backup RX. So in total my setup has 4 RX's
I will try and swap RX's in the RB20 and see if I bet the same error but for RX2. This should confirm if the error is on the RBS or before it.
Not too long ago I moved my fleet completely from Spectrum to FrSky. All my planes are FrSky and I really like their products. But they could care less for their customers.... I am never able to get support from knowledgeable people...
Let me know if you have any progress on your troubleshooting. I am really interested in the outcome.
Thanks.
I have not made any progress yet. The landing gear rails had been improperly repaired by the previous owner, and I had to spend some time
to set them right. Ground test still shows RBS 16 and 64 popping up, but only with the engine running, which suggests a bad crimp or a cold joint someplace. Have you tried swapping the wires going to rx1 with the ones going to rx2?
That is what I am planning to do first. If the problem does not migrate, it may suggest a problem with the RB-20. If it does, I will replace the wires, and go from there.
I have a R9 that I can use in place of a one of the Pros. It is going to take some time...
to set them right. Ground test still shows RBS 16 and 64 popping up, but only with the engine running, which suggests a bad crimp or a cold joint someplace. Have you tried swapping the wires going to rx1 with the ones going to rx2?
That is what I am planning to do first. If the problem does not migrate, it may suggest a problem with the RB-20. If it does, I will replace the wires, and go from there.
I have a R9 that I can use in place of a one of the Pros. It is going to take some time...
Konrad
Very Strong User
No, but we have paid for a product (which, BTW, is not really that cheap) and we have some questions about the product: we are not asking for help to set up our planes, etc., we are only asking "when the telemetry says so and so, what does it really mean?"
Konrad
Very Strong User
So who are you asking? The retailer or the OEM.
The retailer only gets a mark up of around 30% . The retailer often doesn't have anymore technical insight from the OEM than you have. The retailer may have more experience with reports he receives of issues. And may be able to draw upon this knowledge set to help. His only other recourse is to offer replacement of faulty products.
Now I don't know if the product is faulty, or if it is working as designed.
I do agree that with many Asian OEMs, many terms are ambiguous.
While $60 isn't expensive I'd expect better define terms and nomenclature. This documentation issue is plaguing FrSky and results in a rather poor customer experience. While for the most part I like FrSky products this documentation issue is killing FrSky's reputation! This is a core issue with FrSky's corporate structure!
The retailer only gets a mark up of around 30% . The retailer often doesn't have anymore technical insight from the OEM than you have. The retailer may have more experience with reports he receives of issues. And may be able to draw upon this knowledge set to help. His only other recourse is to offer replacement of faulty products.
Now I don't know if the product is faulty, or if it is working as designed.
I do agree that with many Asian OEMs, many terms are ambiguous.
While $60 isn't expensive I'd expect better define terms and nomenclature. This documentation issue is plaguing FrSky and results in a rather poor customer experience. While for the most part I like FrSky products this documentation issue is killing FrSky's reputation! This is a core issue with FrSky's corporate structure!
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On the rcgroups thread devoted to the new accst firmware, some people are using the RB-20 to log events during tests. Today, somebody reported tests where
they turn on a microwave 3m away from the rx (connected to a RB-20) to simulate a noisy RF environment. Well, would you believe that RB-20 reports
Physical connection lost for both RX? To me, that does not make any sense: I would expect the microwave jamming to trigger either a Lost Frame or a Fail Safe event,
not something that should be related to physical wiring problems...
they turn on a microwave 3m away from the rx (connected to a RB-20) to simulate a noisy RF environment. Well, would you believe that RB-20 reports
Physical connection lost for both RX? To me, that does not make any sense: I would expect the microwave jamming to trigger either a Lost Frame or a Fail Safe event,
not something that should be related to physical wiring problems...
I did some more testing this afternoon with the engine on. I swapped the Rxs SBus and SPort leads, and still I got occasional Signal lost or Physical connection lost or both on Rx 1. If the problem had to do with wiring and/or the Rx, swapping them should have resulted in problems on Rx2. So, (thank you Konrad!) that means the problem is the RB-20. I carefully inspected the PCB board, but as far as I can tell, I cannot see any sign of cold joints on the pins. This, and the fact noted above, seems to indicate a problem with firmware?
Do you know with firmware are running on the RB-20?
E
EstevanB
Guest
I’m using firmware version 180724. I have also switched rx1 with RX 2 and got the same error code. So it is not wiring issue for sure...
FrSky have not replied to my emails about this issue
FrSky have not replied to my emails about this issue
I ended up buying a new RB-20 from Aloft, and yesterday I had a chance to try it out. Same problem: random occurrences of RBS 16, 64 and 80. I changed cables, swapped RXs, nothing. The controls are solid, and the rest of the telemetry has no issues. No telemetry lost alarms. Running V2.1 fw on the Rx.
I will try the other RB-20 on a different gasser...
I will try the other RB-20 on a different gasser...