Possible bug in A2 built-in receiver.

Received my A2 a few days ago and finally had some time to finish up the install last night. Binding with Futaba 14SG was relatively straightforward, but upon first spooling up the S800, there was an occasional "twitch" or "bump" on certain motors. Certainly didn't dare do anything but get her light on the gear. Upon further inspection while hooked up to the assistant, I noticed that the aileron, elevator, throttle and U channels were occasionally changing, just for a split second. I switched to an external R7008SB and control through S-bus on X2 works flawlessly. Quite impressed with the stability actually. Nevertheless, the built-in DR16 appears to be totally unusable and/or unreliable for me.

Wondering if anyone else who has the A2 up and running has observed this behavior. You'll hear it in the motors if you spool up, or you'll see it in the assistant software as the above mentioned channels randomly switching positions, then coming right back to actual stick/switch position. If this sounds familiar to anyone, I can re-bind the DR16 and record a video for confirmation.

Brad
 



Ha! The sad part is that that's the first thought that popped into my head, and through the previous purchase of 2 WKMs, 2 NAZAs and a WKH, that I've been brainwashed into believing that it's all OK, and eventually I'll be able to update my way into a working product. In all fairness, I knew I was buying into a brand new platform, and that always means issues. Hopefully it's a SW fix, and not gonna mean a MarkII product to get it right.
 





Spoke to Greg at Atlanta Hobby this morning, and emailed him a description of the problem, which he will be forwarding on to DJI. Who knows how long it will take to get an answer, but I will share with the forum as soon as I find out more. In the interim, I'll fly with an external SBUS receiver. Hopefully it's a software fix, but if the system needs to be replaced, I'm sure Atlanta Hobby will take good care of me. They always have.

I really don't know if this odd behavior is isolated to my system or all A2s, which is why i put it out here. Thinking a video of what it does would be helpful for others to understand what i'm talking about. Will see what i can put together this evening.
 



So it seems that this problem is only on channels with F/S set. Well that's all fine and dandy, but i would like to set F/S levels for throttle, gear and flight mode, but those with be jittery during normal use if i have F/S on anything but HOLD. Here is a video of the problem. For the purposes of this discussion, F/S is enabled on aileron with a position of 0%.

https://www.youtube.com/watch?v=J8R1WUyh-Lg
 

Maybe I overlooked the obvious, and just assumed that failsafe needs to be configured on the transmitter for the DR16 to work in failsafe mode when the TX is lost. Failsafe still shows active (according to the LED) when no failsafe is enabled on any channel, and the radio is turned off. Of course there is no mention whatsoever of any deviation from the failsafe configuration practice that we are all used to with all previous DJI products, but we're all mind-readers, right? So the end result, it seems, is that if you follow the old practice of setting up failsafe in the radio, the system goes haywire... When you go against all logic, and SKIP any sort of failsafe setup in the transmitter, all works the way it's supposed to. If this is actually the case, DJI, PLEASE MAKE THIS CHANGE CLEARER IN THE DAMN MANUAL!
 

ddikie

Member
Hi,

I am going to flight test A2 on an S800 evo this afternoon..in 3 hrs time..I have set up a go home switch SD and also a forced failsafe switch on SG all seems ok in the controller, i am not sure i understand what you mean Wbboycofc? ..i checked the sticks and there appears to be no issues..anyway will report back on my flight and keep my fingers crossed.
 

mongo

lost soul
wacky failsafe stuff is something that happens with other non factory rx when used with FASST systems.not to surprising it happens with the one in the A2.
 


wacky failsafe stuff is something that happens with other non factory rx when used with FASST systems.not to surprising it happens with the one in the A2.

Hi,

I am going to flight test A2 on an S800 evo this afternoon..in 3 hrs time..I have set up a go home switch SD and also a forced failsafe switch on SG all seems ok in the controller, i am not sure i understand what you mean Wbboycofc? ..i checked the sticks and there appears to be no issues..anyway will report back on my flight and keep my fingers crossed.



ddkie,
I'm not talking about a program mix forced failsafe assigned to a switch. I have that setup too and it works perfectly. I'm talking about failsafe positions assigned to a channel for loss of signal. I'm curious if you assign failsafe preset positions on your transmitter, if you will see the same behavior on those channels in the assistant. As mongo pointed out, this wacky failsafe stuff is common with non-factory rx (this is new to me, as i am a recent JR convert). I guess it should just be clearer in the documentation not to setup failsafe levels in the tx as was done with previous systems.

look forward to hearing about your flight!
 

Tahoe Ed

Active Member
Make sure if you have a Futaba Tx that it is set to Multi. There are various flavors so make sure that you are using the one that is appropriate to you Tx.
 

Tahoe Ed

Active Member
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I just received a DJI A2 today. My first impression on opening the box was wow! Looking that the quality of the construction, gorgeous aluminum cases, and the size of the GPS, this is a worthy upgrade over the WKM! I did not have my WKM with me and compared my Naza V2 GPS to the A2. The Naza V2 GPS is 45mm in diameter the new A2 is a whopping 60mm. It just looks huge. The included GPS mount is now 5mm in diameter and 16 cm, 12 cm and 8 cm in length. The have also added some kind of filter inline on the can bus cable.

The MC contains a Futaba compatible FASST Rx and it has two small ports for Spektrum satellite receivers. They have added an inline can bus connection between the IMU and the MC along with the usual one on the connection between the GPS and the MC. They have also moved the micro USB port from the MC to the LED like the rest of their controllers. The LED has the BT module so you will be able to control the parameters from your iOS device the same as the WKM. It is a nice feature when first setting up the A2 and when flying in different environments. This should be important to the pros that fly to different locations. The App allows for IMU calibration and Compass calibration. No computer to carry around.

The PMU is the same size as the current but in aluminum

I have the A2 installed on my S800 now. I have the vibration isolation mount but I was told that with the A2 we can go back to the original mount on the main board. That is what I did. In order to make sure that I had space around the IMU, I wrapped it in tape until it was a tight fit in the hole then I stuck it down with the double sided tape from DJI.

I have the MC and PMU mounted on the underside of the bottom plate. That way the antennas have a view to the rear and I have easy access to a can bus port for my iOSD, Zen15 or my Data Link. The BT LED is connected to the PMU and mounted on one of the rear arms with Velcro. The manual says to have the antenna mounted up, so the lead to the LED must be mounted up. Make sure that you follow the DJI connection guide to the letter. There is a note that many may overlook, “CAN 1 and CAN 2 ports are working independently, devices connected to them are not interchangeable. IMU and GPS Pro to CAN 1, LED-BT, iOSD, Zen 15, to CAN2, PMU to CAN 1 or CAN 2.” My edit to the manual to make it clearer.

Here are some pictures of my install.

I have done the updates to the various subsystems on the A2. It is no longer a single upgrade but you now have firmware for the IMU, the GPS Pro, the LED, the MC etc. I think that there are 6 separate subsystems now that have their own firmware. I am flying with a Futaba 8FGS and starting to set up the Tx for this controller. The binding process is very simple. Turn on your Tx in a new model and the power up the A2 and press the bind button. It could not be easier. Once I have it flying will with the Futaba I will try the Spektrum satellites that are supported with this MC. Equality for all.

If you have a Futaba, 8FGS or higher, you will love the A2. The channel mapping is huge. Some have complained that it is not 18 channel but I am happy with what I got. Make sure your Tx is set on Multi, there are different varieties so check your Tx manual for the appropriate one for you specific Tx.
 

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To add to this, if you are using Futaba FASST-MULT with the built-in DR16 RX, you do not need to configure fail-safe channel positions for throttle or U channel. The A2 will automatically detect loss of signal on the rx and enter failsafe mode. Configuring failsafe preset positions on these channels will result in random channel jitter during normal use. Failsafe on all channels should remain set on HOLD.
 

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