weird problems

[Sebas600]

hey, I'm just putting together my octo.
tested my engines and all was working.
now i hooked up my pc to the wkm and now.... the LED is constantly flashing red.
no engine response
pc software indicates cfg-err8
when trying to calibrate (s-bus) there is no visible sign of the signal coming in to the wkm
also no signal on the U port

software also shows MC output on but ESC's aren't powered at all.

anyone had this problem? what am I doing wrong? any suggestions?

thanks!

 

[BorisS]

Seb what does it say for the error cfg-err8 ? dont remember ?

 

[BorisS]

that the answer i got in RCgroups when i had the same error with my first build

CFG-ERR(8) is a configuration error. It always happnes after you upgrade the system or abnormal tx calibration. If you have this problem, please calibrate the tx and reboot the controller. It can also happen after you have an upgrade. If in this condition, please defualt all parameters, re-calibrate tx and reboot the controller.

 

[Sebas600]

Thanks Boris, but a reboot as in hard reboot, pulling the power plug?
I have tried to recalibrate and put all on default, but the calibrate function doesn't seem to work.
Is it maybe that I have only put in the s-bus wire to the tx?
does it need a separate power line?

 

[BorisS]

Your futaba needs extra power. Is there a light on on the futaba RX ? You can use the bec output from the pmu module to power the rx. So separate the white cable from the pmu from red and black. White goes into x1 or x2 don't remember please check to tell the mc the voltage state. Blak red output from the bec can be used for the RX.

The mc itself should be powered with the can bus connection coming from the pmu. Post a picture of your setup if you still have problems !

Boris

 

[Sebas600]

That's quick! thanks again. the power light on the rx is on. it does get it's power for the mc via the v-sen
x1 is s-bus
x2 is v-sen witch powers the rx via the mc red+black and shows battery status via white wire, at least that's what i assume.

so what is the difference from taking the power via the mc to directly form v-sen?

the setup has worked before only just stopped after the update:dejection:

 

[BorisS]

Ah okay if it worked before than it's a DJI prob. Update again power cycle it like recommended. Set everyting to default in tx configuration and see if it works. I had the prob a couple times upgrading again solved it. If it doesnt solve it something wrong and you will have to contact DJI.

Boris

 

[Sebas600]

updated again and again and... it's like disneyland.... magically it works! thanks for all the help!
engines still not running but at least it sees tx movement now.

 

[BorisS]

keep me posted because of the motor output if it dosent work maybe i can help you !

Boris

 

[Sebas600]

got it working Boris! thank you for your time! here some pics of the build, in the dark with 18W of LED power :nevreness:

View attachment 1552View attachment 1553View attachment 1554View attachment 1555View attachment 1556

 

[BorisS]

Hey Seb, looking very good ! keep us updated about your progress on tuning it. One advice with the WKM although it hurts a little for a setup like yours or mine considering the mz CS 8 build, WKM performs better with smaller and lighter props. But you are on the right track I think the axis you have on, pretty sure they have 780 KV, aren't that low on KV so its positive concerning WKM !

 

[Sebas600]

I have the Axi 2814/22 and the APC 12x3.8 SF props
If this works out i was thinking to buy CF props, sins they are lighter and black... Much better then the gray apc's

Have gone for these because they showed most effecient in ecalc for my plans.

 

[BorisS]

Japp CF would make sense. Look at the props in the MK shop 11 grams 12 3.8. WKM setups really like lighter props ! Only problem they come 5mm you have to drill them to 6mm. Which can be a hassle and you have to balance them again. Drilling only works with a stable setup otherwise they are ruined !
Boris

 

[Sebas600]

I found these, from same shop as my frame. they are a bit cheaper and no drilling required.

http://shop.jet-1a.com/product_info...=1816&osCsid=f4cfc0f51984d7a1545dbebe47f3bbbc

think I'm going for a first test later today, it's perfect no wind at al but foggy dough.

 

[BorisS]

Seb those are the Aerobot i wold really not recommend them ! And compared to the MK they are 7 grams heavier. They are just as heavy as APC so there it acutally no big reasons anymore to switch to them, only maybe because of stiffness etc.

http://www.lcc-shop.de/index.htm

under props is also an option but you are right they are all very expensive !

 

[Sebas600]

they are expensive and the finish doesn't look that smooth as the ones in the mk shop.

the whole is ready but waiting on servo tester to balance the motors and props.

when running the engines without props the resonance in the frame is huge! it produces a squeal that blows my eardrums!

and I was wondering sins I use 40 amp sec's and the engines can only take a burst load of 25a it seems to me that 100:40x25=62,5% of my throttle range is used? or am I mistaken on this?

oh and here some pics (yes again with phone)

View attachment 1558View attachment 1559View attachment 1560

 

[BorisS]

The ones in the MK shop are the best. I have the aerobot here and i have had the LCC in my hands.

Ranking

1. MK CF
2. LCC
3. Aerobot .... crap ! Marketing oh its carbon how cool !

no i wouldnt worry about that. If your ESCs can provide more A than demanded by the motors you are on the safe side, you just have oversized in a physical measure your ESCs and could have saved weight and space.

This whole throttle range calibration I have never understood to be honest and I have never done it for my WKM setups, since i wasnt aware of it from my MK bird not needing it. I cant talk about manual mode but your actual throttle command in attitude mode will not be transmitted directly to the ESCs anyway, but interpreted by the WKM MC. I also dont find any refernce to calibrating the ESCs in the WKM manual, but please correct me if i am wrong.

Resonance without props is also normal wouldn't worry.

Very nice setup and very clean work I like it. You might experience a long SAT lock down time since you have the GPS close to the IMU, guessing that the IMU is right under the plate you mounted the GPS module on. At the same time though i also change my HEXA and dont have the GPS on the rod anymore and dont perceive any difference to before. But i also have two 2mm thick carbon plates between the IMU and the GPS.

Consider that you will probably not have your Center of Gravity in the middle of your frame since you have the Lipo and the AV 200 in a row under the Copter. Dont know how far you have gotten into the DJi WKM conf tool. But you will have to probably consider this when you tell the tool were you IMU and GPS is located in respect to the CG.

Boris

 

[Sebas600]

thanks for the info.

I have the gps above the IMU, with is in the middle of the whole octo.
the gps is mounted on a blank 1,5mm PCB plate, so the bottom is copper plated, my thought was that this would shield the gps from everything below.
the IMU, MC, PMU, RX, led power, radio BEC, servo BEC, is all under the gps and also mounted on the same 1,5mm PCB
under that are the ESC's with the heat sinks mounted on a aluminum plate witch is spaced from the carbon frame
the idea was that the ESC's can vent very good this way.
also the other point was... there was no other way to do it. I like it to look good without wires sticking out everywhere op tripping the sec's to the booms.
the only thing not looking great are the LEDs but that doesn't matter cause when they are on you can't look in that direction :highly_amused:

about the COG i'll have to work a bit on that. haven't mounted anything in the av200 yet. haven't really decided on witch cam to buy. think i'll play with my go pro first. have a good sanyo as well.

the focus will be on video. payload max. 1200 grams.

 

[BorisS]

you shouldnt have any big probs with that setup, ESCs close to the other components also shouldnt be a big prob. I did the same with my hexa and I think Ken RTRyder also with his CS6 build. GPS you will see what happens. I have experienced that is takes a lot longer for the WKM to lock the SATs when it is on the ground. I take the bird up right away and have it locked with no red blinks after 30 secs. This could be dangerours though considering fail safe return to home autolanding since i dont know when or how it sets the landing point. But if its a open field it shouldnt be a problem.

With this bird and the Axis you will have a lot of cam and payload options.

 

[Sebas600]

Yeah test flight done! the wkm is awesome! only flown my KK tricopter and x650v8 before. this is something else! very easy and calm. to bad had no lipo alarm with me. short flight.

okj like that :tennis: