Hey there, I have been trying to fix the radio calibration problem which is not getting calibrated due to reasons I am unable to find yet. Here are a probable list of problems I have figured out. Please help me out flying my quad.

1. Wrong connection of FS R9B Rx with APM 2.6 board.
2. Wrong tuning of FS TH9X with Rx.
3. Any mistakes of steps followed during first flight setup.
4. Hardware problem.

Someone please help me out.

Mousum, welcome to RCIndia! 

Have you checked the receiver output using a servo or ESC? Does the radio calibration screen show proper stick inputs?

If the receiver is giving proper servo signals then check connections with the APM. If you have access to another radio set try it with that.

We can guide you better if you provide some pictures of your setup.

Thanks for your kind gesture sir. Ya I have checked connecting esc with the receiver, but it did not work. Is it a hardware problem ?

Have you completed the binding procedure of the transmitter and receiver? If yes, try controlling a servo with the receiver.

Y binding is done. I tried connecting escs without apm board.Dint work. Connections and all were correct. Have to check using servo.Can you provide me your mobile number sir ?

I can't help you much over the phone without seeing the setup. Why don't you post pictures of your connections and screenshots from mission planner. That way others will be able to help too.

Here is the setup of my quad. Image attached...I have done calibrations like compass, accel and all succesfully...But radio calibration was not done...red sticks were not shown upon changing the Tx trims and switches to max n min positions...

Get a closer pic of just the APM and rx.

I did the radio calibration in the same setup without much problem. I am also beginner. You can see the thread http://www.rcindia.org/multirotors/building-apm-2-52-quadcopter-with-st360-kit/ where I have posted the relevant videos using which I have managed to calibrate the radio successfully. In fact it was easy..only calibrating the Auxiliary channel requires some patience.

Inputs 1-4 in APM goes to channels 1-4 of the receiver. That is apparently ok in your setup. Can't see the signal and earth wires clearly but if signal wire is upwards in the Rx and inwards in APM then its ok.

Wrong tuning should not happen with the default setup of the Tx. Did you change anything there?

How do you know that binding of Tx and Rx is ok?

This implies either a faulty receiver or improper binding. Just try controlling a servo and the problem will become clear.

Binding was done with proper steps  taken...red light of Rx blinks constantly once binding is done...

Closer view attached

Dear sir,, there was one more major problem that I faced...that is my apm 2.6 board is not powered up by USB only...so I had to connect the power module...so is there any problem in my board ??

That's not how it should be.

The red light blinks rapidly in binding mode, and once the binding process is completed, it should stay lit .

Oh yes,,,I did that properly sir...but why my apm 2.6 is not getting powered up by USB ?  It needs the battery to be powered...

Now, you may try it like this ;

Connect a ESC cable directly to Ch3 on Receicer.
Connect a Motor to ESC (no prop )
switch on transmitter, keep the throttle stick low .
Power the ESC with a LiPo.
Check the LED status on Receiver and post the result (Check whether the Red Led on receiver is solid) .
If the red Led is solid lit , apply a little throttle ,and the motor should start (If esc calibration is already done)

Do the above steps, and post the result.
By the way do you have a Servo with you ?

APM should power up just with a USB connected.
detach any other connectors from APM, and connect USB, check what happens. also check your USB cable (Check with another cable if you have spare.)

Yes sir,,i did that...everything worked fine...led lit solidly...throttle applied...motor worked...

Ok now, receiver and radio is confirmed to be working fine, No more worries about that.
What happened with APM ?

Nope sir,,,its not working on USB anymore...So wat do i do now ?   To power it I must have to connect Lipo...thats the problem right now

Did the APM work before with just USB?

Try with another USB cable, and also try connect to another port on PC.

No sir,,,it never worked with USB alone before too..I have tried other USBs and other ports,,,other systems too,,,

Maybe the USB port is damaged. When you power it using a LiPo, can you calibrate receiver input now?

No sir,,,I tried,,,I am using factory settings on Tx which is in Heli Mode1 PPM...Rx & Tx are binded...but during radio calibration on Mission Planner the roll, pitch,yaw and throttle values are not getting changed...accel and compass were done and also firmware installed successfully...should I do any change in factory settings on Tx...should i make it Acro mode or wat else is the problem sir ?

It is many times seen that USB splitters are giving proper/full power. did you used any splitter or usb cable extension wire? even, one case usb port of on front of the cpu cabinet (of the computer) was not giving enough power but same time on-board usb ports worked fine.

Thank you sir,,,will try it and post the result asap....

You have to use Acro mode in transmitter , not Heli mode.
Better create a new model in transmitter with acro mode.

I want to give a brief summary of my doings and problems. Please suggest me what should be done next to make it work.
 Doings: 
1. Used Tx in factory settings except I have changed from Heli to Acro mode for Radio calibration.
Problem :
Radio Calibration still not happening.

2. Tried powering amp 2.6 via USB only by removing and putting again the JP1 jumper.
Problem : Still apm is not powered by USB only & it was never done earlier also.

3. Checked Rx Chnls using ESC. Rx is found to be OK.

4. Checked apm powering by connecting many USBs in different ports & in diff systems too. Not working at all.

5. Calibrated all params like compass, accel & also installed firmware by powering apm via Lipo & connecting to Mavlink.
Problem : When radio calibration is up there.....FAILURE !!!!!!

6. My Tx was in Acro mode....stick set mode 2....PPM...Rx CH 1-4 serially connected to apm CH1-4....
 WHAT SHOULD I DO NOW.......?

whats the status of red light in receiver when connected to apm?
also check

put the jumper jp1,

Connect only  rc input, USB and just one ESC

disconnecting all other cables(power module, gps,compass, ESCs etc...)

check the status now.

In the picture in your reply #6, the receiver LED doesen't seem to be on. Is that still the case?

If you have access to a multimeter power up the APM and check the voltage on any of the inputs '+' pins.

Yes sir,,I did that...disconnected all the modules(PM,Compass,GPS..) and only connected rc input and one ESC,,red led of Rx is solid and corresponding motor worked....what to do next ??

Now you need to complete the radio calibration.

NO its working fine sir...just tell me the proper connection of Rx to apm plz...I have connected CH1-4 of Rx to CH 1-4 of apm input serially and using PPM Acro mode in Tx for radio calibration and still problem persists...

Did your motor work while connected to the APM or directly?

Ya motor worked,,I have checked connecting the ESCs one by one also and corresponding motor worked,,,but they got only throttle values not others...plz tell me or give me some images of proper interfacing of channels and everything...cuz still im unable to calibrate radio channels...

Try connecting it like this:

Can you please say what d'you see in the mission planner radio calibration screen ? Nothing moves when you move the sticks in your radio ? Are all the sticks shown centered in the missionplanner ? Is the throttle channel shown low in there ?

Yes sir,,nothing moves when I change the sticks,,,,all values remains same,,,,nothing happens at all,,,and when I click done,,,it says BAD channel 1 input error...

Tried this one,,,not working sir...during PPM mode,,,(If you are using a PPM Receiver, put a jumper on the “S” inputs of channel 2 and 3, and connect the PPM input to channel 1)....I dont understand it sir...

Let's see:

1) Your receiver is giving out proper signals as you tested ESCs directly.
2) You can calibrate accelerometer, compass etc. so your APM firmware is working properly.

The only conclusion here is that either
1) you are improperly connecting the receiver and APM or
2) the input line on APM is faulty.

Try this:
1) Connect only receiver to APM, power up with LiPo and connect to computer.
2) While the APM is powered up, post one picture of APM + receiver and one screenshot of radio calibration window.

Ya,,,I tried the connection you have given in the image sir,,that too not working,,,now I have done as you told in the last reply and here are the images...

Can you please post one more picture of radio calibration screen with receiver wires not connected to APM ?

It could be that the receiver isn't receiving power. Rest seems fine.

Check the voltage on the inputs '+' line using a multimeter.

If Rx wires not connected to apm, how will it get powered ??
Checked voltage across I/O ports...shows around 5 V throughout,,,Lipo is fully charged....Tx also sends all values which I got checked on its display...Only problem I guess is with apm...which is not getting powered with USB alone...and may be there is a problem with apm & Rx connection...I dont understand what it means by saying PPM mode and connect Jumper on 2 & 3 S input of apm chnls...and connect PPM input to CH 1...where from PPM input Comes?

SOMEONE WHO HAVE WORKING QUAD COMPRISING FLY SKY 8 CH TX & RX WITH APM 2.6 EXTERNAL COMPASS & GPS IS SO HONESTLY REQUESTED TO GIVE ME PROPER IMAGES OF ALL CONNECTIONs ASAP.......

Can't see any problem with APM - receiver connection . I was asking you to remove receiver connections from apm, and connect it to missionplanner this was for checking whether apm detects missing rc inputs ,so please post pic of rc calibration screen with out your receiver channels connected to apm

I know this being question have been asked several times , but are you sure , the red led on receiver is staying lit , when your receiver is being powered from APM ?

Yup...red led is solid and binding was perfect...

Yes sir,,without connecting the Rx with apm,,,,in mission planner it show no rc connceted,,,,and here is the image of rc calibration screenshot

I am working on my quad. It still does not fly because I haven't got time to mount it on a frame. But all calibrations and settings are complete. Connection pix are available in my thread http://www.rcindia.org/multirotors/building-apm-2-52-quadcopter-with-st360-kit

@mosum, I think that was a firmware issue or bad calibration that you done before.
Try these steps.

reset parameter to defaults from advanced parameters menu,
Disconnect and reconnect power (USB/battery)

While disconnected in mission planner goto initial setup
Click wizard and complete all the steps.


Edit:

If the problem still persists then that should be a hardware problem and the voltage regulator in apm need to be replaced.

@akhilzid...
 Finally i have done all the calibrations successfully including RADIO CALIBRATION.....It happened when I changed my mission planner version from 1.3.24 to 1.3.30.......RC calibration done with ACRO mode in Tx....ESC and all were also done....but NOW

NEW PROBLEM : What to do in Tx to fly my quad....its not getting up and instead when I use throttle it goes to one side....cant make it fly.....should I change the flight modes ?? Or should I change anything on the Tx ??

Most probably the THR_MAX value is 80. See http://www.rcindia.org/multirotors/building-apm-2-52-quadcopter-with-st360-kit/msg232996/#msg232996

But now mine gets up and flips over. I'd check that issue next. If yours flip to the other side even after changing throttle max value, you have to troubleshoot that.

In crease Thr acc

How to troubleshoot that?

The probable issues are mentioned in the arducopter wiki. The URL is in the link
http://copter.ardupilot.com/wiki/common-appendix/troubleshooting/#Copter-tilts-flips-over-or-wobbles-crazily-when-I-try-to-take-off

Have you tried taking off with the stock values? It will be easier to help you if you can provide details about your frame size, weight etc.

It's not a Tx problem. Remove the propellers and arm the board. Then check if the APM points in the right direction and the motors are moving as shown in the attached picture.

Good to know that you solved the radio configuration problem! 

hello everyone, I have done all the calibrations successfully. I have checked motor movement accordingly and connections correct. Just unable to fly the quad. One side goes up and other down. cant fly. What to do

Maybe the CW and CCW rotors have not been attached as per the diagram. Or, like it happened in my case, mismatched the output of the APM with the wrong ESC motors. I don't know if that is your case but you can check that but my quad flipped over due to that problem.

mousum - take off your props - hold the quad in your hand and tilt each axis

when you tilt towards any particular axis - the motor going downwards should speed up and the
opposite side motor should slow down.


when you have the above checked and corrected . put on your props in such a way
that the air is blown downwards for all motors ( this may sound obvious ) but this
is a very common mistake by beginners.

do the above and confirm that all is ok . and if it still does not fly . we can advise further.

CW and CCW motors are properly connected as per the diagram. Still flipping occurs.

Ya I did that..but results are negative. The motors downwards are not speeding up automatically. What to do next ?

post a picture of your quad
and a close up of the control board wiring .

Here are two pics of connections....

wiring seems okay -

refer to the pic above posted by swapnil - unplug all your motor/esc plugs
and then plug them in one by one and see if the correct motor responds.
i.e
plug one (all other slots empty ) - front right motor should run
plug two (all other slots empty) - rear left motor should run

and so on

before doing all this I trust you have selected the correct config in
mission planner ?

I once had the same issue(flipping right after throttle ~40%). For me it was caused by a misaligned compass and accelerometer. Arm the copter and give just one step of throttle, enough to spin props at some speed. Lift the copter in your hand and tilt it sideways/front-back and see if the stabilization works okay: it should apply more throttle to the lower level motors and less for the higher motors, if not the board isn't aligned correctly w.r.t motors. Also see if the GPS's front points to the APM's front. Another time it happened, it was just in tuning mode and I forgot to take off without a gps lock.

Re calibrate your compass and accl after each firmware update(some even require it) btw.

Ya I did that,,,worked properly. But still cant make it fly,,should I go to a open space or it flies from a single point ??

Depends on how balanced and trimmed your copter is, you can do this in a fairly large hall or your backyard. DO NOT tune indoors, ever. The turbulence/propwash is too damn high inside.

Please let me know what is to be done with transmitter settings for the first flight...if someone really did this tell me in details....give me a summary of first flight setup,,please

I did not do much transmitter settings, Whatever I did is available in the videos posted in the following posts:

http://www.rcindia.org/multirotors/building-apm-2-52-quadcopter-with-st360-kit/msg231083/#msg231083
http://www.rcindia.org/multirotors/building-apm-2-52-quadcopter-with-st360-kit/msg231117/#msg231117

In addition, I had to reverse the throttle and pitch channels as the direction was opposite to what was desired.

I did not set pitch curve etc. Those are not essential for getting the quad to fly. I'd probably do that when I understand the effects better.

Doing tuning right now, with a new build. I did nothing but calibrate the ESCs, RC calibrated with APM Planner and set my primary flight mode to stabilize, second on alt-hold and third on land. Channel 7 was set to turn on Auto Tune as well. Trims on transmitter were set to 0, plugged everything in and tested all motors etc. Put flight mode switch to stabilize.
Hold arming position for about 15 seconds to start in auto trim mode. It should start up and fly properly if everything is in order.

The process is well documented in their wiki site and there's an 8 part youtube video series on it as well.
I am also afraid that it might be faulty parts? Have you checked if all sensors are working, no interference etc?

mosum - just verify that the motors are connected to the right port in the apm - that
is most essential . transmitter setting will come later. if the motors are not speeding up when
the arm drops then no amt of settings will help you.


@santanucus - pitch curve is applicable to variable pitch rotor or propeller - like a cppm
helicopter. it is not applicable for a multirotor. ( at least not your one)

Oh I didn't know that ! But I think I saw some videos where people have been changing the pitch curve for multirotors. I'd double check what its all about.

By the way, any idea why till 50% throttle my quad does not gain significant height? And only after 50% it begins to rise higher? Do I need to adjust throttle curve or something? Or could there be other reasons? I have a CX-20 and a Syma X5C-1 and in both cases the quad gains significant acceleration upwards even before reaching 50% throttle.

@santanucus

I guess you know this, but an APM multi-rotor is sopposed to achieve a stable hover at 50% throttle. If your quad hovers above (or below) 50% throttle you need to decrease (or increase) the 'throttle_mid' parameter. Don't change the throttle curve on your transmitter.

Try this, if you haven't already:
http://copter.ardupilot.com/wiki/ac_throttlemid/

Using pitch and roll curves makes the quad less sensitive around the middle stick position. This helps while landing or trying to get a stable hover.

Thanks @swapnil. Yes...I had read about the stable hover at 50% throttle level. But before this I have mostly flown RTF quads which had good throttle response much below 50%(say around 30%) . In fact in some of those quads when the throttle reached 50-60% and still the quad was only hovering, it meant that battery had almost depleted. That's why, when in this quad I have to go to 50% for stable hover, I feel uneasy Anyway, I did not know that throttle_mid parameter could adjust this property. I Will try that out.