Servos not moving on Servo Test , why?

[almarton]

Hi all,

I have an EFIS D100 firmware 5.1.0 (from factory) wired to an AP74 and SV32 servos, wired correctly to the extent of my knowledge (checked twice). I am not sure but I believe the DSAB network (servos and AP74) was updated itself automatically to the EFIS firmware when on. Is that right?

I performed DSAB configuration following page 6-13 of the manual
but during the Servo Calibration & Initial Servo Test it DOES NOT move full range when connected to the aircraft command surfaces.

Instead it starts and promptly gives a clank sound and stop almost without moving.

The calibration was successful and when I disconnect the servo from the surface it does move… What would be the main reasons for that (not moving when linked to the control surface rod)? (I did configured airspeed color thresholds).

I do believe that I adjusted the slip torque to the max. Would it be that the installation of the linkage mount position is not providing enough force to counter the weight of the command surface?

Another question, When the AP indicates AP-CWS should the stick be stiff and hard to move? What is feeling in the stick is expected when in AP-CWS mode?

I hope I made myself clear… I am very frustrated having my brand new Aircraft, EFIS and AP and not being able to put it to work. Embarrassed

Please help, many thanks in advance.
Alexandre Marton

 

[almarton]

Hi again!

What is happening to me is pretty much what happened to the fellow on this post:

http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1226713787/0

The difference is that mine only moves a bit in one direction when servo test stars with the stick off center, with stick centered it does not move at all only jitters and clicks.

Was that problem solved for the original poster off this topic?

I would aprecciate any help or feedback on that...

DYNON SUPPORT please help!?! Any advices, tests and checks I should do? Move the rod through the servo arm location holes? :-X

 

[almarton]

I am refusing to do fly servo test when ground test is not moving right but I read this post:

http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1252581640/1#1

DYNON SUPPORT would that make sense? I mean, SV32s not moving in servo test but perfoming correctly in flight? Should I try?

Please any help , tips, checks , suggestions... Thanks in advance.
Alex.

 

[almarton]

One last thing, I linked the EFIS D-100 with the Garmin 296 GPS through one wire on the data cable... would that affect in anyway the servo test I described above ?

I did not notice either if the EFIS recognises and receives data from the GPS yet... how do I chek if the connection between then is ok?

My main concern is the autopilot and servos though...

Thanks.

 

[dynonsupport]

First, what kind of aircraft is this?

When in CWS mode, the autopilot is not engaged, so you should only feel the minimal residual drag of the servos. They are basically powered off. It should not be hard to move the stick.

The servo test does not move the servos to the extremes that you've shown the autopilot. It moves the servos a portion of the way in each direction to confirm that the servos can be moved. In other words, it should be a perceptible move.

Are both your servos doing this? If you disconnect the servos from the control system and do a servo test, do they move then? If so, it sounds like something in your linkage is too tight and preventing movement, or, if the control surface really is that heavy (common in cubs, not common in RVs), it's possible that you need a higher torque servo.

All that said, if it's flying the airplane well, the results of the servo test do not really matter.

Having the GPS connected does not affect the servo test.

 

[almarton]

First thanks for the reply Dynon!

Well the aircraft I installed the servos and AP74 is a PATRIOT 150 LSA link below:

http://www.silverskyaviation.com/pages/patriot150.html

During Servo Test the servos were not moving at all (just jitters, clicks and clank sounds when I start test with stick off center ). Both servos doing only that.

Tomorrow (Saturday) I will disconnect the servos from the control system and check for you.

Besides thar:

Someone suggested in other threads that I should verify/try:

a) put the rod end on the inner most arm location (more torque);
b) verify if the servo arm is perpendicular to the rod when in the center;
c) verify if I have the 'disconnect' switch - check that it IS a 'normally open' MOM type. Because they (jakej) say that: “…If it is a 'normally closed' one you can complete the calibration BUT the servos won't move when final system test is done…”

That makes me ask to you Dynon Support and all you fellows that glad to opine:

1) When doing calibration and the screen says: “Press disconnect switch to finish” - I wonder if the disconnect switch was a “normally closed” (like Jakej suggested) would the screen still be asking for pressing it to finish even it is at a “pressed state”? Cause the calibration only finishes when I press the disconnect switch, if it was closed (pressed) wouldn’t it be finished automatically without having to wait for me to press it?

2) AP does look to be in CWS mode, the autopilot is not engaged, because I only feel the minimal residual drag of the servos.

If I engage AP on ground would I feel big drag on the stick?

Well I will try those suggestions on this Saturday (tomorrow) and post here the results or any development on the situation.

Thanks everyone for the help and any suggestions that I still could use tomorrow please post.

Regards;
Alex.

 

[dynonsupport]

If you're seeing CWS and you're not holding down the button, then it sounds like your disconnect button is grounding it when it's not held down. This is the opposite of what you want, so look into that problem first.

 

[jakej]

c) verify if I have the 'disconnect' switch - check that it IS a 'normally open' MOM type. Because they (jakej) say that: “…If it is a 'normally closed' one you can complete the calibration BUT the servos won't move when final system test is done…”

Alex

The MOM switch issue happened to me because someone 'borrowed' a PTT switch from me a replaced it (accidently I'm sure) with the NC type - I never have those in my parts inventory. Goes to show you can get caught out

Jake J

 

[almarton]

Hello, all.

First things firts.

- the disconnect switch was a normally closed one, so I did not replaced it.

The AP passed on Servo Test now... now it is moving the stick a lot in the expected directions. It is also making the stick hard when I on ground engage the AP on HDG function.

But I am not sure what I did to fix it, I think it has to do with the servo arm that was not perpendicular to the command rod when stick was centered, I fixed it and the servo test went well.

I could not fly test it yet due to horrible wheather that prevented me to flight during all this weekend, but I will fly as soon as possible and post results and impressions here.

I still have a minor problem and a few questions if you could help I appreciate also.

1) How do I engage de CWS function, what does this CWS is supposed to do? Either I could not understand by the manual (my poor english I think) or I understood the manual but CWS is not behaving as such (on ground)

2) My GPS (Garmin 296) was hooked to the com 1 EFIS throug the Garmin provided data cable (1 wire), but sometimes on HSI I see a GPS warning (don't remember what it says) but only sometimes most of the time GPS does not appears on HSI, any ideas on what is happening? By the way I did set Aviation In/Nmea out on GPS com 1...

I would like to thank the suggestions and support.
Thanks, thanks thanks
Alex.

 

[almarton]

Hi!

I made the AP test fly and all went well!!!!! Nice! very happy with it Dynon.

I configured the HSI serial com and got input from GPS Garmim 296 on the HSI BUT... still not able to execute AP74 NAV function, on test flight the only modes that worked were HDG and ALT.

Anyone knows if there is some configuration or buttons to press prior to engage NAV on AP74? (the gps had a go to set already)

And I still don't know how do I engage de CWS function or what does this CWS is supposed to do? Either I could not understand by the manual (my poor english I think) or I understood the manual but CWS is not behaving as such (on ground)

Hope to have a reply from support soon because I read and read the manual and did not understood the english explanations for those.

Thanks
Alex.

 

[dynonsupport]

Alex,

Please try not to post the same questions in multiple threads. It makes it hard for us to track your issues. We'll respond to your NAV issues in the thread you opened about that topic.

CWS basically lets you temporarily control the aircraft while you hold the disconnect switch. When you release, the autopilot resumes control of the aircraft. You can also engage the autopilot when it is not already engaged by pressing and holding the disconnect switch. When you do this, you will see the CWS message as well to let you know that when you release the button, the autopilot will engage on the axes that you see CWS on.

 

[jakej]

"First things firts.

- the disconnect switch was a normally closed one, so I did not replaced it."

Hi Alex,

Your comment above - the switch has to be a normally open (N.O.) type. ie when you press it, it makes contact. Not sure if you understood that

Jake J

 

[almarton]

Hi Jake, indeed I wrote normally closed but I meant normally open, fact is I did not need to replace it to make the AP work as it is working today.

My only problem now is to access NAV function on AP74, it does not engage the button does not come lit when pressed.

I think it has something to do with GPS baud rate, I will try to set EFIS to auto baud rate and GPS 296 to 4800 baud rate, cause now using EFIS AUTO and 296 on 9600 baud rate I see GPS data on HSI but I still can't engage NAV.

Thanks!

 

[rvator51]

Make sure your GPS advanced interface is set to 'Normal". If it is set to "Fast", you wont be able to use the "Nav" function.

When you are in setup and in the tab when you set the baud rate and interface type, press the MENU button once to bring up the advanced screen to see whether your gps in in Fast or Normal mode.
Regards,
Tom