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Message #25774

kjoussen

From: Hamburg, Germany

Posts: 178

Hi there,

in my project (motorized trim wheel) i have two servos.

1: one self-made with a geared motor and a 10-turn poti, both connected to a servo electronic
2: one standard 9g servo

Whereas No 1 can make 8 full rotations (like the trim wheel in an Airbus), No 2 makes only a half rotation.
So, in the end both are showing the same, one showing the pilot that the trim is "on its way" and the other - the indicator - at which level the elevator trim is.

Therefore both are feeded by FSUIPC Offset 0x0BC2.

So far so good, and the two Output values for the Servos in the MF-Gui are equal.

But most of the times the small 9G Servo is fidgeting, yes rattling back and forth a little, as there would be a fast changing value coming non stop, which is not.

I already changed the servo but the same.

Funny enough, when going on the Display Tab - TEST (Values are 0 / 255 / 100%) the same happens.
The servo "jumps back and forth a little. As soon as i put my finger on it: tuie.

Ah....don't have a clue.

Thanks

Kai

2022-04-12 14:06

Message #25776

pizman82

Moderator

From: ETSI, Germany

Posts: 6010

Supporter

You already start the process i would do.....

Step 1. Use another Servo if available. (Still done)
Step 2. Use another Pin for the second Servo. Maybe there is a bad connection on that one. Also choose for a other Pin Typ. If you use Analog a.t.m. use a DigIO.
Step 3 Change Wirework Maybe Cable is broke.

In easy words...
Try to split it.... Check Wirework, Pin, Mega and Motor best way seperate. Hopefully one of the 4 is the "bad boy".

Good Luck !

2022-04-12 17:14

Message #25779

kjoussen

From: Hamburg, Germany

Posts: 178

Got it sorted out

Nor is it the servo, pin, cable, wiring....it is the weight of the part the servo has to move / turn.

The indicator ring shown in the picture is a 3D-printed part and has a weight of only 38g, but the axis around it is turned is horizontal, obviously the servo has some trouble with it.
I knew that the SG90-servos are weak...but such a wimp?

Well, then i will replace it with a 3 or 5kg servo.

2022-04-13 09:57

Message #25827

Whiteknuckle157

From: Bayern - Bibertal, Germany

Posts: 50

Hi,

the SG90 is rated between 1.6 and 2.3 kg/cm. That should be sufficient.
Do your servos have a separate (5V or 6V) power supply?

cheers

Volker

2022-04-20 20:28

Message #25835

kjoussen

From: Hamburg, Germany

Posts: 178

Yes, i also tried with external power but no changes.

As soon as i turn the servo on its back that the indicator ring lies "horizontal" it is moving without problems.

But in the trim box the indicator ring stands vertically and then my Mini-9G-Servo (plastic gear inside) is wobbling like mad.

With the 3kg servo without(!) external power everything is fine now.

Kai

2022-04-21 21:32