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pluckas
Posts: 104
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Hello all,

I've had good success programming MobiFlight with prototype MCP switches, segment displays and rotary encoders with PMDG 737 offsets and events, but I'm really stuck on how to get a servo driven flap gauge working. My best effort still results in erratic motion, despite trying a number of things found in forum posts and elsewhere. For what it's worth I'm using the SISMO flap gauge - a conventional servo driven affair.

I think I need some really basic help with this - and apologies if its been covered before (I've tried the tutorials and posts without success).

Thanks in advance,

Paul
2018-10-02 10:59
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pizman82
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From: ETSI, Germany
Posts: 4988
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Hi.
Please use SARCH Function..... choose the "advanced" Checkmark and only choose the PMDG Subforum !
Then Search for the word "Flaps" .
You will find 5-10 Topics with lots of information !
Most of them are for Stepper instead Servo Motors.... cause the Stepper is more comfortable for this gauge ( 95% of users have stepper here i think)
BUT The basic technics are identical and will work for Servo, too.

Important.... Check out the "Decimal Value" Problem i explane multiple times in this topics. You must multiply the PMDG Flaps Value to get a smoothe running needle !
Also check out the DOUBLE Offset,,,, PMDG have a Offset for LEFT and a other offset for the RIGHT Flaps Needle !

So please search for that,,,, If you have already a problem after study this then ask me here in this topic again !
Good Luck !
2018-10-02 17:22
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pluckas
Posts: 104
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Thanks.

I've made some progress experimenting with transforms and interpolation settings, though I'm not quite sure why some users are choosing multipliers of 100 versus 1000, as well as the variety of max values quoted in the posts I've read.

But it's almost working - and now I'm trying to 'tidy up' the short comings of using a servo for this.

In this post - https://www.mobiflight.com/forum/topic/191.html - there's mention of a rounding function to help zero the needle. Unfortunately the solution has not been detailed, and my knowledge of the syntax is poor. Any help gratefully received.

Paul
2018-10-02 18:12
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pizman82
Moderator
From: ETSI, Germany
Posts: 4988
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This is a real old topic from 2015 :-)

Basicly the user do a technic that was a bit unconventional .
With his transform the ROUND Function was maby needed.... But i think this is finaly not needed and to much confusing.

For the Flaps Gauge you MUST use Interpolation ( Cause the gauge is non linear ) . So if you already use the Interpoaltion Tab you can also set here the Servo Starting Position if it is realy need for your Gauge.

Please simply use the guide i explane a lot of time.
You should use the "TEST" function in the "Device - Servo Tab" Of Mobiflight.
For example you say MIN = 0 MAX = 1000 ..... then use for "TEST" Value for example "100" . Check out WHERE the needle Stop.
If you have a gauge like the other user (Maby this SISMO stuff) where the Zero Point of Servo is BELOW the Zero Point of Gauge Label then you first need to find out WHAT Value is needed to get needle on ZERO Position.
Same is done for all other positions.... 1,2,5.10 and so on.... YOU must know every OUTPUT value that is need to get needle to correct posiiton.

Finaly you Mulitply the FSUIPC Value from PMDG by 100 or 1000 ( Both will work but 1000 is more smooth ) .... And in Interpolation field you will combine the Offset Values to the explored Points of your Servo ....
For example Flaps 0 means Config INPUT Value of 0 .... and it must interpolated to the value you find out before WHERE the needle is exact in Zero Position on Gauge.
In next line you say Flaps 1 means Config INPUT Value of 1000 and it must interpolated to the value you find out for Flaps1 Position on your Gauge !

If you enter all the Steps in the interpolation field then your Servo will work 100% correct i think !
Good Luck !
2018-10-02 22:54
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pluckas
Posts: 104
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Thanks again for your help. I've had no luck - the servo does not reliably return to the same position in tests, and there is evidence of "servo creep".

I think modifying this unit to take a stepper motor is in my future.

Paul
2018-10-03 02:05
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pizman82
Moderator
From: ETSI, Germany
Posts: 4988
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Sad to hear it not help directly....

I agree. A Stepper Motor is mostly the better choice. Sure it occure in some "electrical problems" cause a stepper need a lot of Power So you should think about a External Power tool if you need more Motors on ONE Mega or you should plan your Setup so on the "Motor Megas" there are not too much other Outputs like LED and better more Inputs that need no power...... But summary For me a Stepper is normaly always the more comfortable choise.

Last note about Problem.

If your Servo not return to correct positions then it is maby alredy broke If you test it and it overturn in case of wrong settings while testrun the servo can alreday be destroid totaly.
Other fact is the gauge.... Maby it have a internal gear to work with a 180° Standard Stepper. "Maby" This gear is Broke !

Check this "hardware" facts. Also think about if you can use a stepper for that gauge ( internal gear ??) Simply open it (withoud destroy it) and check the mechanic !
Good Luck !
2018-10-03 06:23
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