Question about servo activation

[mauriceb]

Hi Alan,

I'm wondering if you can shed some light into the behaviour of the servos and your flight sim software. My understanding is that if there is no signal on the control wire in the interface, the servos should not move at all even if power is applied to them. With that in mind, I designed a logic circuit which turns a relay on to provide power to the servos whenever the autothrottle is turned on. At other times, the relay is turned off and no power goes to the servos.

Yesterday, while testing this, I kept seeing the servos react 'violently' just when power was applied and even when the servo cable was not attached to the servo interface card; in other words, just 6V was applied to the servos & nothing else.

After much fiddling around, I eventually got everything working OK, but I have no idea why it is working now and why it acted up earlier. I'm concerned now that this may happen to me again when I'm just taking off and switching on the A/T and having the servos (& throttles) go nuts on me .
If you have any idea about what may have caused that, I would really appreciate your input.
Thanks,
Maurice

PS. Your software is simply amazing. I'm also using your FS Value Rate of Change with the Elevator_Trim_Indicator offset to control some DC motors for the trim wheels (with a logic circuit I designed) and this is working great.
Thanks for a great piece of software.

[alandyer]

Maurice,

You're speaking to the wrong fella.
I'm no servo expert.
Pretty sure someone out there on forum has encountered a similair problem.
I'm curious as to the reason for the same reason you are.


Regards,
Alan.

[mauriceb]

Maurice,

You're speaking to the wrong fella.
I'm no servo expert.
Pretty sure someone out there on forum has encountered a similair problem.
I'm curious as to the reason for the same reason you are.


Regards,
Alan.

I took a wild guess by addressing this to you since you wrote the software that controls the servos & many other things in FS. I though you might have encountered that issue at some time . As you said, I'm pretty sure as well I'm not the first one having experienced strange servo behaviour and I hope someone else can share their experiences.

Thanks again for having written & shared that great software. A few months ago, I would never have believed that I could build a throttle assembly with a functional A/T and all the other functions while using a simple but very sophisticated graphical user interface. That made life so much easier for me and I'm sure countless others as well.

Best regards,
Maurice