Autothrottles

[firstinflight]

I got my Phidgets Servo Controller today with 4 servos.
I connected it to FS 2004 via FS2Phidgets.

The servos operate fine and track the throttle fine.
Was looking to find solutions to free up the levers when A/T is OFF or when A/T may be armed but SPEED is OFF.

Question 1 - How does one do that? I saw one way to do it was to use relays? How does one wire a relay to the servos?

Question 2 - I see some posts on using power supplies to power up the servos directly? Rob's writeup talks of simply plugging in the servos to the card. Thats what i did. So where is the need to wire the red to the power supply and the black to both the supply and card and so on...?

And finally - is there any other way of disconnecting the servos via an FS variable such as A/T Disarm?

Thanks in advance.

Best regards,
CPJ

[Daveanne]

This was the way I did it, with lots of help from Peter Dowson and a Mr Roper?

http://www.mycockpit.org/forums/showthread.php?t=14662

Daveanne

[firstinflight]

Daveanne:
I read through that whole thread. I followed all of it but i couldnt see where it talks about servo disconnects.

Based on Rob Howard's article i plugged in the servos directly to the phidgets board and it works fine.

I also see Alan Dyer's post where he says that now we can disconnect power to the servos based on logic variables instead of having to hard wire the power through a relay or switch. But as much as i have tried with circuits i cannot get my servos to disconnect based on the A/T ARM offset.

All i am trying to do is that i want my TQ handles to be free for manual movement when the A/T offset is 0 and servos active when A/T offset is 1.

Any help will be much appreciated.

Thanks in advance.

CPJ

[Daveanne]

The way I did it was to buy the 0/0/4 relay board from Phidgets, use the FS2phidgets programme, available on this web site for download and configuer the A/T and A/P switches to operate the relays.

Therefore when the A/T is engaged along with the A/P (CMD A), then a live feed is placed to the servo's.

This enables you to use the throttles by hand when taxi-ing, and or in flight, switch the A/T off for manual throttle control, when finished select A/T again and they are back under the control of the A/P.

Daveanne

[mauriceb]

Therefore when the A/T is engaged along with the A/P (CMD A), then a live feed is placed to the servo's.

This enables you to use the throttles by hand when taxi-ing, and or in flight, switch the A/T off for manual throttle control, when finished select A/T again and they are back under the control of the A/P.

Daveanne

This isn't really the way the A/T should operate. You should be able to have the A/T on without the A/P being on as well. The two are totally independent of each other and the A/T should only come on when the A/T switch is armed and any of the MCP speed modes are active such as IAS/MACH, VNAV or N1 for instance.

This way, you can still fly the plane manually but not worry about throttle setting if you choose, and that's the way the real planes operate (at least the Boeing airplanes anyway... no idea how Airbuses do it)

Maurice

[kalz]

I have set up the logic in FS Var editor such that (using default 737 in fs)
when autothrottle arm = true and
autopilot master switch = true
then the 0/0/4 relay is on, however servo doesn't move.

I have noticed though,when the
autothrottle arm = false and
autopilot master switch = true then the servo does move
and when
autothrottle arm = false and
autopilot master switch = false servo also moves.

Help appreciated as always.

[mauriceb]

I have set up the logic in FS Var editor such that (using default 737 in fs)
when autothrottle arm = true and
autopilot master switch = true
then the 0/0/4 relay is on, however servo doesn't move.



Once again, A/P & A/T are independent in a Boeing airplane, and that's why you get the above result, which actually is the correct result...autothrottle arm=true & A/P switch on should not allow servos to operate. A/P can be on or off, but the A/T will/should only work when autothrottle arm = true & any of the MCP speed modes are engaged as I said in my previous post.

Maurice

[firstinflight]

Okay I get the logic. And i agree with Maurice. That is how i have setup my logic variables.

But back to my original question about what Alan Dyer meant when (this is what i interpret it to be) - he said the following -
[QUOTE]we can control the servos based on logic variables instead of having to hard wire the power through a relay or switch.[\QUOTE]

In fact, Maurice you may remember - you responded to him by joking about "where were you when i needed you... ".

Further, I WAS ABLE to create a logic variable and assign it to a Emulator Digital Output and also assign it to Circuit 1.

I assigned a servo to Engine Throttle 1 and to the same circuit.

And with this setup i WAS successful in getting the logic variable to control whether the servos responded to FS2P or not. When the logic variable turned TRUE, the servos began to respond to FS2P. BUT WHAT I COULDNT GET TO HAPPEN was that even the servos stopped responding to FS2P based on that logic variable - i.e. when it turned FALSE - they will still powered and hence couldnt be moved by hand (manually i mean).

Which tells me that while logic variables and circuits CAN be used to control whether a servo responds to FS2P or not, they STILL CANNOT be used to disconnect power to the servo.

Which then further tells me that we will still need a relay (0/0/4) card to control power to servos

AM I UNDERSTANDING THIS CORRECTLY? Is there NO way to control power to the servo other than hardwiring it through a relay?

What confused me is an earlier post on this subject and also the HELP file on FS2P which says that we can use logic variables and circuits to do what Maurice did via hardware. The help file goes to say in the circuits section where the servo control example is given that this can be accomplished 'with or without 0/0/4.

Another point - I am NOT using a phidgets card for input. My inputs go in via Leo Bodnar BUxxxx card. I dont think that should matter though but didnt want to leave it out of this post.

Best regards,
CPJ


Please help me to understand this correctly.

[mauriceb]

In fact, Maurice you may remember - you responded to him by joking about "where were you when i needed you... ".


When I started building my 737 throttle almost four years ago, I believe I was one of the first if not the first to motorize a homebuilt 737 TQ (I had my inspiration from the great tutorial about a motorized 747 TQ written by Rob Howard & available in the download section I believe) & there was much less help available and I did it the hard way.

So I do remember saying that to Alan when he came up with a new more versatile version of his software. But what I was referring to when I said that was the logic functions which would have allowed me to use the software to control the relay power instead of the discrete components such as resistors, transistors & logic gates I used in my circuit.

Although I haven’t really followed the development of Alan’s software lately, I do believe that Alan is now working on a strictly software solution to this where a signal can be sent to the servo control wire which effectively disengages the servos and eliminates the need for a hardware solution incorporating relays to cut off the power.

All servos can be disengaged by the appropriate signal in the control wire, so this is definitely possible, but you need the right software to do that and I don’t think that Alan’s software is yet able to do it (I certainly could be wrong, so maybe Alan can comment on this)

However, until that software solution is available, my logic circuit could be modified and instead of the discreet components I used, logic signals could be sent to the relays directly from the interface cards & Phidgets software and I would use the Dual Relay board instead of the 0/0/4 relay board that was mentioned since the dual relay board allows digital outputs from an interface card to activate the relays while the 0/0/4 board requires a USB connection & programming to actuate the relays.
http://www.phidgets.com/products.php?category=11&product_id=3051

If anyone is interested, here is my original circuit diagram. I would certainly not recommend anyone do it that way anymore, but the relay diagram could still be used if switching relay power on or off was still an option for you (using the dual relay board would work even better).

http://i32.photobucket.com/albums/d38/mau_ben/Throttleservoscircuitdiagram.jpg

And this is a link to my now antiquated throttle construction as there are now many much more elegant solutions from other very skilled builders:

http://home-and-garden.webshots.com/album/549398024hromFI?start=0

Maurice

[firstinflight]

Maurice:
Thanks for sharing.
I completely understand the context of your comment to Alan. I have seen your older posts on motorizing the TQ. In that post i was referring to, Alan brought up the point while responding to another post that one could now emulate what Maurice had done by using logic and circuits - in response to which you had made that comment. I totally understand. I read that whole thread and Alan and you have gone on to speak about trailblazing etc. Was interesting conversation.

I was holding off from buying the relay card and i now think that is a must. So will go ahead and order it. Unless i hear from Alan about this.

Alan - if you can respond as to whether servo disconnect is possible via software I will be sincerely grateful.
Once again, for your reference, i am successfully able to use a logic variable to control the servo from responding to FS2P. When i turn that logic variable true, the servo STOPS responding to FS2P. However even at that point they dont become completely 'free'. They are still powered and wont move freely.

What is it that i am not doing that will totally free up the servo? (other than of course using a hardware relay to disconnect power from the servo)

Best regards,
CPJ

[mauriceb]

I do believe Alan has already replied to your question in this thread:
http://www.mycockpit.org/forums/showthread.php?t=6828&highlight=autothrottle

If I understood it correctly, relays are still required now but he is or will be working on a software only solution. The current software already allows to release the servos when Phidgets exits, so this functionality exists but is not yet implemented to release the servos during flight as far as I can understand.

Hopefully Alan can sacrifice more weekends for the common good :-). But let's not try to rush him...he has already contributed so much for this hobby with his free software that I think he deserves a flight simulation monument named after him.

Maurice

[firstinflight]

Maurice:
You are correct. He does talk about my question in that post. I guess i missed reading it. Its a folly of reading many many posts at one time. One will miss important information.

Thanks for the info. That helped clarify in my head. I will wait for Alan to come out with his next version. I will also try using a toggle switch to break the servo circuit for now.

Best regards,
CPJ