Servo Power for throttles

[imported_redman]

Hi there,
just a question on powering my servos.
I am hooking up three 815BB servors to power my throttle and speedbrake handles.
I will be wiring the red wires from the servo directly to a power supply, with the black wires going to both power supply and the phidget card (which also gets the white control wire)
I am trying to find a variable power supply as mentioned in the auto-throttle tutorial.
Can anyone confirm that it is a 8 Amp 4.8-6VDC source?
I am having trouble finding something with that many Amps. Will something outputting only 1000mAmps burn out?

thanks
Chris

[mauriceb]

I am trying to find a variable power supply as mentioned in the auto-throttle tutorial.
Can anyone confirm that it is a 8 Amp 4.8-6VDC source?
I am having trouble finding something with that many Amps. Will something outputting only 1000mAmps burn out?

thanks
Chris

8 AMP is way too much for this, but 1000mA (1 A) is likely not enough. I had trouble finding a 6V power supply, so I used 2 X 6V-1.5A power supplies that Phidgets sell for their interface cards and I connected the output wires in parallel together (watch the polarity) so that the output amps add up to 3 Amps. This is more than enough for my 3 servos especially since the speed brake only comes on after landing.

A 5V- 2 to 3A power supply would also work depending on how much friction you have in your throttles. If they are fairly loose, it will work fine (that's what I used during the construction & testing phase of my throttle).

Hope this helps,
Maurice
ps. It does not have to be a variable power supply

[imported_redman]

Thanks Maurice,
Now comes the fun part.
I have a question regarding the implementation of the speed brake lever with a servo.
From your web site you describe having additional circuits to only use the servo when on the ground, and armed.
I am tryng to get my head around what i need to do for this.
Does this mean you do not use FS2phidgets to control this function? How did you program/setup this logic? What additional hardware/wiring was needed? (i am still learning about wiring and components, so a bit of a newbie in this area)

I looked at FS2 and saw there was a speedbrake hanldle variable, but this tracked movement all the time.

Has anyone else implemented a servo on the speedbralke handle?

Thanks
Chris

[mauriceb]

I looked at FS2 and saw there was a speedbrake hanldle variable, but this tracked movement all the time.
Thanks
Chris

Exactly. If you have a potentiometer controlling the speedbrake, that potentiometer is always 'active' in FS? as opposed to the way the throttle behaves in FS?. When the autothrottle is on, FS9 ignores any inputs from the potentiometers that are attached to the throttle handles.

That's why I found you have to disable the spoiler servo when in flight. Otherwise you get conflicting inputs to the servo & I had found that at times, my spoiler handle was going nuts & swinging all over the place. Besides, you cannot move the spoiler handle if the servo is active anyway.

So you have to disable the servo one way or another when in flight, either via software commands (which I don't know how to do with the Phidgets software), or by removing the power to the servo which is fairly easy to do.

The circuit you saw simply disconnects the power to the servo unless the spoilers are armed and the plane touches down. At that point, you are not moving the handle. FS9 is & does that by changing the variable and that same variable makes the servo move the handle to the fully extended position.

After you re-apply the power, FS9 again is in control and retracts the spoilers automatically like in the case of an aborted landing for instance (you don't have time to think about retracting the spoilers manually). Once the spoiler handle is back in the home position, I simply used a switch the disable the power to the servo again.

I'm sure there are probably better & more 'elegant' ways of doing this, but this works for me.

Hope this helps,
Maurice

[imported_redman]

...by removing the power to the servo which is fairly easy to do.
I simply used a switch the disable the power to the servo again.


Hi Maurice,
If I read this correctly, are you using a hard wired switch that you turn on after arming the spoilers, which then will send power to the servo ?

Are you using ps2phidgets to control your servos? With your logic for auto throttles (i.e autothrottle on plus other state) is this done through fs2phidgets or something else?

Like the speedbrke, I can't seem to see anywhere to add logic to the phidget control (i.e. an if/then type of logic).

Thanks again.
Chris

[alandyer]

Gentlemen,

How about I add a software setting to inhibit servo when spoiler is armed ?

i.e. user can choose an fs variable ( or variables ) to use as the inhibiter.
In case of the spoiler,
would the inhibit variable be Spolier Armed ( offset BCC ) ?

Shoot me a PM and we can work a solution.

Regards,
Alan

[mauriceb]

Gentlemen,

How about I add a software setting to inhibit servo when spoiler is armed ?
Regards,
Alan

Hi Alan,

Actually, the reverse should be true. You don't want to inhibit the servo when the spoiler is armed, otherwise it would never deploy after landing. But even if you used the reverse logic and enabled the servo when the spoiler is armed, that would not help either.

From what I have seen, the spoiler armed indicator does not just stay on only when the spoiler handle is in the ARM position, but also after it has deployed after landing and also at other times. It shouldn't but it does at times and I don't understand why.

My experience with the 'arm' offset has been that you can't rely on it except when you arm it before landing. After landing, it behaves erratically (in my experience anyway). That's why I had to find an alternate way to handle the spoilers.

So, thanks a lot for offering a possible solution, but at least in my case, that would not resolve the issues I had with the spoilers. I did manage to design a roundabout way to handle it with some additional logic as you can see in my schematic in the link below if you are interested.

Best regards,
Maurice

http://thumb0.webshots.net/t/46/47/8/22/29/2346822290051510320rqZKXq_th.jpg (http://entertainment.webshots.com/photo/2346822290051510320rqZKXq)

[mauriceb]

Chris,
See my comments in red below:

If I read this correctly, are you using a hard wired switch that you turn on after arming the spoilers, which then will send power to the servo ?

No, not at all. The hard wired switch is just to remove power to the spoiler servo; you do not physically actuate the switch...it is actuated by the spoiler handle when the spoiler retracts (see schematic & explanation below)

Are you using ps2phidgets to control your servos? Yes With your logic for auto throttles (i.e autothrottle on plus other state) is this done through fs2phidgets or something else? Combination of Phidgets + my own logic circuits

Like the speedbrke, I can't seem to see anywhere to add logic to the phidget control (i.e. an if/then type of logic). That's why I had to design my own circuits

Regards,
Maurice

http://thumb0.webshots.net/t/46/47/8/22/29/2346822290051510320rqZKXq_th.jpg (http://entertainment.webshots.com/photo/2346822290051510320rqZKXq)

[imported_redman]

Maurice / Alan,
I think i am getting there (both mentally and physically!) :)
I will use fs2phidgets to control movement of throttles, and speedbrake lever.
The ground of the power for these servos will be sent through a 0/16/16 board.
the LevelD 767 has autothrottle status (i.e. 0=OFF, 1=ARMED,3=SPD, 4=N1, 5= FLCH, 9=FAIL, etc), so through FSCONV and SIOC i can write a logical if statement that will write an offset ($8BFF) bit to 1 if the autothrottle status is >1 and <9.
I can set fs2Phidgets to open the 0/16/16 digital output when this is true, thus powering the servos.

Same for the speed brake (i will write a offset to 1, when on the ground, >60kts and level is armed, and will have is reset back to 0 when spoiler is DOWN)

Just have to make sure that the 0/16/16 card can handle the power of the two wired power supplies.

Hope this makes sense / will work. Any comments?

Thanks again

Chris

[mauriceb]

Sorry but I don't really understand what you are doing, so the only thing I can add is that the autothrottle switch is not the only thing that determines whether the servos should be activated. You also need another input to be active such as TOGA or Speed switches. The A/T switch is really an A/T ARM switch & not A/T activate.

Maurice

[alandyer]

James,

Here is a solution I am working on with fs2phidget.
Those large servos for the speed brake and auto-throttles require a power controller i.e. relay.

I am proposing adding a "Servo Control" setting for digital output that controls 0/0/4 relay.
This setting will consist of a list, of up to 8 offsets, (that the builder can assign,) that must ALL be at a specified value to turn the digital output on. This will replicate AND gate circuitry.

Henceforth, called M-control in honor of builder who perfected solution.

In addition, by assigning the speed brake servo and speed brake sensor (pot) to the same fs2phidget virtual circuit, the sensor can be inhibited when the servo is active, and vica versa.

There will also be a value setting for the sensor, that will indicate when sensor is to turn the digital output off (or on). This emulates switch on the spoiler lever.

Maurice,
Refresh my memory, how many conditions do you AND together on your auto-throttle servo controller ? Are 8 offsets enough ?

Regards,
Alan.

[mauriceb]

Maurice,
Refresh my memory, how many conditions do you AND together on your auto-throttle servo controller ? Are 8 offsets enough ?

Regards,
Alan.

Hi Alan,

This is great news, but I wish I had asked you to do that before I completed mine :) . But I'm not 100% sure I fully understand your solution. Basically, I use only 2 inputs to an AND gate (the output powers the relay); one of them is the A/T ARM offset and the other is the output of an OR gate. The OR gate generates a true output (1) if either of 3 conditions are true - Speed, TOGA or VNAV. If using FS9 without PM MCP software, the offsets inputs to the OR gate are different and for sure you will also need the MACH offset in addition to the SPEED offset. With PM, I don't need that one.

Now, getting back to your solution, if you are able to replicate the AND/OR conditions (I'm pretty sure you can) then 8 offsets are more than enough. I only use 4 now, but I'm pretty sure there might be additional offsets which I haven't thought about yet and which may be needed under some other condition when you would want to enable the servos, so I left unused inputs in my OR gate to take care of those. if needed. So, your 8 inputs should take care of just about everything I would imagine.

I wish the 0/0/4 had been available when I needed it. It was back-ordered for a long time and it is such an easy way to actuate a relay instead of using discrete components.

Anyway, I think your solution is going to make a lot of builders very happy. It will be a very elegant way to deal with this thorny issue. Feel free to ask me any questions about my klutzy, but working solution if you need to. ;)


Best regards,
Maurice

[imported_redman]

Hi Alan,
thats great news. Thanks.

Would a circuit throught a 0/16/16 also work for this? (i.e. any reason for using a 0/4/4 instead)?

Regards
Chris

[alandyer]

James,

First part of your question:
From a logical standpoint, digital output is digital output.
Fs2Phidget applies same digital functionality to any output: 0/16/16, 0/0/4, 8/8/8, 1/0/256, 0/32/32 or LED-64

Last part of your question:
Will card handle voltage and amperage ?
The 0/16/16 literature states:
Digital outputs can be used to drive LEDs, solid state relays, transistors; they can sink up to 30V at 2A.
Maurice, or better still, the folks at Phidgets Inc, are better persons to answer this portion of your question.

Regards,
Alan

[imported_redman]

Hi Alan,
thinking about it, the 0/16/16 uses shared voltage, but the 0/0/4 relays uses seperate circuits for each output, so they can be seperated.
I have oreder a new 0/0/4 and look forward to the new functionality when available.

Cheers and awesome thanks.
Chris

[alandyer]

Chris,

Keep calling you James. Apologies.
One other design consideration:
B737 throttle quadrants have a solid detent at the Spoiler handle's DWN position. Requires lifting handle to move out of detent.

If you have quadrant that has this detent,
you may want to consider a cut-out switch, as in Maurice's design.
Servo may get into a fight with handle in the detent position and loose.

Regards,
Alan.

[alandyer]

Have an update on fs2Phidget for spoiler handle servo.
Tested yesterday evening with ePhidgets.
Testing today against real servos.
The solution is generic, i.e. intention is also to use for auto-throttles.

Assumptions:
A digital output, usually a 0/0/4, controls power to large servos.
Analog input senses spoiler position.
Servo moves spoiler handle to UP or DWN position.
Analog input and servo connected to same handle.
A digital input senses state of a Cut-Out switch at the spoiler handle DWN position.
OEM throttle quads have detent for spoiler handle DWN position.
Would not want servo attempting to move detented handle.
Servo might loose the battle. (I love the smell of servos in the morning)

Configuring:
Assign Spoiler_Handle variable to Digital Output (0/0/4 controller), Servo, Analog Input and Digital Input (cut-out).
Assign above to same Circuit.
Select configure for Digital Output.
A "Servo Power Control" button will be enabled if a servo and an analog input are attached and have been assigned the same circuit and the same variable.
Press button to configure "Servo Power Control".
Configure by selecting (up to 8) variables that specify condition when servo is enabled.
In case of spoiler this would be Spoiler_Armed and Squat_Switch variables.

Operation:
The configured variables values are compared to their On Values.
If both variables are "On" (logical AND) the servo is set "Active".
(for example, if Squat_ Switch AND Spoiler_Armed are ON )
the Servo-Controller Digital Output does the following:

Goes On or Off - connecting or disconnecting power to the servo.
Sets Servo to "Active" (receives updates on spoiler handle position).
Sets Analog Input to "Inhibit" (does not update spoiler handle position in MS-FS)
If Cut-Out is detected "On" - Servo is inhibited and Sensor is activated.
Inhibits Cut-Out digital input state from updating the MS-FS' spoiler handle position.

[imported_redman]

Awesome work Alan,
I hopefully will get my 0/0/4 soon, and will be ready to give it a try.

Thanks for your hard work.

Cheers
Chris

[JW&Partner]

Hi,

attached you find a possible solution for the throttle with phidgets and 4 low cost low current relais.

http://shop.strato.de/WebRoot/Store/Shops/15465782/452F/7E59/D3C6/9ABF/E4F3/C0A8/30C1/2E4D/Verkabelung.doc

kind regards Jörg

[garyk007]

Sorry to resurrect old threads, but I read these 2 pages 3 times and am still a bit confused.

If I buy the phidget usb servo 4 contoller, do I also need to buy the 8/8/8 card?

I am testing the opencockpits cards for switches/leds etc.

I will be buying the simparts TQ kit as soon as they are back up and running.

So what parts, cards do I need to buy?

Also will a micro switch work to disconnect the power to the speed break servo? or do I realy need a relay?
If so which type and can some one give me a brief explanation of how they work and how to connect them?

Also which servos are recommended?

Thanks