Autothrottle datarefs

[jfjoubert]

Hi, would it be possible to add some datarefs for A/T logic in the not too distant future?

I've got some stepper motors and microcontrollers to build my own motorised throttle quadrant. All I need is to know when the A/T servos are engaged or not so that I can enable/disable my stepper motors. Currently I'm just checking the "ixeg/733/MCP/mcp_at_arm_ann" dataref to determine whether my steppers should be enabled or not, but this is a bit crude.

I think the servo disengage (whilst A/T is on) should really only happen when A/T mode goes into ARM, but there might be other modes I'm not aware of. Jan, your thoughts on this?
So maybe an "at_servos_engaged" dataref?

Thanks.
Jean

[737NUT]

I have AT automation working great in my sim, everything you need is already there now.  You know the 'ghost' handles that show up on left side of screen?  There is a dataref for those already and it's what I use.   And do yourself a huge favor!!!!!! Put clutches on on your setup. Do not direct drive the levers without protective devices.

Rob

[jfjoubert]

Hi Rob,

Thanks for the info... could you please provide me with the datarefs for the ghost throttles?

Thanks
Jean

[jfjoubert]

On 6/1/2017 at 3:09 PM, 737NUT said:

I have AT automation working great in my sim, everything you need is already there now.  You know the 'ghost' handles that show up on left side of screen?  There is a dataref for those already and it's what I use.   And do yourself a huge favor!!!!!! Put clutches on on your setup. Do not direct drive the levers without protective devices.

Rob

Hi Rob,

Could you please explain to me how you use this dataref to determine when to apply power to the autothrottle motors?

Thanks
Jean

[737NUT]

Compare the throttle handle's current position to the dataref desired position and determine if it is less or more and power motor in correct direction to null out the difference.  Cool thing is, when AT is not active, the handle position always matches desired position so the motors dont try to run either direction.  No on/off logic or anything needed. Works great.

[jfjoubert]

Thanks for the info.

I managed to drive my steppers via Arduino and ArdsimX and I'm using the virtual throttle handle angle and comparing it to the value of the actual throttle axis value. My Arduino has a potentiometer which is mapped as the throttle axis so just checking whether there's a difference and then running the stepper to catch up works like a charm.

Now I just need to figure out a homemade slip clutch... 

[737NUT]

You can find slip clutches on ebay, look for PolyClutch

[jfjoubert]

Thanks for the info...