Hi Keith and good morning,
I believe I misunderstood what you said in the previous post - apologies .
. I believe that you have created a gauge for your own use.. not one modelled on the real aircraft which slightly confused me - (not difficult at my age)...
Can I please ask how you are actually accounting for any difference in trim levels from AP to manual as far as the actual pitch is concerned ? (and response when flying)
I believe you are using a pitch indicator comparing the two (auto and manual trim). Are you actually integrating the two to the actual trim without any manual intervention between AP and manual ? - meaning are you getting a smooth transition.
I agree that whilst on AP the dataref needs to be read for the pitch to control the trim wheel drive, and also that the manual trim wheel drive needs to write the dataref. This is separate from the pitch trim
'indicator' though ?
I would presume that when you are driving the trim wheel in AP trim or electrical button trim mode then that will move the stepper - and presuming that is directly linked to the incremental encoder ?
So also i would presume that you have full data all the time as to the position of the trim wheel and actual trim in the sim ?. - ie, when starting the sim, the dataref is read as to the position of the trim (which gives you an incremental encoder reference starting point), OR you write the position on start-up from a pre-set level TO the dataref to set it to a know position on start-up which is the same on every sim start-up.
When the AP mode is engaged, then the dataref read is the controlling factor ? - and when in manual mode the dataref write is the controlling factor ?. This would be as I expect. to allow for any variation - (if needed) then the encoder count can be reset to a matched level on AP disconnect. This would always keep the two in sync hence needing no manual intervention.
How do you find the 28BYJ_48 steppers for driving the trim wheel as I have always found that they have low torque (although they are slightly better with 12 - 15V drive) - I was looking back though some of my arduino code and I think I was using 2074 as the e pulses needed allowing for 360 degrees allowing for the on board gearing in the unit.
I always found it was really easy to skip a step or two with the slightest load with the 28BYJ_48. I am actually surprised you got it to turn a trim wheel. Nice one.
Note to self - I need to stop thinking about 'gauge' as a copy of an actual real word aircraft unit and more as a possible AM produced unit
- I am too used to sketches and modules....
Would love to see an image of the quadrant assembly.
Joe