Vario Height Control

On the last flight I had the throttle set at just over the neutral position, which led to the 'copter making an ascent to 50m instead of performing its waypoints at 15m. I wanted to double-check that I fully understand the altitude controls so I thought I'd write down a bit of research.

There are three kinds of altitude control settings for the MK: manual, Height Limitation Control , and Vario Altitude Control.  From the 0.84 Firmware documentation, I find that the altitude control for waypoints "works only in vario-mode of the hight control. The gas-stick must be in the hoovering hovering position in that case." So comparing our two main modes:

With Vario OFF (manual mode ON):

• throttle neutral -> propeller speed is at some level -> 'copter may ascend or descend depending on relative power of propellers against the air
• throttle up -> propeller speed increases -> 'copter ascends
• throttle down -> propeller speed decreases -> 'copter descends

with Vario ON (manual mode OFF)

• throttle neutral -> 'copter remains at the height it is at
• throttle up -> 'copter told to go higher -> it increases its own propeller speeds and ascends
• throttle down -> 'copter told to go lower -> it decreases its own propeller speeds and descends

When switching between Vario mode ON and OFF, it's best to have the throttle at neutral. Otherwise it can gain or lose altitude unexpectedly. I found a video with a little demo on a quadkopter.

According to the 0.86 Firmware documentation, I can get more info from the HOTT transmitter screen:

Vario - symbol
This shows the setpoint of the altitude control. (vario mode only)
= : no change in altitude
+ : increase altitude
- : decrease altitude
^ : increase (command from NC: (Waypoint))
v : decrease (command from NC: (Waypoint))
The background of the symbol is black, if the altitude control is activated.

I've tried to find the relevant screens on the transmitter with the 'copter switched on and calibrated, but not flying, and so far I can't find anything like the screens described. So on another still day, I should take it up a bit, put it in PH/AH and see if I can find the telemetry data described.