I have just upgraded a Spirit Pro to 3.4.3 and have a Geolink v1 on 1.2.1

On my unit, contrary to the Geolink manual, my Altitude Limit thresholds are:
On(1) - +100 to about +50%
Off - About +45 to +5%
On(2) - About 3% to -100%

This caused the Altitude function to be in mode On(2) with minimum altitude 2.7m at spoolup. Some anxious moments when it tried to take off at spoolup!

Wouldn't it be safer to have On(2) only between -5 and -100%, so that older units don't have unexpected behaviour. What I don't understand is that Geolink firmware has not changed, but the behaviour changed after upgrading from (I think) 3.3.3. (I have been away from heli flying for a while.)

Hello,

the behavior should be identical to previous version if your channel range was OK for OFF. This is approximately 0%, while there is quite high range around this value in both direction to not accidently trigger the function.
If it is not OFF at 0% then there is something wrong, likely there is a channel subtrim in the radio. It can be verified in the Channel Monitor of the radio.

It is very important to always read ChangeLog for each version and versions between. All the changes are described there. Because there could be a major change which can cause unexpected behavior and a potential crash.

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Spirit System developer

I have an Frsky X10 on OpenTX. For debugging this problem I assigned a slider to the Altitude Limit channel, and read the threshold values from the Outputs screen. I am confident that the values I quoted are correct.

It was working before, no changes to the radio. In fact in the Off position I output a fixed value of 0% to the channel. I now have to output something like 20% for Off, 100% for On(1). I don’t use On(2).

Please take a look at the Channels window in the Spirit Settings to see what unit can see.
Something is causing that channel is off. However there was no change in the firmware for S-BUS for years if you are using this protocol.

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Spirit System developer

I just did the following check: I have Altitude Limit as an Input which is assigned to mixer and output on CH12, with a slider assigned for testing. I assigned the same Input to the Pitch CH6, which I can check using the Spirit Diagnostics screen. I get identical values, i.e.
Pitch = 0% with slider at centre, at this point Altitude Limit says On(2).
Pitch = 50% when Altitude Limit says Off.
Pitch = 100% when Altitude Limit says On(1).

Then connected an ISDT BG 8S battery checker which has an SBUS receiver check function to the SBUS out on the receiver:
Slider at +100: SBUS = -115
Slider at 0: SBUS = 4
Slider at -100: SBUS = 124

I dont understand the pitch channel settings from the description, but it look like 50% is 0%. So that a negative part of the channel is missing.
Normally when you set channel to 0% (center in other words) it should be OFF. In the Spirit Settings - Channels window it should show the bar in the center as well.

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Spirit System developer

I think the problem is this:
Centre (0) on frsky is 1500 us.
Centre on Futaba is 1520us.
SBUS is a Futaba standard.
20us is 4%.
This explains the reading of 4 I got using the BG 8S receiver SBUS checker.

This also explains what is happening. My FrSky X10S puts out 0% i.e. 1500uS for Altitude Limit = Off but the Geolink is seeing this as SBUS = 4 so it switches to On(2). (Positive SBUS values result from negative X10S values.) The Geolink want to see SBUS = 0 i.e. 1520uS for the Off condition.

If I change my X10S to put out >5% then Geolink switches to Off. So this is my work-around, but I don't understand why it worked before.

I think having no deadband between the On(2) -1% to -100% and the Off at 0% is a problem.

Hello,
I have also a Frsky X10S Express - all my max. and min. values are at 83 % !!
(I don't speak here about my throttle channel ! )

If I have in my outputs 83 then I get in the Spirit Settings +100 !
Same for -83 then I get in Spirit Settings -100 !

For example three values are wanted (with a 3 position switch):
Sw Pos down: -83 (min) -100
SwPos middle: 0 (middle) 0
Sw Pos up: +83 (max) +100

There is no stetting in the transmitter that has only "0" for the min. values !
I think the settings in the transmitter are wrong set resp. not right setted -

Regards