Wren 44 ECU Calibration problem

[kevinww]

Having a problem Calibrating ECU to new radio, so hopefully someone will have a solution.
This is one of he first batch of 44 heli turbines.

Background, changing radio to DX18 and AR9020 RX from DSX9 (JR9303X for those in the US) and VBar using satellites.

ECU Calibrated fine on the previous setup, now with the new setup, can't get past the data terminal showing sticklo at startup.

So far I've tried the following :-

1. Disabled all sliders wheels on radio etc.
2. Rebound radio to RX in DSMX 11ms, 22ms and DSM2.
3. Reversed throttle channel, opposite of previous TX returned to original setting after test.
4. Checked throttle output is OK from RX with a servo, which was fine.
5. Changed lead from RX to ECU, to rule out the lead.
6. Rebound original DSX9 with no changes to settings to new RX.
7. Powered heli before the TX, terminal shows ready, switch on the TX and
terminal then shows failsafe, so it seems like the ECU is getting either no signal or
an ambiguous signal from the RX.

At this point I'm stumped and the only other option is to reset everything back to old radio and VBar with satellites and see if problem persists. Unless anyone has any other suggestions.

[kevinww]

I've got a bit further.

Ignored the sticklo at startup and did the calibration anyway as per manual.

Seems to have calibrated OK but at next rx startup terminal shows Ready not Trim Low.

I only get the trim low shown in the terminal when I activate the throttle cut switch that was used as the trim down position during calibration, from memory I dont remember it behaving thi way before and its at odds with the manual.

[cbdane]

Are you sure that your radio is configured in standard framerate, i.e. 50 frames/second, instead of the high framerate mode?

[kevinww]

That was one of my original thoughts so switched it to 22ms with same results. I believe it has calibrated now, as elsewhere in the manual it shows that terminal will show ready until trim down is active when trim low will be shown. Just really after confirmation that this is correct now.

[Skiddz]

Potentially stupid question here, but what does your throttle curve look like? We see a lot of new guys (Not saying you're new) who get done setting up their heads and go to calibrate their ESCs and can't figure out why moving the stick physically to the middle sows high stick in the radio etc.. - it's usually a non-linear throttle curve.

Might be worth a quick check.

[kevinww]

Linear throttle curve 0 - 100.

[kevinww]

All looks good now, just completed a test start and run and it behaves perfectly.