Troubleshooting ArduCopter Motor Timeouts: DShot Signal Variance on Cube Orange+ V2

ArduCopter Copter 4.5
1

Hi @philip, Everyone,

I am relatively new to ArduCopter and am currently troubleshooting an issue where the motors suddenly stop during operation. My log analysis shows an input signal timeout (no signal received by the ESCs). To investigate, I probed the Pixhawk output pins using a DSO in a bench setup.

Setup:

  • FC: Pixhawk Cube Orange+ V2 (ARDUCOPTER V4.5.7)

  • Method: Bench testing via DSO probing

Test Cases:

Observations & Queries:

  1. Why is there a visible difference between the DShot signals on AUX OUT vs. MAIN OUT?

  2. Is this variance caused by the hardware routing differences between the FMU (Flight Management Unit) and the IOMCU (Input/Output Microcontroller)?

  3. If DShot is typically recommended for AUX ports, what could be causing the inconsistent behavior I’m seeing there?

  4. Is DShot on the MAIN OUT ports considered reliable and “flight-ready” for this hardware revision?

I would appreciate any insights from those familiar with the Cube Orange+ V2 timing architecture.

1 Like
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@Kashpandit19011990 the reason you are seeing that is because the MAIN OUT 1 is driven through a unidirectional high power protection circuit and AUX is through bi-directional but not as high power protection circuit. its simply an artifact of drivestrength differences between AUX and MAIN.

Only reason to use DShot from AUX is if you need bidirectional capability or are running DShot600 and up.

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Update to 4.7-beta. You are missing out on multiple
Improvements by remaining on stale firmware.

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Just so we can all be clearer, you can set LOG_DISARMED,1 and do the motor tests again then upload that .bin log to a filesharing service and provide the link to it here.
Remember to set LOG_DISARMED,0 afterwards.

This gives us all the parameters and the RC Outputs for motor tests. RC Out in logs is scaled between 1000pwm and 2000pwm even though DSHOT is a serial protocol with a throttle percentage. It’s just the best way to record it in logs.