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Fried Pixhawk and main voltage reg board using pymavlink console command

(Tim) #1

Setup: BLueRov2 electronics on benchtop; T200 thruster connnected to ESC1; benchtop 16V/9A supply connected to main votlage regulator, running pymavlink on topside mac.

Action: Used Bluerobotics pymavlink python script examples (https://www.ardusub.com/developers/pymavlink.html) to arm and manual mode vehicle. Issued the set_ rc_channel_pwm(4, 1900) command for 10 sec, the thruster spun up normally and then all of sudden the lights on RPi/Pixhawk went out and the benchtop power supply indicated 0V/5A. I shut down the bench power supply immediately.

Problem: The BlueROV2’s main voltage regulator appears to be toast as does the Pixhawk’s BEC contained on the same board. The RPi still boots up with USB power supply and is fine but the Pixhawk won’t communicate and only issues a feeble blinking green power light.

We plan on replacing the main voltage regulator and the Pixhawk, if they are not salvagable, however I’d like the community’s thoughts as to what happened. It seems that the commanded pwm of 1900 should be well within the power rating for the electronics.

Thanks in advance, Tim

(Patrick José Pereira) #2

In the RC documentation you can see the channel 3 as throttle, and in T200 documentation the value of 1900 as maximum reference, sending a 1900 pwm value in channel 3 puts the ROV in full throttle mode, have you done this underwater ?

(Tim) #3

Benchtop with single thruster … and I typo’d. I issued the

set_ rc_channel_pwm(4, 1900)

command yaw full throttle for 10 sec. The test was intentional. I didn’t see anything in the documentation indicating the electronics were at risk. We have benchtop tested the T200s full throttle for 10 seconds with a different set of ESCs.

(Patrick José Pereira) #4

Underwater and running at full throttle you can get almost 80A, that’s why I’m asking.
But, if you are doing a test with only one thruster it should not be a problem, which ESC are you using ?

(Jacob) #5

Your power module was compromised somehow. This test should have been fine. We have seen the same trouble from some of these power modules and are looking for a replacement. Please contact support@bluerobotics.com for replacements.

(Tim) #6

Patrick thanks for responding. We are using the new BlueROV2 Basic ESCs I presume since we just purchased the electronics package last November.

(Tim) #7

Thanks Jacob, will do!