Recently, I have been having an issue with my Here GPS paired with my Cube Orange over CAN. I have been flying successfully with no issues for over a few years, but recently (and consistently) the GPS fails mid-flight. Consistent between the Here3+ and Here4 I swapped it with, the quad boots and flies just fine for a few minutes, before I completely lose my GPS fix and mag data and the drone enters emergency land mode. On landing, the LEDs on the Here GPS are off. My VCC is about 4.8-4.9V, which should be fine? I have attached my log file and a screenshot.
I can look into power issues, but is there anything else that could be likely? Is my Cube’s CAN rail failing? Or maybe some issue with the GPS (the Here4 was taken off another quad)? Also, the GPS populates as two devices under MP dronecan with the same node ID (124), leading to also 2 mags (which are really one). Could that be related?
all accessories run from the same +5v (1A or 1.5A ?) regulated supply (I2C, CAN, Serial2,3,4,5)
except Serial1 (Telem1) has it’s own +5v 1.5A supply
So potentially you can move some of the devices to their own external BEC, or maybe you can shift a serial device to Telem1
In logs check POWR.Flags
1 MAV_POWER_STATUS_BRICK_VALID // main brick power supply valid
2 MAV_POWER_STATUS_SERVO_VALID // main servo power supply valid for FMU
4 MAV_POWER_STATUS_USB_CONNECTED // USB power is connected
8 MAV_POWER_STATUS_PERIPH_OVERCURRENT // peripheral supply is in over-current state
16 MAV_POWER_STATUS_PERIPH_HIPOWER_OVERCURRENT // hi-power peripheral supply is in over-current state
32 MAV_POWER_STATUS_CHANGED // Power status has changed since boot
The values represent a bitmask, so add up the decimal values listed here.
Thank you so much! I wasn’t aware that the Cube doesn’t share the 5V-in directly (I’m using a 5.5A supply). Interestingly, besides the Here GPS on the CAN line, I don’t think I have any other devices powered off the cube, except for some small ones (e.g., buzzer, safety switch). I have an RFD900 on Serial1 (powered using aux 5V) and a TF02 lidar (also 5V pulled out and connected to an aux 5V).
Is it possible that maybe there is a short somewhere causing it to overcurrent? Or maybe the regulator is overheating and browning out (the heat log shows a consistent rise)? Once I’m back in the lab on Monday I’ll try moving some stuff around / unit testing.
I’ve found the RFD900 is OK to be powered from the Serial1/Telem1 provided you drop the output to 27db or 28db and I’ve not had any issues. This will reduce the range, but only from about 150km back to “believable”.
You could run a Here4 off an external supply and the Here3 off the inbuilt supply for some extra redundancy, something like that.
That temperature rise in the Cube is OK, nothing wrong there.
Gotcha thanks! Also, I’m running just the single Here4 (I had swapped it in for the Here3 I had earlier because I thought the issue was with the GPS, not overcurrent).
It wss suggested that the RFD900 needs to run on a separate power source. There is too much power being drawn thru the FC to be heathy. It will overheat the FC and board.
Just an update, did some benchtop testing with props off, and was unable to replicate the issue. As far as things actually drawing power from the Cube.
RFD900x - Telem1
Can1 - Here4 GPS
External Baro (BMP280) - I2C1
Buzzer - USB
Safety Switch - GPS1
I’ll try moving the RFD off the Pixhawk or reducing its TX power, but if it’s on a separate power line anyway within the Cube, it shouldn’t be an issue. I’ll do some actual flight testing soon and see if it occurs again in the air.
The error in the log was for the (ordinary) peripheral 1amp supply (CAN, I2C, Telem2…)
The error was not for the high power 1.5amp supply (Telem1 only), so really whatever was connected to Telem1 did not cause the issue.
It wouldnt hurt to check all the ground connections, especially where an external BEC is involved. The bible:
Unrelated, but I’d lose the safety switch, because it’s the opposite of safety to reach into the region of spinning props to operate the switch. I’ve never had an issue with a copter magically arming by itself. I set these:
Hey Shawn, thanks for the input (checked grounds and removed the safety switch ). I plan to do some flight testing tomorrow, and I’ll leave an update based on how it goes.
). I plan to do some flight testing tomorrow, and I’ll leave an update based on how it goes.