mRo Control Zero Classic No 5V on main servo outputs

Hardware Vendors mRobotics
1

Hi, I purchased a mRoControlZeroClassic as a drop in replacement for the pixhawk1 on the BlueRobotics BlueROV2 after some water damage… needless to say it has not been very “drop-in”…

I can’t get any 5V output on the main servo outputs. On the previous pixhawk the camera tilt servo was on an aux channel whose power rail was provided by the SBUS input. I tried doing the same thing with the Control Zero Classic, but no luck. Even with SBUS connected there is no 5V on channels 1-12. The left 4 outputs have 5V available though (even the SBUS outputs 5V), which is odd, and obviously an easy hack is to separately wire this 5V to where it’s available and use the standard servo channel. But this should work.

Anyone have any ideas?

2

https://ardupilot.org/copter/docs/common-powering-the-pixhawk.html

3

I am not using the pixhawk.

4

No surprise there it’s completely different architecture in the same old case. It doesn’t have an IOMCU for one thing which is a major difference. Anyway, from the manual:

Zero
Zero576×191 78.3 KB

5

Well if you know anyone in the marketing department at 3DR tell them to not say that on the website Control Zero Classic | Modern Pixhawk 1 Replacement with Advanced Features.

What is IOMCU? How do you know it doesn’t have one? It is frustrating how little documentation there is about this board.

I am still unclear on what powered externally means. Do I have to directly apply power to this rail here?

6

Yes, you have to apply 5V power to the rail directly via a voltage regulator / BEC.

7

Where on that page does it say 5V powered servo rail?

Yes, you have to supply power to the rail as indicated by the graphic.

8

I know because the specs say “IO Processor-No”
Specs

AFAIK all Mro Flight Controllers have isolated output buss’s going back to the original PixRacer.

But you are right that this statement is wrong, “drop in, substitution for the Pixhawk 1”

9

Correct me if I’m wrong, but that’s part of the Pixhawk FMU spec, no?

So the boards that DO supply BEC power to the rail are non-compliant, IIRC (particularly if it’s not configurable/severable via jumper/solder pads).

10

If I get your meaning yes. One difference, among many, between Pixhawk 1 and This Mro version is the former can be powered from the servo rail while Mro is completely isolated. But it does not supply power on the rail unless you connect a BEC.