Power Brick: negative voltage output for current-sense

Hardware
1

I have two power bricks and have just tried to implement current monitoring using this PixHawk 2, and it appears that the power brick has been incorrectly assembled, since the current measurement does not work.

Debugging, we’ve found that the analog voltage output representing current is negative. Measuring low currents we saw:
320mA -> -17mV
150mA -> -8mV
Gives a coefficient of 53mV/A or 18.8A/V which seems correct, just negative.

The only explanation I can think of for this inverted value is that the male and female connectors have been assembled on the wrongsides of the board.

I would have thought if this were the case, then other people would have run into the issue, but can’t find anything about it.

Seems like a pain to swap the power connectors (and a bit risky with the heat required to desolder two high-current pins simultaneously off the PCB). Also seems like a pain trying to re-route the differential amplifier inputs.

Any ideas?

2

Has no-one seen this problem? I have two power bricks putting out negative current readings. Surely I’m not the only person to get this problem.

3

So I switched the genders on each end, expecting that the differential voltage across the sense resistor would then be reversed, correcting the output voltage for the current sense. But it still behaves the same! So current in either direction sensed as a negative output voltage. Has no-one seen this?