OpenMarine

OK folks... this one is driving me crazy.  It seemed like my MacArthur HAT (which I just received last week) was going well with my configs.  Howver, I was getting nothing on my 'candump can0' at all.  A bunch of troubleshooting ended me at this problem:

With the HAT completely disconnected from everything (N2k network, Pi 5 board, power and IMU modules including their mounting hardware... everything) I get the following resistance measurements between CAN-H and CAN-L with CAN TERM jumpered to:

Closed:    119.0 Ω
Open:      31.40 Ω
No jumper: 31.45 Ω

Has anyone else come across this or have any idea what's going on?

TIA!

If I am not wrong that are the expected values.

Check the resistance with the HAt connected to the CAN bus following this: https://macarthur-hat-documentation.read...00-network

Are you sure there is traffic in your CAN network?

NMEA 2000 networks require two terminators (120Ω resistors) at each end of the network to ensure stable communication. The MacArthur HAT includes an optional 120Ω termination resistor to address cases where a network terminator is missing or when connecting directly to another NMEA 2000 device. smash karts

It looks like the HAT itself has about 60 Ω across CANH–CANL internally (hence \~31 Ω in parallel with the 120 Ω terminator), so that behavior is expected—your readings don’t indicate a fault.

ym2c:

Open: 31.40 kΩ
No jumper: 31.45 kΩ. (kiloohms!)

this will be more realistic and correct mesurement.

Hello Larry

is your Problem solved?